Maternal SARS-CoV-2 Vaccination and Infant Protection Against SARS-CoV-2 During the First 6 Months of Life

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Thomas Ray, Bruce Fireman, Evan Layefsky, Kristin Goddard, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2143552/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 28 Feb, 2023 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract We examined the effectiveness of maternal vaccination against SARS-CoV-2 infection in 30,288 infants born at Kaiser Permanente Northern California from December 15, 2020, to May 31, 2022. Using Cox regression, the effectiveness of maternal vaccination was 85% (95% confidence interval [CI]: 67, 93), 64% (CI: 43, 78) and 57% (CI: 36,71) during the first 2, 4 and 6 months of life, respectively, in the Delta variant period. In the Omicron variant period, the effectiveness of maternal vaccination in these three age intervals was 22% (CI: -18,48), 14% (CI: -10,32) and 12% (CI: -4,26), respectively. Over the entire study period, the incidence of hospitalization for COVID-19 was lower during the first 6 months of life among infants of vaccinated mothers compared with infants of unvaccinated mothers (21/100,000 person-years vs. 100/100,000 person-years). Maternal vaccination was protective, but protection was lower during Omicron than during Delta. Protection during both periods decreased as infants aged. Figures Figure 1 Introduction In the US, as of the end of September 2022, almost 15 million children have tested positive for severe acute respiratory syndrome corona virus 2 (SARS-CoV-2), the virus that causes Coronavirus Disease 2019 (COVID-19). Children currently account for about 18.5% of reported COVID-19 cases in the US 1 . SARS-CoV-2 infection can lead to severe illnesses and hospitalizations in children and infants 2-5 . During Omicron predominance, children aged <6 months accounted for 44% of hospitalizations among children ages 0 – 4 years 3 . Vaccination offers the best way to protect against COVID-19 and its complications. COVID-19 vaccines have demonstrated both high efficacy in clinical trials and high real-world effectiveness, especially against the original and Delta variant of the virus 6-10 . Real-world data suggest lower COVID-19 vaccine effectiveness against Omicron variants 11-14 . However, infants aged < 6 months are not currently eligible for any currently available COVID-19 vaccines and must rely on placentally acquired immunity from their mothers. Like influenza and Tdap vaccines 15,16 , data suggest that vaccination during pregnancy may protect infants who are not old enough to be vaccinated against COVID-19. Two recent epidemiological studies found that vaccination during pregnancy was associated with a reduced risk of SARS-CoV-2 infection in infants during their first 4 months of life and a reduced risk of hospitalization during the first 5 months of life 17,18 . The objective of this study was to further evaluate the effectiveness of at least 2 doses of mRNA COVID-19 vaccination during pregnancy for preventing SARS-CoV-2 infection in infants during the first 2, 4 and 6 months of life during the Delta and Omicron variant periods. We used two different study designs: a primary design using a cohort analysis in which infants of vaccinated pregnant persons were compared with infants of unvaccinated pregnant persons. In this design, we used Cox proportional hazards models with calendar days as the underlying scale to estimate hazard ratios and calculated vaccine effectiveness as 1 minus the hazard ratio. Secondarily, we used a Test Negative Design (TND), which is a case control study, to compare the odds of vaccination among mothers of infants who tested positive vs. the odds of vaccination among mothers of infants who tested negative. In this analysis, vaccine effectiveness was evaluated as 1 minus the odds ratio. The aim of the secondary design was to compare the results from the cohort and TND design. Results Descriptive statistics and characteristics Between December 15, 2020, and May 31,2022, we identified 62117 infants born at Kaiser Permanente Northern California (KPNC), an integrated health care delivery organization. Among these infants, we excluded 21918 (35.3%) based on maternal exclusion criteria and 10408 (16.0%) after applying infant exclusion criteria (Figure 1). The final study population included 30288 (48.8%) infants who were KPNC members at least 2 months after birth. The mean age at pregnancy onset was 31 years (standard deviation 4.66 years). Most mothers (66.15%) were between ages 25 and <35 years, and more than a quarter (27.26%) were of Asian race, 5.16% were Black, 24.45% were of Hispanic ethnicity and 37.57% were White. Among the infants in the cohort, 19179 (63.32%) of the mothers were unvaccinated during pregnancy, 1035 (3.42%) of the mothers received 1 dose of a mRNA COVID-19 vaccine, 9456 (31.22%) received 2 doses, and 618 (2.04%) received 3 doses during pregnancy (Table 1). During the first 6 months of life, 940 (3.10%) infants tested positive for SARS-CoV-2 by polymerase chain reaction (PCR) test and 10 (0.03%) infants were hospitalized with a positive SARS-CoV-2 test. Vaccine effectiveness: Primary design cohort analyses During the Delta dominant period, the crude incidences of testing positive for SARS-CoV-2 during the first 2, 4 and 6 months of life were lower among infants whose mothers received at least 2 doses of mRNA COVID-19 vaccines during pregnancy (0.74, 1.38, and 1.55 infants per 100 person years [PY], respectively) than those whose mothers were not vaccinated during pregnancy (5.53, 5.18, and 4.83 infants per 100 PYs, respectively). After adjusting for covariates, vaccination during pregnancy significantly reduced risk of the infant testing SARS-CoV-2 positive by 85% (95% confidence interval [CI]: 67, 93) during the first 2 months of life, 64% (95% CI: 43, 78) during the first 4 months of life and 57% (95% CI: 36,71) during the first 6 months of life (Table 2). During the Omicron dominant period, vaccination during pregnancy reduced the risk of the infant testing SARS-CoV-2 positive by 22% (95% CI: -18, 48) during the first 2 months of life, 14% (95% CI: -10, 32) during the first 4 months of life, and 12% (95% CI: - 4, 26) during the first 6 months of life (Table 2). In supplemental analyses by trimester of vaccination, receipt of the second dose during the second and third trimester reduced the risk of infants testing SARS-CoV-2 positive during the Delta dominant period by 91% (95% CI: 63, 98) and 87% (95% CI: 55, 96), respectively, during the first 2 months of life, by 60% (95% CI: 23, 79) and 70% (95% CI: 43, 84) during the first 4 months of life and by 65% (95% CI:33, 81) and 54% (95% CI: 27, 71) during the first 6 months of life (Table 3). We observed a similar pattern in vaccine effectiveness by trimester during the Omicron dominant period, however, estimates of vaccine effectiveness by trimester during the Omicron period were imprecise and much lower than during the Delta period (Table 3). Over the entire study period, the crude rate of hospitalization with a SARS-CoV-2 positive test was lower during the first 6 months of life among infants whose mothers received at least 2 doses of mRNA COVID-19 vaccines during pregnancy compared with infants whose mothers were unvaccinated during pregnancy (21/100000 PY vs. 100/100000 PY). VE against hospitalization was not estimated because of the very small number of hospitalized cases. There were only 1 hospitalized case among the children of vaccinated mothers and 9 hospitalized cases among the children of unvaccinated mothers (Table 1). Secondary analysis results using a test negative design (TND) In the TND, we estimated that during the Delta predominant period, maternal vaccination reduced the infant’s risk of testing SARS-CoV-2 positive by 98% (95% CI:75, 100) during the first 2 months of life, 72% (95% CI: 55, 83) during the first 4 months of life, and 63% (95% CI: 45, 75) during the first 6 months of life (Supplemental Table). During the Omicron dominant period, maternal vaccination reduced the infant’s risk of testing SARS-CoV-2 positive by 55% (95% CI: 15, 76) during the first 2 months of life, 37% (95% CI:12, 55) during the first 4 months of life, and 40% (95% CI: 25, 53) during the first 6 months of life (Supplemental Table). Discussion In this large study which included >30,000 infants, we found that receipt of at least 2 doses of mRNA COVID-19 vaccine during pregnancy was associated with a decreased risk of infants testing SARS-CoV-2 positive during their first 6 months of life. Maternal vaccination reduced the infant’s risk of testing SARS-CoV-2 positive initially by 85% which decreased to 57% by 6 months of life in the Delta dominant period. However, vaccination during pregnancy was less effective at protecting infants against SARS-CoV-2 infection during the Omicron period. As infants aged, protection provided by maternal vaccination decreased during both periods. Although the study was unable to directly estimate VE against hospitalization due to the small number of hospitalized cases, it found that over the entire study period, the incidence rate of hospitalization during the first 6 months of life was much lower among the infants whose mothers were vaccinated during pregnancy compared with those whose mothers were not vaccinated. These results suggest that in addition to providing protection against testing positive, vaccination during pregnancy may also provide protection against hospitalization (severe disease) in the infants during their first 6 months of life as previously reported recently 18 . Our findings that vaccination during pregnancy was effective at protecting infants during the Delta period are similar to those reported in a recent Norwegian study showing that mRNA COVID-19 vaccination during pregnancy was associated with a 71% decreased risk of testing positive for SARS-CoV-2 in infants during their first 4 months of life during the Delta period 17 . During the Delta period, we found that protection extended through the infant’s first 6 months of life. However, in contrast with the Norwegian study which reported that infants of mothers who were vaccinated had a 33% decreased risk of testing positive during the first 4 months of life during the Omicron period 17 , our study found a 14% reduced risk that was not statistically significant. Difference between the two studies might be due to population characteristics and to the timing of follow up as ours went through May 31, 2022, while the Norwegian study’s ended in April 2022. The finding that maternal vaccination was less effective at protecting infants during the Omicron dominant period is also consistent with previous studies which have reported decreased effectiveness of mRNA COVID-19 vaccines during Omicron among children and adults 14,19 . Recently another study reported that the effectiveness of mRNA COVID-19 vaccines against infections and hospitalizations among pregnant people was higher during the Delta period than during the Omicron period 20 . We observed that infant’s protection through vaccination during pregnancy decreased as they aged from 2 months to 6 months. These findings are consistent with diminishing of pregnancy derived antibodies in the infants over time 21 . A recent study found that the mean titer of maternally derived antibodies in infants of vaccinated mothers were higher at ages 2 months compared with antibody titers at ages 6 months 22 . Despite several studies showing that vaccination during pregnancy is safe for pregnant people 11-15 , vaccine uptake has been suboptimal in this group 23 . In the present study, the mothers of only 33% of infants in the cohort received at least 2 doses. More efforts are needed to promote COVID-19 vaccines for pregnant persons because vaccination provides protection to mothers and their infants until they are old enough to receive their own COVID-19 vaccines. Our study was strengthened both by its large sample size and our ability to follow infants through 6 months of age. In addition, our study period included two different SARV-CoV-2 variants, which allowed estimation of the effectiveness of vaccination during pregnancy in infants during both the Delta and Omicron variant periods. Our primary cohort analysis used calendar days as the underlying scale to ensure that we compared infants of vaccinated and unvaccinated mothers on the same calendar days because vaccination status during pregnancy and risk of SARS-CoV-2 infection varied over the study period. In this primary design, all eligible infants meeting inclusion criteria were included without sampling which improved power and minimized bias related to selection. Furthermore, it was reassuring that both the cohort and the secondary TND yielded vaccine effectiveness estimates in the same direction. Although both approaches adjusted for the same confounding factors, the effectiveness estimates from the TND were higher than those from the cohort design, which is consistent with our previous analyses of influenza vaccine effectiveness in which we also observed that the TND tended to result in higher vaccine effectiveness estimates than did our cohort analyses 24 . The TND, a case control study, has been commonly used in studies of the effectiveness of influenza vaccines and more recently COVID-19 vaccines. It is designed to better adjust for healthcare seeking behavior 25-27 , although it may also introduce other biases including selection bias 28 .The TND used analysis limited to the sample of infants who were tested for SARS-CoV-2. The study had limitations worth noting. Vaccinations were limited only to those received during pregnancy. We did not assess whether vaccines received before pregnancy or immediately after pregnancy were associated with reduced risk of testing positive for SARS-CoV-2 in infants. The study did not adjust for maternal SARS-CoV-2 infections during pregnancy. During the study period, home testing became more prevalent. It is possible that this practice may have led to some misclassification of outcome, and we were unable to assess whether this misclassification was differential between vaccinated and unvaccinated mothers. We did not have genotyping data to confirm the variant that infected infants who tested positive and instead relied on state data regarding circulating strain predominance in the Northern California region. Like all observational studies, our study results are susceptible to residual confounding. In conclusion, in this population-based cohort study, we found that infants born to mothers who received at least 2 doses of a mRNA COVID-19 vaccine during pregnancy were at lower risk of testing positive for SARS-CoV-2 and were at lower risk of hospitalization during the first 6 months of life compared with infants whose mothers were unvaccinated during pregnancy. Maternal vaccination was protective, but protection was lower during the Omicron period than during Delta. Protection during both periods decreased as infants aged from 2 months to 6 months. Overall, the study results support recommendations for vaccination during pregnancy to protect both mothers and their infants. Online Method Setting and Study Population The study setting was Kaiser Permanente Northern California (KPNC), an integrated healthcare delivery organization that provides comprehensive health care to approximately 4.4 million members as of 2019. Members receive almost all their medical care at KPNC-owned facilities, including clinics, hospitals, pharmacies, and laboratories. KPNC has a comprehensive electronic health record system that captures detailed information on all medical services, including immunization, membership enrollment including place of residence, demographics, and pregnancy related care from pregnancy onset to delivery and beyond. KPNC members are similar to the broad catchment population in Northern California in terms of sociodemographic characteristics 29 . Annually, approximately 40,000 births occur at KPNC facilities. The study was conducted among a cohort of infants born between December 15, 2020, and May 31, 2022. From this cohort, the study excluded the following infants born to: 1) mothers who were not between ages 16 and 50 years at pregnancy onset; 2) mothers who did not have a primary KPNC facility assignment; 3) mothers who were not continuous KPNC members from December 15, 2020 until delivery 4) mothers who had a positive nasal/throat swab for SARS-CoV-2 by polymerase chain reaction (PCR) prior to pregnancy onset; 5) mothers who had a positive SARS-CoV-2 antibody test documented by KPNC prior to onset of pregnancy; 6) mothers who received one or more doses of COVID-19 vaccine prior to pregnancy onset. We excluded these infants because we were primarily interested in estimating the effectiveness of at least 2 doses of mRNA vaccines received during pregnancy; 7) mothers who received other COVID-19 vaccine than mRNA vaccine during pregnancy; 8) mothers who did not receive their mRNA vaccinations in accordance with CDC recommendations – e.g., the timing between dose 1 and dose 2 was not within the recommended intervals; and 9) infants who did not become KPNC members within two calendar months of their birth. No other exclusion criteria were applied. The KPNC Institutional review board approved and waived consent for this study. Outcomes The outcomes were infant’s first positive nasal/throat swab for SARS-CoV-2 by PCR, and first COVID-19 related hospitalization, occurring during the first 6 months of life and recorded in the electronic health record. Exposure The exposure of interest was mRNA COVID-19 vaccination status during pregnancy in the electronic health record. Mothers were classified as either having had ≥ 2 doses of mRNA COVID-19 vaccines during pregnancy (and completed more than 7 days prior to delivery) or not having had any COVID-19 vaccines prior to delivery. We further classified vaccination status by the trimester within which the 2 nd dose was received. Covariates For mothers of infants in the cohort we extracted from the electronic health record data: age at pregnancy onset, race/ethnicity (Asian, Black, Hispanic, Pacific Islander, Multiracial, Native American, Other, White), the primary KPNC facility at which the woman received most of their health care, insurance payor (dichotomized as “Medicare/Medicaid/other subsidized insurance” and “Other”), neighborhood deprivation index [NDI] 30 categorized into quartiles with higher values representing greater deprivation), pre-pregnancy body mass index (BMI=kg/m2; underweight <18.5, normal 18.5-24.9, overweight 25.0-29.9, obese ≥30.0), pre-pregnancy diabetes status, pre-pregnancy hypertension and parity (0, 1, 2, 3, ≥4). For infants, we included age, as a categorical time-changing variable in 30-day increments and preterm status defined as gestational age at birth less than 37 weeks. Statistical analysis We conducted a descriptive analysis of the study population and calculated crude rates of SARS-CoV-2 infection and hospitalization by maternal vaccination status. In our primary analysis, we implemented a cohort study design where we used Cox proportional hazards models that allow for time-varying covariates to estimate the SARS-CoV-2 infection hazard ratio (HR) in infants of mothers vaccinated with at least 2 doses of mRNA COVID-19 vaccines during pregnancy versus mothers who were unvaccinated during pregnancy. We calculated vaccine effectiveness (VE) as 100% multiplied by 1 – HR. In all models, we used calendar days as the time scale to account for changes over time in SARS-CoV-2 circulation and vaccine uptake. Infants were followed from birth until first positive SARS-CoV-2 test by PCR at age 2, 4 or 6 months, with censoring due to death, health plan disenrollment, or end of follow-up (May 31, 2022). Models were adjusted for covariates listed above. To account for the correlation between infants with the same mother, we fit marginal Cox proportional hazards models using robust sandwich variance estimates. We ran separate models on the time periods associated with the Delta (7/01/2021 to 12/20/2021) and Omicron variants (12/21/2021 to 5/31/2022). We also conducted analyses based on the trimester during which the vaccine was received during pregnancy (first, second or third trimester). We conducted secondary sensitivity analyses restricting the population to infants who received at least one SARS-CoV-2 PCR test. In this analysis, we estimated the odds ratio (OR) of vaccination of mothers of infants who tested positive for SARS-CoV-2 versus infants who tested negative using logistic regression models conditioned (stratified) on the calendar date of the test so that infants testing positive on a certain day were compared to infants testing negative on that same day. We calculated VE as 100% multiplied by 1- OR. This case-positive, control-test-negative design also referred to as the test negative design (TND) has often been used in studies of vaccine effectiveness. The TND is designed to better control for bias related to health care seeking behavior 25-27 . Models in this analysis were adjusted for the same covariates included in the primary analysis. All analyses were conducted using SAS software, v9.4. and statistical significance was assessed at two-sided p≤0.05. Declarations Funding Source: The study was funded by the National Institute of Allergy and Infectious Disease grant # 1R01AI168373-01 References American, Academy, of, et al. Children and COVID-19:State Data Report. A joint report from the American Academy of Pediatrics and the Children’s Hospital Association. 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The case test-negative design for studies of the effectiveness of influenza vaccine. Vaccine . Jun 26 2013;31(30):3104-9. doi:10.1016/j.vaccine.2013.04.026 Jackson ML, Nelson JC. The test-negative design for estimating influenza vaccine effectiveness. Vaccine . Apr 19 2013;31(17):2165-8. doi:10.1016/j.vaccine.2013.02.053 Coulton BL, Thomson K, Symmons DP, Popert AJ. Outcome in patients hospitalised for psoriatic arthritis. Clin Rheumatol . Jun 1989;8(2):261-5. doi:10.1007/BF02030083 Ainslie KEC, Shi M, Haber M, Orenstein WA. On the bias of estimates of influenza vaccine effectiveness from test-negative studies. Vaccine . Dec 19 2017;35(52):7297-7301. doi:10.1016/j.vaccine.2017.10.107 Gordon N, Lin T. The Kaiser Permanente Northern California Adult Member Health Survey. Perm J . Fall 2016;20(4):15-225. doi:10.7812/TPP/15-225 Messer LC, Laraia BA, Kaufman JS, et al. The development of a standardized neighborhood deprivation index. J Urban Health . Nov 2006;83(6):1041-62. doi:10.1007/s11524-006-9094-x Tables Table 1. Characteristics of the Study Population: Infants Born at Kaiser Permanente Northern California December 15, 2020 – May 31, 2022. Characteristics Infants included in the study N=30,288 n(%) Infants whose mothers were vaccinated during pregnancy N=11,109 n(%) Infants whose mothers were not vaccinated during pregnancy N=19,179 n(%) Maternal age at pregnancy onset (years), mean (std) 31.62 (4.66) 32.59 (4.31) 31.06 (4.76) Maternal age category (years) 16 - < 25 2,092 (6.91) 393 (3.54) 1,699 (8.86) 25 - <35 20,036 (66.15) 7,047(63.44) 12,989 (67.73) 35 - <50 8,160(26.94) 3,669(33.03) 4,491(23.42) Maternal race/ethnicity Asian 8,255 (27.26) 3,741 (33.68) 4,514 (23.54) Black 1,564 (5.16) 373 (3.36) 1,191 (6.21) Hispanic 7,405 (24.45) 2,198 (19.79) 5,207 (27.15) Pacific Islander 246 (0.81) 74 (0.67) 172 (0.90) Multiracial 108 (0.36) 37 (0.33) 71 (0.37) Native American 764 (2.52) 289 (2.60) 475 (2.48) Other/unknown/multi-racial 566 (1.87) 227 (2.04) 339 (1.77) White 11,380 (37.57) 4,170 (37.54) 7,210 (37.59) Parity, n (%) 0 12,084 (39.90) 4,809 (43.29) 7,275 (37.93) 1 11,180 (36.91) 4,259 (38.34) 6,921 (36.09) 2 3,921 (12.95) 1,171 (10.54) 2,750 (14.34) 3 1,212 (4.00) 279 (2.51) 933 (4.86) 4+ 576 (1.90) 130 (1.17) 446 (2.33) Unknown 1,315 (4.34) 461 (4.15) 854 (4.45) Medical comorbidity before pregnancy, n (%) Diabetes 490 (1.62) 221 (1.99) 269 (1.40) Hypertension 2,469 (8.15) 916 (8.25) 1,553 (8.10) Body Mass Index Underweight 658 (2.17) 272 (2.45) 386 (2.01) Normal 12,478 (41.20) 4,870 (43.84) 7,608 (39.67) Overweight 8,840 (29.19) 3,127 (28.15) 5,713 (29.79) Obese 8,206 (27.09) 2,805 (25.25) 5,401 (28.16) Unknown 106 (0.35) 35 (0.32) 71 (0.37) Type of insurance Subsidized (Medicare/Medicaid/other subsidized insurance) 2,007 (6.63) 460 (4.14) 1,547 (8.07) Non-subsidized 28,281(93.37) 10,649 (95.86) 17,632 (91.93) Neighborhood Deprivation Index (quartile), n (%) First quartile 1 (least deprived) 7,481 (24.70) 3,651 (32.87) 3,830 (19.97) Second quartile 8,101 (26.75) 3,010 (27.10) 5,091 (26.54) Third quartile 7,257 (23.96) 2,379 (21.42) 4,878 (25.43) Fourth quartile (most deprived) 7,396 (24.42) 2,046 (18.42) 5,350 (27.90) Missing 53 (0.17) 23 (0.21) 30 (0.16) Preterm birth 2,256 (7.45) 775 (6.98) 1,481 (7.72) mRNA COVID-19 vaccine doses 0 dose 19,179 (63.32) 0 (0.00) 19,179 (100) 1 dose 1,035 (3.42) 1,035 (9.32) 0 (0.00) 2 doses 9,456 (31.22) 9,456 (85.12) 0 (0.00) 3 doses 618 (2.04) 618 (5.56) 0 (0.00) Gestational age at COVID-19 vaccination for second dose First trimester 2,081 (6.87) 2,081(18.73) 0 (0.00) Second trimester 3,669 (12.11) 3,669 (33.03) 0 (0.00) Third trimester 4,324 (14.28) 4,324 (38.92) 0 (0.00) Gestational age at COVID-19 vaccination for those who only had one dose First trimester 56 (0.18) 56 (0.50) 0 (0.00) Second trimester 46 (0.15) 46 (0.41) 0 (0.00) Third trimester 933 (3.08) 933 (8.40) 0 (0.00) Positive PCR test status Positive during first 6 months of life 940 (3.10) 391 (3.52) 549 (2.86) Hospitalization status Hospitalized with positive PCR test during first 6 months of life 10 (0.03) 1 (<0.01) 9 (0.05) Table 2. Effectiveness of COVID-19 Vaccination During Pregnancy Against Infant SARS-CoV-2 Infection: Cohort design First 2 months of life First 4 months of life First 6 months of life Infant observation period by predominant SARS-CoV-2 variant, and mother’s vaccination status Positive test N Crude incidence rate 1 Adjusted 2 VE (95% CI) Positive test N Crude incidence rate 1 Adjusted 2 VE (95% CI) Positive test N Crude incidence rate 1 Adjusted 2 VE (95% CI) Delta period Unvaccinated during pregnancy 54 5.53 Reference 118 5.18 Reference 189 4.83 Reference Received ≥2 doses during pregnancy 8 0.74 85 (67,93) 27 1.38 64 (43,78) 38 1.55 57 (36,71) Omicron period Unvaccinated during pregnancy 54 17.02 Reference 138 18.13 Reference 297 20.93 Reference Received ≥2 doses during pregnancy 54 16.18 22 (-18,48) 178 17.34 14 (-10,32) 326 16.40 12 (-4,26) 1 Rate per 100 person-years 2 Adjusted for maternal age, race/ethnicity, neighborhood deprivation index quartile, insurance payor, KPNC facility, pre-pregnancy body mass index, diabetes, hypertension, parity, child age and preterm birth status VE= Vaccine effectiveness Table 3. Effectiveness of COVID-19 Vaccination During Pregnancy Against Infant SARS-CoV-2 Infection by Infant Age at Testing, Trimester of Vaccination during Pregnancy, and by Virus Variant: Cohort design. First 2 months of life First 4 months of life First 6 months of life Infant observation period by predominant SARS-CoV-2 variant, and mother’s vaccination status Positive test N Crude incidence rate 1 Adjusted 2 VE (95% CI) Positive test N Crude incidence rate 1 Adjusted 2 VE (95% CI) Positive test N Crude incidence rate 1 Adjusted 2 VE (95% CI) Delta period Unvaccinated during pregnancy 54 5.53 Reference 118 5.18 Reference 189 4.83 Reference Received ≥2 doses during pregnancy 2nd dose during 1st trimester 3 1.73 61 (-31,89) 4 1.81 48 (-54,82) 4 1.78 49 (-46,82) 2nd dose during 2nd trimester 2 0.42 91 (63,98) 11 1.39 60 (23,79) 11 1.23 65 (33,81) 2nd dose during 3rd trimester 3 0.69 87 (55,96) 12 1.28 70 (43,84) 23 1.72 54 (27,71) Omicron period Unvaccinated during pregnancy 54 17.02 Reference 138 18.13 Reference 297 20.93 Reference Received ≥2 doses during pregnancy 2nd dose during 1st trimester 26 15.67 26 (-22,56) 58 13.18 23 (-6,44) 86 12.23 19 (-3,37) 2nd dose during 2nd trimester 12 11.26 37 (-21,67) 72 19.74 5 (-28,29) 152 19.17 3 (-19,21) 2nd dose during 3rd trimester 16 26.12 -4 (-84,41) 48 21.64 12 (-23,37) 88 17.92 18 (-4,36) 1 Rate per 100 person-years 2 Adjusted for maternal age, race/ethnicity, neighborhood deprivation index quartile, insurance payor, KPNC facility, pre-pregnancy body mass index, diabetes, hypertension, parity, child age and preterm birth status VE=Vaccine effectiveness Additional Declarations Yes there is potential Competing Interest. Dr. Klein received research support from Pfizer for COVID vaccine clinical trials and research support from Pfizer, Merck, GSK, Sanofi Pasteur and Protein Science (now Sanofi Pasteur) for unrelated studies Supplementary Files SupplementalTable.docx Cite Share Download PDF Status: Published Journal Publication published 28 Feb, 2023 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2143552","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":144857226,"identity":"7a7d62ec-04d5-4ef0-b42e-3ac4f24b1efe","order_by":0,"name":"Ousseny Zerbo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA70lEQVRIiWNgGAWjYNADxgYGOQmStRiTriVxBiFF/BLpjz983HGYweAA+8PHlTts0mfObmB8XPELtxbJGTlmkjPPHGaQbGBINjx7Ji13tswBZsOzfbi1GNzIYWPmbTvMwM/AcEyyse1w7jyJBDbJxh58WtIff/4L1MLGwNj+E6glXY6wlgQDaUawLcxsjEAtCdIgLQ0/8Pil542ZZG9bOo9kMxuzZOOZNMOZcw42GzY24NbCzw4MsZ9t1nIGx9sffmzcYSMvcbv54MOGP7i1QEEzDwMzjC0BjB3GNoJa6pDY4OgnbMsoGAWjYBSMHAAAvPVP1zpgTWkAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-8380-6215","institution":"Kaiser Permanente Northern California, Vaccine Study Center","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Ousseny","middleName":"","lastName":"Zerbo","suffix":""},{"id":144857227,"identity":"5a32ccde-bdc4-423b-8a68-1f31a91a01aa","order_by":1,"name":"G. Thomas Ray","email":"","orcid":"","institution":"Kaiser Permanente Northern California, Vaccine Study Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"G.","middleName":"Thomas","lastName":"Ray","suffix":""},{"id":144857228,"identity":"5436b846-7178-466d-9a39-f919793e6276","order_by":2,"name":"Bruce Fireman","email":"","orcid":"","institution":"Kaiser Permanente Northern California, Vaccine Study Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Bruce","middleName":"","lastName":"Fireman","suffix":""},{"id":144857229,"identity":"d308c25a-7106-4a3e-8487-4966d2633587","order_by":3,"name":"Evan Layefsky","email":"","orcid":"","institution":"Kaiser Permanente Northern California, Vaccine Study Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Evan","middleName":"","lastName":"Layefsky","suffix":""},{"id":144857230,"identity":"d50a3ab6-1bf5-4afb-8ec1-05a47e5c52b4","order_by":4,"name":"Kristin Goddard","email":"","orcid":"","institution":"Kaiser Permanente Northern California, Vaccine Study Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Kristin","middleName":"","lastName":"Goddard","suffix":""},{"id":144857231,"identity":"e6e8cd45-f162-409b-98c4-f02917904863","order_by":5,"name":"Edwin Lewis","email":"","orcid":"","institution":"Kaiser Permanente Northern California, Vaccine Study Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Edwin","middleName":"","lastName":"Lewis","suffix":""},{"id":144857232,"identity":"7d4f0d05-54fd-4b03-8e1f-6d93c289dca9","order_by":6,"name":"Pat Ross","email":"","orcid":"","institution":"Kaiser Permanente Northern California, Vaccine Study Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Pat","middleName":"","lastName":"Ross","suffix":""},{"id":144857233,"identity":"c31908cd-9aa6-4c31-9aef-81116c285ef3","order_by":7,"name":"Saad Omer","email":"","orcid":"https://orcid.org/0000-0002-5383-3474","institution":"Yale University","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Saad","middleName":"","lastName":"Omer","suffix":""},{"id":144857234,"identity":"973e6b57-da6b-4fa7-a7ef-e11f7b567c80","order_by":8,"name":"Mara Greenberg","email":"","orcid":"","institution":"Obstetrics and Gynecology, Kaiser Permanente Northern California Oakland, Regional Perinatal Service Center, Kaiser Permanente Northern California, Santa Clara","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Mara","middleName":"","lastName":"Greenberg","suffix":""},{"id":144857235,"identity":"db19a394-e2dd-4061-96eb-ea1eeba0ae18","order_by":9,"name":"Nicola Klein","email":"","orcid":"","institution":"Kaiser Permanente Northern California, Vaccine Study Center","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Nicola","middleName":"","lastName":"Klein","suffix":""}],"badges":[],"createdAt":"2022-10-07 23:25:42","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2143552/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2143552/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41467-023-36547-4","type":"published","date":"2023-02-28T05:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":27943775,"identity":"0af48520-9790-4b87-97dd-192a467095b3","added_by":"auto","created_at":"2022-10-18 16:22:27","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":50347,"visible":true,"origin":"","legend":"\u003cp\u003eConstruction of study cohort. Children born at Kaiser Permanente Northern California from December 15, 2020, through May 31, 2022.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-2143552/v1/063a6e7d0ec6bbd3c6b4dae0.png"},{"id":33852216,"identity":"05f6031b-5700-4bf5-8d44-ea7238a2fa58","added_by":"auto","created_at":"2023-03-06 16:46:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":305558,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2143552/v1/998f733e-e5ce-4737-b9f2-1267fb77a889.pdf"},{"id":27943774,"identity":"a8d5e04b-1145-48bb-a6b4-31dc1721fc59","added_by":"auto","created_at":"2022-10-18 16:22:27","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":14759,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalTable.docx","url":"https://assets-eu.researchsquare.com/files/rs-2143552/v1/8bc2eeb3009ad68d13b25c05.docx"}],"financialInterests":"\u003cb\u003eYes\u003c/b\u003e there is potential Competing Interest.\nDr. Klein received research support from Pfizer for COVID vaccine clinical trials and research support from Pfizer, Merck, GSK, Sanofi Pasteur and Protein Science (now Sanofi Pasteur) for unrelated studies","formattedTitle":"Maternal SARS-CoV-2 Vaccination and Infant Protection Against SARS-CoV-2 During the First 6 Months of Life","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIn the US, as of the end of September 2022, almost 15 million children have tested positive for severe acute respiratory syndrome corona virus 2 (SARS-CoV-2), the virus that causes Coronavirus Disease 2019 (COVID-19). Children currently account for about 18.5% of reported COVID-19 cases in the US\u003csup\u003e1\u003c/sup\u003e. SARS-CoV-2 infection can lead to severe illnesses and hospitalizations in children and infants\u0026nbsp;\u003csup\u003e2-5\u003c/sup\u003e. During Omicron predominance, children aged \u0026lt;6 months accounted for 44% of hospitalizations among children ages 0 \u0026ndash; 4 years\u0026nbsp;\u003csup\u003e3\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eVaccination offers the best way to protect against COVID-19 and its complications. COVID-19 vaccines have demonstrated both high efficacy in clinical trials and high real-world effectiveness, especially against the original and Delta variant of the virus\u0026nbsp;\u003csup\u003e6-10\u003c/sup\u003e. \u0026nbsp;Real-world data suggest lower COVID-19 vaccine effectiveness against Omicron variants\u003csup\u003e11-14\u003c/sup\u003e. However, infants aged \u0026lt; 6 months are not currently eligible for any currently available COVID-19 vaccines and must rely on placentally acquired immunity from their mothers.\u003c/p\u003e\n\u003cp\u003eLike influenza and Tdap vaccines\u0026nbsp;\u003csup\u003e15,16\u003c/sup\u003e, data suggest that vaccination during pregnancy may protect infants who are not old enough to be vaccinated against COVID-19. Two recent epidemiological studies found that vaccination during pregnancy was associated with a reduced risk of SARS-CoV-2 infection in infants during their first 4 months of life and a reduced risk of hospitalization during the first 5 months of life\u003csup\u003e17,18\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe objective of this study was to further evaluate the effectiveness of at least 2 doses of mRNA COVID-19 vaccination during pregnancy for preventing SARS-CoV-2 infection in infants during the first 2, 4 and 6 months of life during the Delta and Omicron variant periods. We used two different study designs: a primary design using a cohort analysis in which infants of vaccinated pregnant persons were compared with infants of unvaccinated pregnant persons. In this design, we used Cox proportional hazards models with calendar days as the underlying scale to estimate hazard ratios and calculated vaccine effectiveness as 1 minus the hazard ratio. Secondarily, we used a Test Negative Design (TND), which is a case control study, to compare the odds of vaccination among mothers of infants who tested positive vs. the odds of vaccination among mothers of infants who tested negative. In this analysis, vaccine effectiveness was evaluated as 1 minus the odds ratio. The aim of the secondary design was to compare the results from the cohort and TND design.\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003e\u003cu\u003eDescriptive statistics and characteristics\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBetween December 15, 2020, and May 31,2022, we identified 62117 infants born at Kaiser Permanente Northern California (KPNC), an integrated health care delivery organization. Among these infants, we excluded 21918 (35.3%) based on maternal exclusion criteria and\u0026nbsp;10408 (16.0%) after applying infant exclusion criteria (Figure 1). The final study population included 30288 (48.8%) infants who were KPNC members at least 2 months after birth. The mean age at pregnancy onset was 31 years (standard deviation 4.66 years). Most mothers (66.15%) were between ages 25 and \u0026lt;35 years, and more than a quarter (27.26%) were of Asian race, 5.16% were Black, 24.45% were of Hispanic ethnicity and 37.57% were White. Among the infants in the cohort, 19179 (63.32%) of the mothers were unvaccinated during pregnancy, 1035 (3.42%) of the mothers received 1 dose of a mRNA COVID-19 vaccine, 9456 (31.22%) received 2 doses, and 618 (2.04%) received 3 doses during pregnancy (Table 1).\u003c/p\u003e\n\u003cp\u003eDuring the first 6 months of life, 940 (3.10%) infants tested positive for SARS-CoV-2 by polymerase chain reaction (PCR) test and 10 (0.03%) infants were hospitalized with a positive SARS-CoV-2 test.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eVaccine effectiveness: Primary design cohort analyses\u0026nbsp;\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;During the Delta dominant period, the crude incidences of testing positive for SARS-CoV-2 during the first 2, 4 and 6 months of life were lower among infants whose mothers received at least 2 doses of mRNA COVID-19 vaccines during pregnancy (0.74, 1.38, and 1.55 infants per 100 person years [PY], respectively) than those whose mothers were not vaccinated during pregnancy (5.53, 5.18, and 4.83 infants per 100 PYs, respectively).\u0026nbsp;After adjusting for covariates, vaccination during pregnancy significantly reduced risk of the infant testing SARS-CoV-2 positive by 85% (95% confidence interval [CI]: 67, 93) during the first 2 months of life, 64% (95% CI: 43, 78) during the first 4 months of life and 57% (95% CI: \u0026nbsp; 36,71) during the first 6 months of life (Table 2). During the Omicron dominant period, vaccination during pregnancy reduced the risk of the infant testing SARS-CoV-2 positive by 22% (95% CI: -18, 48) during the first 2 months of life, 14% (95% CI:\u0026nbsp;-10, 32) during the first 4 months of life, and 12% (95% CI: - 4, 26) during the first 6 months of life (Table 2).\u003c/p\u003e\n\u003cp\u003eIn supplemental analyses by trimester of vaccination, receipt of the second dose during the second and third trimester reduced the risk of infants testing SARS-CoV-2 positive during the Delta dominant period by 91% (95% CI: 63, 98) and 87% (95% CI: 55, 96), respectively, \u0026nbsp;during the first 2 months of life, by 60% (95% CI: 23, 79) and 70% (95% CI: 43, 84) during the first 4 months of life and by 65% (95% CI:33, 81) and 54% (95% CI: 27, 71) during the first 6 months of life (Table 3). We observed a similar pattern in vaccine effectiveness by trimester during the Omicron dominant period, however, estimates of vaccine effectiveness by trimester during the Omicron period were imprecise and much lower than during the Delta period (Table 3).\u003c/p\u003e\n\u003cp\u003eOver the entire study period, the crude rate of hospitalization with a SARS-CoV-2 positive test was lower during the first 6 months of life among infants whose mothers received at least 2 doses of mRNA COVID-19 vaccines during pregnancy compared with infants whose mothers were unvaccinated during pregnancy (21/100000 PY vs. 100/100000 PY). VE against hospitalization was not estimated because of the very small number of hospitalized cases.\u0026nbsp;There were only 1 hospitalized case among the children of vaccinated mothers and 9 hospitalized cases among the children of unvaccinated mothers (Table 1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cu\u003eSecondary analysis results using a test negative design (TND)\u003c/u\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn the TND, we estimated that during the Delta predominant period, maternal vaccination reduced the infant\u0026rsquo;s risk of testing SARS-CoV-2 positive by 98% (95% CI:75, 100) during the first 2 months of life, 72% (95% CI: 55, 83) during the first 4 months of life, and 63% (95% CI: 45, 75) during the first 6 months of life (Supplemental Table). During the Omicron dominant period, maternal vaccination reduced the infant\u0026rsquo;s risk of testing SARS-CoV-2 positive by 55% (95% CI: 15, 76) during the first 2 months of life, 37% (95% CI:12, 55) during the first 4 months of life, and 40% (95% CI: 25, 53) during the first 6 months of life (Supplemental Table).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this large study which included \u0026gt;30,000 infants, we found that receipt of at least 2 doses of mRNA COVID-19 vaccine during pregnancy was associated with a decreased risk of infants testing SARS-CoV-2 positive during their first 6 months of life.\u0026nbsp;Maternal vaccination reduced the infant\u0026rsquo;s risk of testing SARS-CoV-2 positive initially by 85% which decreased to 57% by 6 months of life in the Delta dominant period. However, vaccination during pregnancy was less effective at protecting infants against SARS-CoV-2 infection during the Omicron period. As infants aged, protection provided by maternal vaccination decreased during both periods.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAlthough the study was unable to directly estimate VE against hospitalization due to the small number of hospitalized cases, it found that over the entire study period, the incidence rate of hospitalization during the first 6 months of life was much lower among the infants whose mothers were vaccinated during pregnancy compared with those whose mothers were not vaccinated. These results suggest that in addition to providing protection against testing positive, vaccination during pregnancy may also provide protection against hospitalization (severe disease) in the infants during their first 6 months of life as previously reported recently\u003csup\u003e18\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eOur findings that vaccination during pregnancy was effective at protecting infants during the Delta period are similar to those reported in a recent Norwegian study showing that mRNA COVID-19 vaccination during pregnancy was associated with a 71% decreased risk of testing positive for SARS-CoV-2 in infants during their first 4 months of life during the Delta period\u0026nbsp;\u003csup\u003e17\u003c/sup\u003e. During the Delta period, we found that protection extended through the infant\u0026rsquo;s first 6 months of life. However, in contrast with the Norwegian study which reported that infants of mothers who were vaccinated had a 33% decreased risk of testing positive during the first 4 months of life during the Omicron period\u0026nbsp;\u003csup\u003e17\u003c/sup\u003e, our study found a 14% reduced risk that was not statistically significant. Difference between the two studies might be due to population characteristics and to the timing of follow up as ours went through May 31, 2022, while the Norwegian study\u0026rsquo;s ended in April 2022.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe finding that maternal vaccination was less effective at protecting infants during the Omicron dominant period is also consistent with previous studies which have reported decreased effectiveness of mRNA COVID-19 vaccines during Omicron among children and adults\u0026nbsp;\u003csup\u003e14,19\u003c/sup\u003e.\u0026nbsp;Recently another study reported that the effectiveness of mRNA COVID-19 vaccines against infections and hospitalizations among pregnant people was higher during the Delta period than during the Omicron period\u003csup\u003e20\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eWe observed that infant\u0026rsquo;s protection through vaccination during pregnancy decreased as they aged from 2 months to 6 months. These findings are consistent with diminishing of pregnancy derived antibodies in the infants over time\u003csup\u003e21\u003c/sup\u003e. A recent study found that the mean titer of maternally derived antibodies in infants of vaccinated mothers were higher at ages 2 months compared with antibody titers at ages 6 months\u0026nbsp;\u003csup\u003e22\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDespite several studies showing that vaccination during pregnancy is safe for pregnant people\u003csup\u003e\u0026nbsp;\u003c/sup\u003e\u003csup\u003e11-15\u003c/sup\u003e, vaccine uptake has been suboptimal in this group\u0026nbsp;\u003csup\u003e23\u003c/sup\u003e. In the present study, the mothers of only 33% of infants in the cohort received at least 2 doses. More efforts are needed to promote COVID-19 vaccines for pregnant persons because vaccination provides protection to mothers and their infants until they are old enough to receive their own COVID-19 vaccines.\u003c/p\u003e\n\u003cp\u003eOur study was strengthened both by its large sample size and our ability to follow infants through 6 months of age. In addition, our study period included two different SARV-CoV-2 variants, which allowed estimation of the effectiveness of vaccination during pregnancy in infants during both the Delta and Omicron variant periods. Our primary cohort analysis used calendar days as the underlying scale to ensure that we compared infants of vaccinated and unvaccinated mothers on the same calendar days because vaccination status during pregnancy and risk of SARS-CoV-2 infection varied over the study period. In this primary design, all eligible infants meeting inclusion criteria were included without sampling which improved power and minimized bias related to selection. Furthermore, it was reassuring that both the cohort and the secondary TND yielded vaccine effectiveness estimates in the same direction. Although both approaches adjusted for the same confounding factors, the effectiveness estimates from the TND were higher than those from the cohort design, which is consistent with our previous analyses of influenza vaccine effectiveness in which we also observed that the TND tended to result in higher vaccine effectiveness estimates than did our cohort analyses\u0026nbsp;\u003csup\u003e24\u003c/sup\u003e. The TND, a case control study, has been commonly used in studies of the effectiveness of influenza vaccines and more recently COVID-19 vaccines. It is designed to better adjust for healthcare seeking behavior\u0026nbsp;\u003csup\u003e25-27\u003c/sup\u003e, although it may also introduce other biases including selection bias\u0026nbsp;\u003csup\u003e28\u003c/sup\u003e.The TND used analysis limited to the sample of infants who were tested for SARS-CoV-2.\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;The study had limitations worth noting. Vaccinations were limited only to those received during pregnancy. We did not assess whether vaccines received before pregnancy or immediately after pregnancy were associated with reduced risk of testing positive for SARS-CoV-2 in infants.\u0026nbsp;The study did not adjust for maternal SARS-CoV-2 infections during pregnancy. During the study period, home testing became more prevalent. It is possible that this practice may have led to some misclassification of outcome, and we were unable to assess whether this misclassification was differential between vaccinated and unvaccinated mothers. We did not have genotyping data to confirm the variant that infected infants who tested positive and instead relied on state data regarding circulating strain predominance in the Northern California region. Like all observational studies, our study results are susceptible to residual confounding.\u003c/p\u003e\n\u003cp\u003eIn conclusion, in this population-based cohort study, we found that infants born to mothers who received at least 2 doses of a mRNA COVID-19 vaccine during pregnancy were at lower risk of testing positive for SARS-CoV-2 and were at lower risk of hospitalization during the first 6 months of life compared with infants whose mothers were unvaccinated during pregnancy. Maternal vaccination was protective, but protection was lower during the Omicron period than during Delta. Protection during both periods decreased as infants aged from 2 months to 6 months. Overall, the study results support recommendations for vaccination during pregnancy to protect both mothers and their infants.\u003c/p\u003e"},{"header":"Online Method","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eSetting and Study Population\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study setting was Kaiser Permanente Northern California (KPNC), an integrated healthcare delivery organization that provides comprehensive health care to approximately 4.4 million members as of 2019. Members receive almost all their medical care at KPNC-owned facilities, including clinics, hospitals, pharmacies, and laboratories. KPNC has a comprehensive electronic health record system that captures detailed information on all medical services, including immunization, membership enrollment including place of residence, demographics, and pregnancy related care from pregnancy onset to delivery and beyond. KPNC members are similar to the broad catchment population in Northern California in terms of sociodemographic characteristics\u0026nbsp;\u003csup\u003e29\u003c/sup\u003e. Annually, approximately 40,000 births occur at KPNC facilities.\u003c/p\u003e\n\u003cp\u003eThe study was conducted among a cohort of infants born between December 15, 2020, and May 31, 2022. From this cohort, the study excluded the following infants born to: 1) mothers who were not between ages 16 and 50 years at pregnancy onset; 2) mothers who did not have a primary KPNC facility assignment; 3) mothers who were not continuous KPNC members from December 15, 2020 until delivery \u0026nbsp;4) mothers who had a positive nasal/throat swab for SARS-CoV-2 by polymerase chain reaction (PCR) prior to pregnancy onset; 5) mothers who had a positive SARS-CoV-2 antibody test documented by KPNC prior to onset of pregnancy; 6) mothers who received one or more doses of COVID-19 vaccine prior to pregnancy onset. We excluded these infants because we were primarily interested in estimating the effectiveness of at least 2 doses of mRNA vaccines received during pregnancy; \u0026nbsp;7) mothers who received other COVID-19 vaccine than mRNA vaccine during pregnancy; \u0026nbsp;8) mothers who did not receive their mRNA vaccinations in accordance with CDC recommendations \u0026ndash; e.g., the timing between dose 1 and dose 2 was not within the recommended intervals; and 9) infants who did not become KPNC members within two calendar months of their birth. No other exclusion criteria were applied.\u003c/p\u003e\n\u003cp\u003eThe KPNC Institutional review board approved and waived consent for this study.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u0026nbsp;Outcomes \u0026nbsp;\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe outcomes were infant\u0026rsquo;s first positive nasal/throat swab for SARS-CoV-2 by PCR, and first COVID-19 related hospitalization, occurring during the first 6 months of life and recorded in the electronic health record.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eExposure\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe exposure of interest was mRNA COVID-19 vaccination status during pregnancy in the electronic health record. Mothers were classified as either having had \u0026ge; 2 doses of mRNA COVID-19 vaccines during pregnancy (and completed more than 7 days prior to delivery) or not having had any COVID-19 vaccines prior to delivery. We further classified vaccination status by the trimester within which the 2\u003csup\u003end\u003c/sup\u003e dose was received.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eCovariates\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor mothers of infants in the cohort we extracted from the electronic health record data: age at pregnancy onset, race/ethnicity (Asian, Black, Hispanic, Pacific Islander, Multiracial, Native American, Other, White), the primary KPNC facility at which the woman received most of their health care, insurance payor (dichotomized as \u0026ldquo;Medicare/Medicaid/other subsidized insurance\u0026rdquo; and \u0026ldquo;Other\u0026rdquo;), neighborhood deprivation index [NDI]\u0026nbsp;\u003csup\u003e30\u003c/sup\u003e categorized into quartiles with higher values representing greater deprivation), \u0026nbsp;pre-pregnancy body mass index (BMI=kg/m2; underweight \u0026lt;18.5, normal 18.5-24.9, overweight 25.0-29.9, obese \u0026ge;30.0), pre-pregnancy diabetes status, pre-pregnancy hypertension and parity (0, 1, 2, 3, \u0026ge;4). For infants, we included age, as a categorical time-changing variable in 30-day increments and preterm status defined as gestational age at birth less than 37 weeks.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStatistical analysis\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe conducted a descriptive analysis of the study population and calculated crude rates of SARS-CoV-2 infection and hospitalization by maternal vaccination status. In our primary analysis, we implemented a cohort study design where\u0026nbsp;we used Cox proportional hazards models\u0026nbsp;that allow for time-varying covariates to estimate the SARS-CoV-2 infection hazard ratio (HR) in infants of mothers vaccinated with at least 2 doses of mRNA COVID-19 vaccines during pregnancy versus mothers who were unvaccinated during pregnancy.\u0026nbsp;We calculated vaccine effectiveness (VE) as 100% multiplied by 1 \u0026ndash; HR. In all models, we used calendar days as the time scale to account for changes over time in SARS-CoV-2 circulation and vaccine uptake. Infants\u0026nbsp;were followed from birth until first positive SARS-CoV-2 test by PCR at age 2, 4 or 6 months, with censoring due to death, health plan disenrollment, or end of follow-up (May 31, 2022). Models were adjusted for covariates listed above.\u0026nbsp;To account for the correlation between infants with the same mother, we fit marginal Cox proportional hazards models using robust sandwich variance estimates.\u0026nbsp;We ran separate models on the time periods associated with\u0026nbsp;the Delta (7/01/2021 to 12/20/2021) and Omicron variants (12/21/2021 to 5/31/2022). We also conducted analyses based on the trimester during which the vaccine was received during pregnancy (first, second or third trimester).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe conducted secondary sensitivity analyses restricting the population to infants who received at least one SARS-CoV-2 PCR test. In this analysis, we estimated the odds ratio (OR) of vaccination of mothers of infants who tested positive for SARS-CoV-2 versus infants who tested negative using logistic regression models conditioned (stratified) on the calendar date of the test so that infants testing positive on a certain day were compared to infants testing negative on that same day. We calculated VE as 100% multiplied by 1- OR. This case-positive, control-test-negative design also referred to as the test negative design (TND) has often been used in studies of vaccine effectiveness. The TND is designed to better control for bias related to health care seeking behavior\u0026nbsp;\u003csup\u003e25-27\u003c/sup\u003e. Models in this analysis were adjusted for the same covariates included in the primary analysis. All analyses were conducted using SAS software, v9.4. and statistical significance was assessed at two-sided p\u0026le;0.05.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eFunding Source: The study was funded by the National Institute of Allergy and Infectious Disease grant # 1R01AI168373-01\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAmerican, Academy, of, et al. Children and COVID-19:State Data Report. A joint report from the American Academy of Pediatrics and the Children\u0026rsquo;s Hospital Association. Accessed October 5, 2022, https://downloads.aap.org/AAP/PDF/AAP%20and%20CHA%20-%20Children%20and%20COVID-19%20State%20Data%20Report%209.29.22%20FINAL.pdf?_ga=2.255000394.335550773.1665001859-370326403.1636740765\u003c/li\u003e\n \u003cli\u003eGraff K, Smith C, Silveira L, et al. Risk Factors for Severe COVID-19 in Children. \u003cem\u003ePediatr Infect Dis J\u003c/em\u003e. Apr 1 2021;40(4):e137-e145. doi:10.1097/INF.0000000000003043\u003c/li\u003e\n \u003cli\u003eMarks KJ, Whitaker M, Agathis NT, et al. Hospitalization of Infants and Children Aged 0-4 Years with Laboratory-Confirmed COVID-19 - COVID-NET, 14 States, March 2020-February 2022. \u003cem\u003eMMWR Morb Mortal Wkly Rep\u003c/em\u003e. Mar 18 2022;71(11):429-436. doi:10.15585/mmwr.mm7111e2\u003c/li\u003e\n \u003cli\u003eHobbs CV, Woodworth K, Young CC, et al. Frequency, Characteristics and Complications of COVID-19 in Hospitalized Infants. \u003cem\u003ePediatr Infect Dis J\u003c/em\u003e. Mar 1 2022;41(3):e81-e86. doi:10.1097/INF.0000000000003435\u003c/li\u003e\n \u003cli\u003eKim L, Whitaker M, O\u0026apos;Halloran A, et al. Hospitalization Rates and Characteristics of Children Aged \u0026lt;18 Years Hospitalized with Laboratory-Confirmed COVID-19 - COVID-NET, 14 States, March 1-July 25, 2020. \u003cem\u003eMMWR Morb Mortal Wkly Rep\u003c/em\u003e. Aug 14 2020;69(32):1081-1088. doi:10.15585/mmwr.mm6932e3\u003c/li\u003e\n \u003cli\u003eBaden LR, El Sahly HM, Essink B, et al. Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine. \u003cem\u003eN Engl J Med\u003c/em\u003e. Feb 4 2021;384(5):403-416. doi:10.1056/NEJMoa2035389\u003c/li\u003e\n \u003cli\u003ePolack FP, Thomas SJ, Kitchin N, et al. Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. \u003cem\u003eN Engl J Med\u003c/em\u003e. Dec 31 2020;383(27):2603-2615. doi:10.1056/NEJMoa2034577\u003c/li\u003e\n \u003cli\u003eSadoff J, Gray G, Vandebosch A, et al. Safety and Efficacy of Single-Dose Ad26.COV2.S Vaccine against Covid-19. \u003cem\u003eN Engl J Med\u003c/em\u003e. Jun 10 2021;384(23):2187-2201. doi:10.1056/NEJMoa2101544\u003c/li\u003e\n \u003cli\u003eDagan N, Barda N, Kepten E, et al. BNT162b2 mRNA Covid-19 Vaccine in a Nationwide Mass Vaccination Setting. \u003cem\u003eN Engl J Med\u003c/em\u003e. Apr 15 2021;384(15):1412-1423. doi:10.1056/NEJMoa2101765\u003c/li\u003e\n \u003cli\u003eThompson MG, Stenehjem E, Grannis S, et al. Effectiveness of Covid-19 Vaccines in Ambulatory and Inpatient Care Settings. \u003cem\u003eN Engl J Med\u003c/em\u003e. Oct 7 2021;385(15):1355-1371. doi:10.1056/NEJMoa2110362\u003c/li\u003e\n \u003cli\u003eBuchan SA, Chung H, Brown KA, et al. Estimated Effectiveness of COVID-19 Vaccines Against Omicron or Delta Symptomatic Infection and Severe Outcomes. \u003cem\u003eJAMA Netw Open\u003c/em\u003e. Sep 1 2022;5(9):e2232760. doi:10.1001/jamanetworkopen.2022.32760\u003c/li\u003e\n \u003cli\u003eCohen-Stavi CJ, Magen O, Barda N, et al. BNT162b2 Vaccine Effectiveness against Omicron in Children 5 to 11 Years of Age. \u003cem\u003eN Engl J Med\u003c/em\u003e. Jul 21 2022;387(3):227-236. doi:10.1056/NEJMoa2205011\u003c/li\u003e\n \u003cli\u003eFerdinands JM, Rao S, Dixon BE, et al. Waning 2-Dose and 3-Dose Effectiveness of mRNA Vaccines Against COVID-19-Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Adults During Periods of Delta and Omicron Variant Predominance - VISION Network, 10 States, August 2021-January 2022. \u003cem\u003eMMWR Morb Mortal Wkly Rep\u003c/em\u003e. Feb 18 2022;71(7):255-263. doi:10.15585/mmwr.mm7107e2\u003c/li\u003e\n \u003cli\u003eKlein NP, Stockwell MS, Demarco M, et al. Effectiveness of COVID-19 Pfizer-BioNTech BNT162b2 mRNA Vaccination in Preventing COVID-19-Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Nonimmunocompromised Children and Adolescents Aged 5-17 Years - VISION Network, 10 States, April 2021-January 2022. \u003cem\u003eMMWR Morb Mortal Wkly Rep\u003c/em\u003e. Mar 4 2022;71(9):352-358. doi:10.15585/mmwr.mm7109e3\u003c/li\u003e\n \u003cli\u003eBaxter R, Bartlett J, Fireman B, Lewis E, Klein NP. Effectiveness of Vaccination During Pregnancy to Prevent Infant Pertussis. \u003cem\u003ePediatrics\u003c/em\u003e. May 2017;139(5)doi:10.1542/peds.2016-4091\u003c/li\u003e\n \u003cli\u003eFoo D, Sarna M, Pereira G, Moore HC, Regan AK. Longitudinal, population-based cohort study of prenatal influenza vaccination and influenza infection in childhood. \u003cem\u003eVaccine\u003c/em\u003e. Jan 28 2022;40(4):656-665. doi:10.1016/j.vaccine.2021.11.084\u003c/li\u003e\n \u003cli\u003eCarlsen EO, Magnus MC, Oakley L, et al. Association of COVID-19 Vaccination During Pregnancy With Incidence of SARS-CoV-2 Infection in Infants. \u003cem\u003eJAMA Intern Med\u003c/em\u003e. Aug 1 2022;182(8):825-831. doi:10.1001/jamainternmed.2022.2442\u003c/li\u003e\n \u003cli\u003eHalasa NB, Olson SM, Staat MA, et al. Maternal Vaccination and Risk of Hospitalization for Covid-19 among Infants. \u003cem\u003eN Engl J Med\u003c/em\u003e. Jul 14 2022;387(2):109-119. doi:10.1056/NEJMoa2204399\u003c/li\u003e\n \u003cli\u003eAndrews N, Stowe J, Kirsebom F, et al. Covid-19 Vaccine Effectiveness against the Omicron (B.1.1.529) Variant. \u003cem\u003eN Engl J Med\u003c/em\u003e. Apr 21 2022;386(16):1532-1546. doi:10.1056/NEJMoa2119451\u003c/li\u003e\n \u003cli\u003eSchrag SJ, Verani JR, Dixon BE, et al. Estimation of COVID-19 mRNA Vaccine Effectiveness Against Medically Attended COVID-19 in Pregnancy During Periods of Delta and Omicron Variant Predominance in the United States. \u003cem\u003eJAMA Netw Open\u003c/em\u003e. Sep 1 2022;5(9):e2233273. doi:10.1001/jamanetworkopen.2022.33273\u003c/li\u003e\n \u003cli\u003eVoysey M, Pollard AJ, Sadarangani M, Fanshawe TR. Prevalence and decay of maternal pneumococcal and meningococcal antibodies: A meta-analysis of type-specific decay rates. \u003cem\u003eVaccine\u003c/em\u003e. Oct 13 2017;35(43):5850-5857. doi:10.1016/j.vaccine.2017.09.002\u003c/li\u003e\n \u003cli\u003eShook LL, Atyeo CG, Yonker LM, et al. Durability of Anti-Spike Antibodies in Infants After Maternal COVID-19 Vaccination or Natural Infection. \u003cem\u003eJAMA\u003c/em\u003e. Mar 15 2022;327(11):1087-1089. doi:10.1001/jama.2022.1206\u003c/li\u003e\n \u003cli\u003eRazzaghi H, Meghani M, Pingali C, et al. COVID-19 Vaccination Coverage Among Pregnant Women During Pregnancy - Eight Integrated Health Care Organizations, United States, December 14, 2020-May 8, 2021. \u003cem\u003eMMWR Morb Mortal Wkly Rep\u003c/em\u003e. Jun 18 2021;70(24):895-899. doi:10.15585/mmwr.mm7024e2\u003c/li\u003e\n \u003cli\u003eKlein NP, Fireman B, Goddard K, et al. Vaccine effectiveness of cell-culture relative to egg-based inactivated influenza vaccine during the 2017-18 influenza season. \u003cem\u003ePLoS One\u003c/em\u003e. 2020;15(2):e0229279. doi:10.1371/journal.pone.0229279\u003c/li\u003e\n \u003cli\u003eFoppa IM, Haber M, Ferdinands JM, Shay DK. The case test-negative design for studies of the effectiveness of influenza vaccine. \u003cem\u003eVaccine\u003c/em\u003e. Jun 26 2013;31(30):3104-9. doi:10.1016/j.vaccine.2013.04.026\u003c/li\u003e\n \u003cli\u003eJackson ML, Nelson JC. The test-negative design for estimating influenza vaccine effectiveness. \u003cem\u003eVaccine\u003c/em\u003e. Apr 19 2013;31(17):2165-8. doi:10.1016/j.vaccine.2013.02.053\u003c/li\u003e\n \u003cli\u003eCoulton BL, Thomson K, Symmons DP, Popert AJ. Outcome in patients hospitalised for psoriatic arthritis. \u003cem\u003eClin Rheumatol\u003c/em\u003e. Jun 1989;8(2):261-5. doi:10.1007/BF02030083\u003c/li\u003e\n \u003cli\u003eAinslie KEC, Shi M, Haber M, Orenstein WA. On the bias of estimates of influenza vaccine effectiveness from test-negative studies. \u003cem\u003eVaccine\u003c/em\u003e. Dec 19 2017;35(52):7297-7301. doi:10.1016/j.vaccine.2017.10.107\u003c/li\u003e\n \u003cli\u003eGordon N, Lin T. The Kaiser Permanente Northern California Adult Member Health Survey. \u003cem\u003ePerm J\u003c/em\u003e. Fall 2016;20(4):15-225. doi:10.7812/TPP/15-225\u003c/li\u003e\n \u003cli\u003eMesser LC, Laraia BA, Kaufman JS, et al. The development of a standardized neighborhood deprivation index. \u003cem\u003eJ Urban Health\u003c/em\u003e. Nov 2006;83(6):1041-62. doi:10.1007/s11524-006-9094-x\u003cins cite=\"mailto:Evan%20Layefsky\" datetime=\"2022-10-07T15:56\"\u003e\u003c/ins\u003e\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1. Characteristics of the Study Population: Infants Born at Kaiser Permanente Northern California December 15, 2020 \u0026ndash; May 31, 2022.\u003c/p\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"623\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003eCharacteristics\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003eInfants included in the study\u003c/p\u003e\n \u003cp\u003eN=30,288\u003c/p\u003e\n \u003cp\u003en(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003eInfants whose mothers were vaccinated during pregnancy N=11,109\u003c/p\u003e\n \u003cp\u003en(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003eInfants whose mothers were not vaccinated during pregnancy N=19,179\u003c/p\u003e\n \u003cp\u003en(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003eMaternal age at pregnancy onset (years), mean (std)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e31.62 (4.66)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e32.59 (4.31)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e31.06 (4.76)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003eMaternal age category (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; 16 - \u0026lt; 25 \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e2,092 (6.91)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e393 (3.54)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e1,699 (8.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; 25 - \u0026lt;35\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e20,036 (66.15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e7,047(63.44)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e12,989 (67.73)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; 35 - \u0026lt;50 \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e8,160(26.94)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e3,669(33.03)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e4,491(23.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003eMaternal race/ethnicity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Asian\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e8,255 (27.26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e3,741 (33.68)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e4,514 (23.54)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Black\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e1,564 (5.16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e373 (3.36)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e1,191 (6.21)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Hispanic\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e7,405 (24.45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e2,198 (19.79)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e5,207 (27.15)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Pacific Islander\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e246 (0.81)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e74 (0.67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e172 (0.90)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Multiracial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e108 (0.36)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e37 (0.33)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e71 (0.37)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Native American\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e764 (2.52)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e289 (2.60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e475 (2.48)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; Other/unknown/multi-racial\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e566 (1.87)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e227 (2.04)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e339 (1.77)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;White\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e11,380 (37.57)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e4,170 (37.54)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e7,210 (37.59)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003eParity, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e12,084 (39.90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e4,809 (43.29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e7,275 (37.93)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e11,180 (36.91)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e4,259 (38.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e6,921 (36.09)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e3,921 (12.95)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e1,171 (10.54)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e2,750 (14.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e1,212 (4.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e279 (2.51)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e933 (4.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;4+\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e576 (1.90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e130 (1.17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e446 (2.33)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; Unknown\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e1,315 (4.34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e461 (4.15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e854 (4.45)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003eMedical comorbidity before pregnancy, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Diabetes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e490 (1.62)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e221 (1.99)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e269 (1.40)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Hypertension\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e2,469 (8.15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e916 (8.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e1,553 (8.10)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003eBody Mass Index\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Underweight\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e658 (2.17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e272 (2.45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e386 (2.01)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Normal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e12,478 (41.20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e4,870 (43.84)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e7,608 (39.67)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Overweight\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e8,840 (29.19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e3,127 (28.15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e5,713 (29.79)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Obese\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e8,206 (27.09)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e2,805 (25.25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e5,401 (28.16)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Unknown\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e106 (0.35)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e35 (0.32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e71 (0.37)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003eType of insurance\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Subsidized (Medicare/Medicaid/other subsidized insurance)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e2,007 (6.63)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e460 (4.14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e1,547 (8.07)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Non-subsidized\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e28,281(93.37)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e10,649 (95.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e17,632 (91.93)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"63.402889245585875%\"\u003e\n \u003cp\u003eNeighborhood Deprivation Index (quartile), n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.459069020866774%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.13804173354735%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;First quartile 1 (least deprived)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e7,481 (24.70)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e3,651 (32.87)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e3,830 (19.97)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Second quartile\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e8,101 (26.75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e3,010 (27.10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e5,091 (26.54)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Third quartile\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e7,257 (23.96)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e2,379 (21.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e4,878 (25.43)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Fourth quartile (most deprived)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e7,396 (24.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e2,046 (18.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e5,350 (27.90)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Missing\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e53 (0.17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e23 (0.21)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e30 (0.16)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003ePreterm birth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e2,256 (7.45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e775 (6.98)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e1,481 (7.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003emRNA COVID-19 vaccine doses\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; 0 dose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e19,179 (63.32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e19,179 (100)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; 1 dose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e1,035 (3.42)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e1,035 (9.32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; 2 doses\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e9,456 (31.22)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e9,456 (85.12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; 3 doses\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e618 (2.04)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e618 (5.56)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Gestational age at COVID-19 vaccination for second dose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; First trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e2,081 (6.87)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e2,081(18.73)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Second trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e3,669 (12.11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e3,669 (33.03)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Third trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e4,324 (14.28)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e4,324 (38.92)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Gestational age at COVID-19 vaccination for those who only had one dose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; First trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e56 (0.18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e56 (0.50)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Second trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e46 (0.15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e46 (0.41)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Third trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e933 (3.08)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e933 (8.40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e0 (0.00)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003ePositive PCR test status\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Positive during first 6 months of life\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e940 (3.10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e391 (3.52)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e549 (2.86)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003eHospitalization status\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"45.81993569131833%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Hospitalized with positive PCR test during first 6 months of life\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"17.524115755627008%\"\u003e\n \u003cp\u003e10 (0.03)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.488745980707396%\"\u003e\n \u003cp\u003e1 (\u0026lt;0.01)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"18.167202572347268%\"\u003e\n \u003cp\u003e9 (0.05)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTable 2. Effectiveness of COVID-19 Vaccination During Pregnancy Against Infant SARS-CoV-2 Infection: Cohort design\u003c/p\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"954\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"27.044025157232703%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"bottom\" width=\"24.528301886792452%\"\u003e\n \u003cp\u003eFirst 2 months of life\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"bottom\" width=\"24.0041928721174%\"\u003e\n \u003cp\u003eFirst 4 months of life\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"bottom\" width=\"24.42348008385744%\"\u003e\n \u003cp\u003eFirst 6 months of life\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"27.044025157232703%\"\u003e\n \u003cp\u003eInfant observation period by predominant SARS-CoV-2 variant, and mother\u0026rsquo;s vaccination status\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003ePositive test\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.861635220125786%\"\u003e\n \u003cp\u003eCrude incidence rate\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.748427672955975%\"\u003e\n \u003cp\u003eAdjusted\u003csup\u003e2\u003c/sup\u003e VE (95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003ePositive test\u003c/p\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.547169811320755%\"\u003e\n \u003cp\u003eCrude incidence rate\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.538784067085954%\"\u003e\n \u003cp\u003eAdjusted\u003csup\u003e2\u003c/sup\u003e VE (95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.60377358490566%\"\u003e\n \u003cp\u003ePositive test\u003c/p\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.385744234800839%\"\u003e\n \u003cp\u003eCrude incidence rate\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.433962264150944%\"\u003e\n \u003cp\u003eAdjusted\u003csup\u003e2\u003c/sup\u003e VE (95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"27.044025157232703%\"\u003e\n \u003cp\u003eDelta period\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.861635220125786%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.748427672955975%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.547169811320755%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.538784067085954%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.60377358490566%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.385744234800839%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.433962264150944%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"27.044025157232703%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Unvaccinated during pregnancy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.861635220125786%\"\u003e\n \u003cp\u003e5.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.748427672955975%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003e118\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.547169811320755%\"\u003e\n \u003cp\u003e5.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.538784067085954%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.60377358490566%\"\u003e\n \u003cp\u003e189\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.385744234800839%\"\u003e\n \u003cp\u003e4.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.433962264150944%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"27.044025157232703%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Received \u0026ge;2 doses during pregnancy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.861635220125786%\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.748427672955975%\"\u003e\n \u003cp\u003e85 (67,93)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.547169811320755%\"\u003e\n \u003cp\u003e1.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.538784067085954%\"\u003e\n \u003cp\u003e64 (43,78)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.60377358490566%\"\u003e\n \u003cp\u003e38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.385744234800839%\"\u003e\n \u003cp\u003e1.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.433962264150944%\"\u003e\n \u003cp\u003e57 (36,71)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"27.044025157232703%\"\u003e\n \u003cp\u003eOmicron period\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.861635220125786%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.748427672955975%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.547169811320755%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.538784067085954%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.60377358490566%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.385744234800839%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.433962264150944%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"27.044025157232703%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Unvaccinated during pregnancy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.861635220125786%\"\u003e\n \u003cp\u003e17.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.748427672955975%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003e138\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.547169811320755%\"\u003e\n \u003cp\u003e18.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.538784067085954%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.60377358490566%\"\u003e\n \u003cp\u003e297\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.385744234800839%\"\u003e\n \u003cp\u003e20.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.433962264150944%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"27.044025157232703%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp;Received \u0026ge;2 doses during pregnancy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.861635220125786%\"\u003e\n \u003cp\u003e16.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.748427672955975%\"\u003e\n \u003cp\u003e22 (-18,48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.918238993710692%\"\u003e\n \u003cp\u003e178\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.547169811320755%\"\u003e\n \u003cp\u003e17.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.538784067085954%\"\u003e\n \u003cp\u003e14 (-10,32)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.60377358490566%\"\u003e\n \u003cp\u003e326\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.385744234800839%\"\u003e\n \u003cp\u003e16.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.433962264150944%\"\u003e\n \u003cp\u003e12 (-4,26)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"10\" valign=\"bottom\" width=\"100%\"\u003e\n \u003cp\u003e\u003csup\u003e1\u003c/sup\u003eRate per 100 person-years\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e2\u003c/sup\u003eAdjusted for maternal age, race/ethnicity, neighborhood deprivation index quartile, insurance payor, KPNC facility, pre-pregnancy body mass index, diabetes, hypertension, parity, child age and preterm birth status\u003c/p\u003e\n \u003cp\u003eVE= Vaccine effectiveness\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTable 3. Effectiveness of COVID-19 Vaccination During Pregnancy Against Infant SARS-CoV-2 Infection by Infant Age at Testing, Trimester of Vaccination during Pregnancy, and by Virus Variant: Cohort design.\u003c/p\u003e\n\u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"984\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"bottom\" width=\"24.390243902439025%\"\u003e\n \u003cp\u003eFirst 2 months of life\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"bottom\" width=\"23.577235772357724%\"\u003e\n \u003cp\u003eFirst 4 months of life\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"bottom\" width=\"26.422764227642276%\"\u003e\n \u003cp\u003eFirst 6 months of life\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003eInfant observation period by predominant SARS-CoV-2 variant, and mother\u0026rsquo;s vaccination status\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003ePositive test\u003c/p\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\n \u003cp\u003eCrude incidence rate\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003eAdjusted\u003csup\u003e2\u003c/sup\u003e VE (95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003ePositive test\u003c/p\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\n \u003cp\u003eCrude incidence rate\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003eAdjusted\u003csup\u003e2\u003c/sup\u003e VE (95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\n \u003cp\u003ePositive test\u003c/p\u003e\n \u003cp\u003eN\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\n \u003cp\u003eCrude incidence rate\u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\n \u003cp\u003eAdjusted\u003csup\u003e2\u003c/sup\u003e VE (95% CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003eDelta period\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Unvaccinated during pregnancy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\n \u003cp\u003e5.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e118\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\n \u003cp\u003e5.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\n \u003cp\u003e189\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\n \u003cp\u003e4.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Received \u0026ge;2 doses during pregnancy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; 2nd dose during 1st trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\n \u003cp\u003e1.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e61 (-31,89)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\n \u003cp\u003e1.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e48 (-54,82)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\n \u003cp\u003e1.78\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\n \u003cp\u003e49 (-46,82)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; 2nd dose during 2nd trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\n \u003cp\u003e0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e91 (63,98)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\n \u003cp\u003e1.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e60 (23,79)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\n \u003cp\u003e1.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\n \u003cp\u003e65 (33,81)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; 2nd dose during 3rd trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\n \u003cp\u003e0.69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e87 (55,96)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\n \u003cp\u003e1.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e70 (43,84)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\n \u003cp\u003e23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\n \u003cp\u003e1.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\n \u003cp\u003e54 (27,71)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003eOmicron period\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Unvaccinated during pregnancy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\n \u003cp\u003e17.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e138\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\n \u003cp\u003e18.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\n \u003cp\u003e297\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\n \u003cp\u003e20.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\n \u003cp\u003eReference\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; Received \u0026ge;2 doses during pregnancy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; 2nd dose during 1st trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\n \u003cp\u003e15.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e26 (-22,56)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\n \u003cp\u003e13.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e23 (-6,44)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\n \u003cp\u003e86\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\n \u003cp\u003e12.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\n \u003cp\u003e19 (-3,37)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; 2nd dose during 2nd trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\n \u003cp\u003e11.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e37 (-21,67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\n \u003cp\u003e19.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e5 (-28,29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\n \u003cp\u003e152\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\n \u003cp\u003e19.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\n \u003cp\u003e3 (-19,21)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" width=\"25.609756097560975%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; 2nd dose during 3rd trimester\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.536585365853659%\"\u003e\n \u003cp\u003e26.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e-4 (-84,41)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.7073170731707314%\"\u003e\n \u003cp\u003e48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"7.723577235772358%\"\u003e\n \u003cp\u003e21.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"9.146341463414634%\"\u003e\n \u003cp\u003e12 (-23,37)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"6.9105691056910565%\"\u003e\n \u003cp\u003e88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" width=\"8.130081300813009%\"\u003e\n \u003cp\u003e17.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"bottom\" width=\"11.382113821138212%\"\u003e\n \u003cp\u003e18 (-4,36)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"11\" valign=\"bottom\" width=\"100%\"\u003e\n \u003cp\u003e\u003csup\u003e1\u003c/sup\u003eRate per 100 person-years\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e2\u003c/sup\u003eAdjusted for maternal age, race/ethnicity, neighborhood deprivation index quartile, insurance payor, KPNC facility, pre-pregnancy body mass index, diabetes, hypertension, parity, child age and preterm birth status\u003c/p\u003e\n \u003cp\u003eVE=Vaccine effectiveness\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-2143552/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2143552/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"We examined the effectiveness of maternal vaccination against SARS-CoV-2 infection in 30,288 infants born at Kaiser Permanente Northern California from December 15, 2020, to May 31, 2022. Using Cox regression, the effectiveness of maternal vaccination was 85% (95% confidence interval [CI]: 67, 93), 64% (CI: 43, 78) and 57% (CI: 36,71) during the first 2, 4 and 6 months of life, respectively, in the Delta variant period. In the Omicron variant period, the effectiveness of maternal vaccination in these three age intervals was 22% (CI: -18,48), 14% (CI: -10,32) and 12% (CI: -4,26), respectively. Over the entire study period, the incidence of hospitalization for COVID-19 was lower during the first 6 months of life among infants of vaccinated mothers compared with infants of unvaccinated mothers (21/100,000 person-years vs. 100/100,000 person-years). Maternal vaccination was protective, but protection was lower during Omicron than during Delta. Protection during both periods decreased as infants aged.","manuscriptTitle":"Maternal SARS-CoV-2 Vaccination and Infant Protection Against SARS-CoV-2 During the First 6 Months of Life","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-10-18 16:22:25","doi":"10.21203/rs.3.rs-2143552/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"bb696b49-cbab-4d24-99e4-7bdaa9c8e2f8","owner":[],"postedDate":"October 18th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[{"value":"featured","date":"2022-10-21 18:50:33"}],"updatedAt":"2023-03-06T16:45:43+00:00","versionOfRecord":{"articleIdentity":"rs-2143552","link":"https://doi.org/10.1038/s41467-023-36547-4","journal":{"identity":"nature-communications","isVorOnly":false,"title":"Nature Communications"},"publishedOn":"2023-02-28 05:00:00","publishedOnDateReadable":"February 28th, 2023"},"versionCreatedAt":"2022-10-18 16:22:25","video":"","vorDoi":"10.1038/s41467-023-36547-4","vorDoiUrl":"https://doi.org/10.1038/s41467-023-36547-4","workflowStages":[]},"version":"v1","identity":"rs-2143552","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2143552","identity":"rs-2143552","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}