A Cross sectional Observational Study of Safety and Protective Effects of Maternal Influenza Vaccination on Pregnancy and Birth Outcomes in pregnant women from Pune, India

Background: Maternal influenza vaccination provides effective protection against influenza in-fections in pregnant women and new-borns. In India, the influenza vaccine has not yet been of-fered through immunization programs, owing to the lack of sufficient safety data for Indian pregnant women. Methods: This cross-sectional observational study enrolled 558 women ad-mitted to the obstetrics ward of a civic hospital in Pune. Study-related information was obtained from the participants through interviews using structured questionnaires and hospital records. Univariate and multivariate analysis were used and chi-square with unadjusted and adjusted odds ratio were estimated to account for vaccine exposure and the temporal nature of each out-come, respectively. Results: The protective effect of maternal influenza vaccination against delivering very low birth weight infants was observed. (aOR 2.29, 95% CI 1.03 to 5.58, p=0.03). No association was observed between maternal influenza vaccination for spontaneous abortion (OR 1.42, 95%CI 0.75, 2.68), chorioamnionitis (OR 0.60, 95% CI, 0.1, 3.63), gestational hypertension (OR 1.73, 95% CI 0.72, 4.16) and preterm birth (OR 1.64, 95% CI 0.91, 2.97). Interpretation: These results show that the in-fluenza vaccine administered during pregnancy is safe and has a lower risk of negative birth outcomes.