Low prevalence of current and past SARS-CoV-2 infections among visitors and staff members of homelessness services in Amsterdam at the end of the second wave of infections in the Netherlands

Low prevalence of current and past SARS-CoV-2 infections among visitors and staff members of homelessness services in Amsterdam at the end of the second wave of infections in the Netherlands | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Low prevalence of current and past SARS-CoV-2 infections among visitors and staff members of homelessness services in Amsterdam at the end of the second wave of infections in the Netherlands Ellen Generaal, Daniela van Santen, Sophie Campman, Marjolein Booij, and 9 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1949434/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background People experiencing homelessness (PEH) may be at increased risk of SARS-CoV-2 infection and severe COVID-19. The Dutch government established emergency shelters and introduced preventive measures for homelessness services and there were no major SARS-CoV-2 outbreak noticed among PEH during the first two waves of infections. This study aimed to assess the prevalence of current and past infections among PEH and staff at the end of the second COVID-19 wave by conducting an on-site COVID-19 screening project at homelessness services in Amsterdam, the Netherlands. Methods We assessed the proportion of visitors and staff members of four homelessness services at two locations in Amsterdam with positive SARS-CoV-2 qPCR and antibody results (IgG/IgM Rapid Test, Biozek) in May 2021. We also assessed sociodemographic, clinical and lifestyle characteristics, compliance with basic prevention measures and intention to vaccinate against COVID-19 among PEH and staff. Results A total of 138 visitors and 53 staff members filled out a questionnaire and were tested. Among PEH, the SARS-CoV-2 positivity rate was 0% (0/133;95%CI=0-1.9) and the antibody positivity rate was 1.6% (2/131;95%CI=0.8-7.5). Among staff, these percentages were 3% (1/32;95%CI=0.1-16.2) and 11% (5/53;95%CI=3.6-23.6), respectively. Most participants were frequently compliant with the basic preventive measures ‘not shaking hands’, ‘wearing a face mask’ and ‘washing hands’, but not with ‘physical distancing’. Overall, intention to vaccinate for COVID-19 was low (30% for visitors, 10% for staff) or medium (28% for visitors, 35% for staff). Trust in COVID-19 policies were also, for the most part, low (27% for visitors, 17% for staff) or neutral (32% for visitors, 53% for staff). Conclusions We observed a low prevalence of past and current SARS-CoV-2 infections among PEH, which may be explained by instated shelter policies, limited daily activities of PEH and compliance with certain prevention measures. Vaccine hesitancy and mistrust among visitors and staff could hinder vaccination uptake, suggesting that improvements in public heath communication and interventions towards visitors and staff of homelessness services are needed. homeless persons shelters COVID-19 SARS-CoV-2 COVID-19 testing SARS-CoV-2 antibodies SARS-CoV-2 PCR vaccination public health health policy Figures Figure 1 Figure 2 Background People experiencing homelessness (PEH) may be at increased risk of SARS-CoV-2 infection and severe COVID-19 disease due to certain attributes of their lifestyle, which include lack of living accommodation, increased prevalence of chronic and physical conditions, and limited access to health care ( 1 ). Moreover, the lockdown measures used to control SARS-CoV-2 infections resulted in diminished access to services for PEH in many countries ( 2 ). Studies conducted during the first epidemic wave of SARS-CoV-2 infections in the US showed higher PCR positivity rates (i.e. current infection) among PEH than among the general population, with 16% testing positive in San Francisco ( 3 ) and 36% in Boston ( 4 ). These studies were however carried out in centers where COVID-19 outbreaks were taking place. A study in Marseille, France conducted during the same time period indicated a somewhat lower SARS-CoV-2 PCR positivity rate in a subsample of PEH, at 9% ( 5 ).The highest SARS-CoV-2 PCR positivity rate was found among PEH in homelessness facilities where overcrowding from sharing of dormitories and communal (e.g. shower) facilities was common ( 5 , 6 ). A study conducted across nine Dutch cities during the first wave reported a SARS-CoV-2 PCR positivity rate of 17% among PEH with COVID-related symptoms or who had a close contact with individuals with COVID-19 and visited the ‘street doctors’ ( 7 ), which was higher than the rate found among the general population during that period ( 8 ). In contrast, a population-based study from Wales, United Kingdom (UK) using routinely collected administrative data found that the SARS-CoV-2 PCR positivity rate among PEH was comparable to that of the general population (5.0% versus 5.6% between March 2020 and March 2021) ( 9 ). The authors suggest that this low percentage may have been due to the policy pandemic response for PEH, moving away from communal accommodation to offering PEH private rooms to reduce the risk of SARS-CoV-2 transmission( 9 ). In the Netherlands, no major outbreaks among visitors attending homelessness services had been identified since the start of the pandemic until December 2021, contrary to the situation in the US. It might be that the extra strategies set in place to control COVID-19 among PEH during the lockdown periods, such as those implemented in the UK( 9 ), resulted in limited transmission. Dutch municipalities provided emergency accommodations with more space for all PEH, irrespective of insurance and legal status, to be able to accommodate people who were unable to follow the “stay-home” measure ( 10 ). In addition, isolation and quarantine accommodations were offered to PEH who were infected with SARS-CoV-2 and to close contacts of infected individuals in homelessness services ( 10 ). However, infections in homelessness services may have stayed under the radar because PEH may be less likely to receive testing ( 11 ). As PCR testing of PEH may have occurred less frequently than among the general population, it is relevant to evaluate the prevalence of past SARS-CoV-2 infections in this group and among staff members working in the homelessness services who are frequently in close contact with PEH. Therefore, we conducted an on-site screening project at homelessness services in Amsterdam, aiming to assess the proportion of visitors and staff of homelessness services with positive SARS-CoV-2 PCR and antibody results, and sociodemographic, clinical and lifestyle determinants of current and past infection. In addition, we measured daily activities, compliance with preventive measures and intention to vaccinate against COVID-19 among visitors and staff members. Methods Study design We conducted a cross-sectional study among PEH, either living on the streets or residing in temporary shelters, and staff members working in homelessness services in Amsterdam, the Netherlands. We invited PEH and staff attending two locations for PEH in Amsterdam to participate in our study. One location included one homelessness service: a walk-in center (approximately 50 visitors per day). The other location included three homelessness services: a walk-in center (approximately 50 visitors per day), temporary housing (approximately 54 visitors per day) and emergency accommodation during lockdowns (approximately 54 visitors per day). Eligibility criteria Inclusion criteria were being a visitor/resident or staff member from the homelessness service, being 18 years or older, being proficient in Dutch, English or Polish and being able to understand the study information. Exclusion criteria were unable to hold an interview and/or provide informed consent or having severe COVID-19 related symptoms (including fever and shortness of breath), as perceived by the staff. At one testing location, staff members pre-selected visitors who had inclusion criteria. Study procedures Pre-study announcements (posters) were distributed a few weeks before the study. Between May 3 and May 21, 2021, we actively recruited visitors and staff members of the homelessness services, with the assistance of the coordinators of the centers. Visitors participated voluntarily and participants received a small gift plus 5 euros as incentive. Since major groups of PEH in Amsterdam are from Polish origin, a Polish translator was present during the study. Participants were able to opt-out for PCR testing, antibody testing or the questionnaire. Participants underwent a single throat plus nasopharyngeal swab for qPCR-testing inside a ‘testing bus’ (Supplementary Figure S.1). The qPCR targeted the E gene and the N genes with an internal control for correct swab sampling. It was validated at the Municipal public health laboratory of Amsterdam and performed using a modified protocol with the RotorGene platform (Qiagen, Hilden, Germany), as described previously (12). In addition, two drops of finger blood were collected via finger-stick for antibody testing using the COVID-19 IgG/IgM Rapid Test Cassette in a tent next to the bus (Biozek Medical, Apeldoorn, the Netherlands). After obtaining specimens for testing, individuals completed a short questionnaire with information about sociodemographics, lifestyle, (changes in) daily activities since the pandemic, COVID-19 testing, disease history, COVID-19 vaccination status, and comorbidities including lung problems, chronic heart disease, diabetes, severe kidney or liver disease, impaired resistance, infections with HIV, hepatitis B or hepatitis C or obesity. Compliance with COVID-19 prevention measures, including not shaking hands, wearing a face mask, washing hands and keeping 1.5 meters distance were measured on a 7 point Likert-scale, with responses ranging from 1 (‘never’) to 7 (‘always’). Vaccination intention was defined by two statements: (1) ‘Are you planning to get vaccinated against the coronavirus when it is your turn to be vaccinated?’ and (2) ‘What is the likelihood that you will actually be vaccinated against the coronavirus?’. Responses ranged from 1 (‘no, absolutely not’ and ‘very unlikely’) to 7 (‘yes, absolutely’ and ‘very likely’) on a 7-point Likert scale. Since the internal consistency of the statements demonstrated high reliability (Cronbach’s α=0.95), their responses were combined as a mean score. Vaccination intention was categorized into low (mean score 1.0-2.5), medium (3.0-5.0) and high (5.5-7.0), based on the distribution of the combined score (Supplementary Figure S.2). Trust in the governmental policy response to the pandemic was defined by the statement ‘How much do you trust the way the Dutch government is trying to keep the coronavirus under control’, with responses ranging from 1 (‘absolutely no trust’) to 5 (‘a great deal of trust’) on a 5-point Likert scale. This variable was categorized into low (score 1 or 2), neutral (score 3) and high (score 4 or 5). Statistical analyses Descriptive baseline characteristics were reported as means, median or percentages. We calculated the proportion of persons with a positive PCR-test result and the proportion with a positive antibody test result among those with a valid test result. 95% confidence intervals (CI)s were calculated using either the Clopper-Pearson or Jeffrey’s method, depending on whether the proportion was ≥0.02 or <0.02, respectively. Since a positive SARS-CoV-2 antibody test result may refer to either past infection or vaccination, we conducted sensitivity analyses for (i) visitors and (ii) staff members with a valid antibody result, presenting antibody results with exclusion of vaccinated persons and persons with an unknown vaccination status. Results Description of the study sample We included a total of 138 visitors and 53 staff members of the two locations with homelessness services for PEH in Amsterdam. Table 1 shows the demographics of our study population stratified by participant type. Visitors and staff members had a median age of 44 (IQR=37-51) and 40 (IQR=35-52) years, respectively. The majority of visitors and staff members were men (94% and 67%, respectively). Most visitors were from Eastern/Central European origin (46%), and most staff members (62%) were from Dutch origin. Additional information on sleep locations and lifestyle characteristics of the visitors can be found in Supplementary Table S1. The majority of visitors resided in a temporary homeless shelter (36.3%), emergency accommodation (28.9%) or the streets (17.8%). Regular use of cannabis was reported by 40.9%, and regular use of hard drugs was reported by 11.4% of visitors. Daily or weekly use of alcohol was reported by 46.3% of visitors. Table 1 Sociodemographic and lifestyle characteristics of visitors and staff members of homeless shelters in Amsterdam, the Netherlands, May 2021. Visitors (n=138) n (%) Staff members (n=53) n (%) Total sample (n=191) 2 n (%) Sociodemographic and lifestyle characteristics Age in years , median [IQR] 44.0 [37.0-51.0] 40.0 [35.0-52.0] 43.0 [36.0-51.0] Sex Female Male 8 (6.0) 126 (94.0) 17 (32.7) 35 (67.3) 25 (13.4) 161 (86.6) Region of birth The Netherlands Africa Eastern/Central Europe Southwest Asia South America, Caribbean/Antilles Other 1 11 (8.2) 29 (21.6) 62 (46.3) 9 (6.7) 15 (11.2) 8 (6.0) 33 (62.3) 7 (13.2) 6 (11.3) 2 (3.8) 3 (5.7) 2 (3.8) 44 (23.5) 36 (19.3) 68 (36.4) 11 (5.9) 18 (9.6) 10 (5.3) Gone to work in past 7 days Never 106 (78.5) 3 (5.7) 109 (58.0) Sometimes (1-6 times) 27 (20.0) 45 (84.9) 72 (38.3) Daily (7 times) 2 (1.5) 5 (9.4) 7 (3.7) Injecting drug use No 108 (81.8) N.A. N.A. Yes, former 17 (12.9) N.A. N.A. Yes, recent (past month) 7 (5.3) N.A. N.A. Abbreviations: IQR interquartile range; N.A.= not asked. 1 Other = Western Europe (not the Netherlands), USA and Australia 2 N-values may vary due to missing variables (visitors: n=4 for age, n=4 for sex, n=4 for region of birth, n=3 for gone to work, n=6 for injecting drug use; staff: n=1 for sex) Table 2 SARS-CoV-2 PCR and antibody test results and vaccination status among visitors and staff members of homeless shelters in Amsterdam, the Netherlands, May 2021. Visitors (n=138) n (%, 95%CI) Staff members (n=53) n (%, 95%CI) Total sample (n=191) n (%, 95%CI) SARS-CoV-2 PCR Positive test 0 (0, 0-1.9) 1 (3.1, 0.1-16.2) 1 (0.6, 0.1-2.8) Declined testing 1 5 21 26 SARS-CoV-2 antibodies Positive test 4 (3.0, 0.8-7.5) 6 (11.3, 4.3-23.0) 10 (5.3, 2.6-9.6) Positive test, without being vaccinated 2 2 (1.6, 0.3-5.0) 5 (10.9, 3.6-23.6) 7 (4.0, 1.6-8.2) Declined testing/invalid result 1 4 0 4 COVID-19 vaccination status 3 No 128 (94.8) 41 (85.4) 169 (92.3) Partly 1 (0.7) 4 (8.3) 5 (2.7) Fully 2 (1.5) 3 (6.3) 5 (2.7) Partially but unknown vaccine 4 (3.0) 0 (0) 4 (2.2) Unknown 3 5 8 Abbreviations: SARS-CoV-2 Severe Acute Respiratory Syndrome Coronavirus; PCR Polymerase chain reaction; CI confidence interval. 1 From the total study sample, 5 visitors and 21 staff members declined participation in PCR testing, resulting in a total of n=133 for visitors and n=32 for staff. A total of 3 visitors declined participation in antibody testing, and one visitor had an invalid test result, resulting in a total of n=134 for visitors and n=53 for staff. 2 Fourteen participants were vaccinated against SARS-CoV-2 (3 visitors and 7 staff members) or had an unknown vaccination status (4 visitors) and were therefore excluded in this analyses. 3 The variable vaccination status has 8 missings (3 for clients, 5 for staff). Participants were partially vaccinated when they received 1 dose of Pfizer, Moderna or AstraZeneca, and fully vaccinated when they received 2 doses of Pfizer, Moderna or AstraZeneca, or 1 dose of Janssen. The vaccination status ‘partly but unknown vaccine’ refers to if participants had one dose of an unknown vaccine. Prevalence of SARS-CoV-2 infection and antibodies Among visitors, the prevalence of SARS-CoV-2 infection was 0% (0/133, 95%CI=0-1.9) and the prevalence of SARS-CoV-2 antibody positivity was 3% (4/134, 95%CI=0.8-7.5) for the total sample and 1.6% (2/131, 95%=0.3-5.0) when excluding vaccinated visitors (Table 2). Among staff members, the prevalence of SARS-CoV-2 infection was 3% (1/32, 95%CI=0.1-16.2) and the prevalence of SARS-CoV-2 antibody positivity was 11.3% (6/53, 95%CI=4.3-23) and 10.9% (5/46, 95%CI=3.6-23.6) when excluding vaccinated staff (Table 2). Analysis examining the determinants of current and past SARS-CoV-2 infections was precluded by the small number of infections in our study population. Clinical symptoms related to COVID-19 A large proportion of visitors and staff (44.1% and 41.5% of the total sample, respectively) reported at least one COVID-related clinical symptom during the survey, such as a nasal cold or a cough, irrespective of infection (Figure 1). The one SARS-CoV-2 PCR-positive individual reported no respiratory or other COVID-related symptoms. Five out of seven (71.4%) SARS-CoV-2 antibody positive individuals reported at least one clinical symptom, and this percentage was similar among antibody negative individuals (67.6% reported at least one symptom). Twenty eight percent of visitors and 9% of staff members reported at least one comorbid condition, mainly chronic lung problems. Potential exposure to COVID-19: daily activities and previous testing Overall, visitors seem to report fewer daytime activities and contact patterns, such as going to work or visiting friends, than staff (Supplementary Table S2). Thirty three percent (33%) of visitors reported to have lost their paid work and 37% of visitors spent more time at the shelter than before the COVID-19 pandemic (Supplementary Table S3). Among visitors, 41% (55/134) reported previous testing for SARS-CoV-2 infection and 5.9% (8/135) a previous infection not confirmed with a test (self-report). Of those, 1 visitor also tested antibody positive in our study. Among staff members, 30% (16/53) reported previous testing, 40% (21/53) a previous infection not confirmed with a test, and 15% (8/53) a previous infection confirmed with a test (self-report). Of those, 4 staff members tested antibody positive in our study. Compliance with preventive measures The majority of visitors and staff were frequently or regularly compliant with the basic COVID preventive measures ‘not shaking hands’, ‘wearing a face mask’ and ‘washing hands’ (Figure 2A and 2B). Not all visitors and staff were compliant with the measure of ‘keeping 1.5 meters distance’: 23.9% and 13.2%, respectively, reported never or seldom keeping 1.5 meters distance to other people (i.e., frequent close contacts) in the past 7 days. Intention to vaccinate and (mis)trust in governmental COVID-19 policy Intention to vaccinate against COVID-19 was lower among visitors than among staff members: 57.8% of visitors and 45.0% of staff scored ‘low’ or ‘medium’ (Figure 2C and 2D), the remaining participants scored ‘high’ (42.2 of visitors and 55% of staff). In addition, trust in the governmental policy response to the COVID-19 pandemic was reported as ‘no or limited trust’ for 27% of visitors and for 17% of staff members (Figure 2E and 2F). 41.0% of visitors and 30.2% of staff members had ‘some or a lot of trust’ in the governmental policy response, the remaining participants (32.1% of visitors and 52.8% of staff) scored ‘neutral’ (Figure 2E and 2F). Discussion This cross-sectional study reports on the proportion of visitors and staff of homelessness services who were SARS-CoV-2 PCR and antibody positive in Amsterdam during May 2021, at the end of the second wave of infection in the Netherlands. The proportion of participants with current and past SARS-CoV-2 infection was low (0% and 1.6%, respectively) among visitors, and somewhat higher among staff members (3% and 10.9%). These findings are in contrast to earlier studies from the Netherlands (7), France (5) and the US (3, 4) conducted during the first wave, showing high PCR positivity rates for SARS-CoV-2 infection among PEH. Notably, these studies either included PEH suspected of COVID-19 (7) or recruited PEH at shelters where a COVID-19 cluster was identified (3, 4) or during the peak of infections (5), all of which likely resulted in higher PCR positivity estimates than during a non-peak period. This was shown in later studies at shelters in the US where no or only one previous PCR positive case was identified (13), resulting in a substantially lower SARS-CoV-2 PCR positivity rate among PEH: 5% in Seattle, Washington (14); 4% in Atlanta, Georgia (13), 2% in King-County, Washington (14). Our results are in line with a population level study from Wales, UK showing lower PCR positivity among PEH as compared to the general population (9). The authors explain this finding by a proactive policy response directing local authorities on sourcing additional temporary accommodation for PEH, including, for instance, hotels and bed and breakfasts accommodation and adapted night-shelters, a situation comparable to the Netherlands. Amsterdam had less densely homelessness services during the pandemic (e.g., limited numbers of PEH) and different shelter policies (e.g., sufficient resources to prevent overcrowding) than other cities outside of the Netherlands. Earlier research in the UK suggests that single-room accommodation and heightened infection prevention methods are important strategies to prevent COVID-19 disease in homeless populations (15). Moreover, since the Dutch community of PEH is relatively small, estimated at around 32,000 in 2021(16) and 5000 in Amsterdam(17), access to homeless communities is relatively easy in the Netherlands, contrary to the inability to reach PEH as reported in other countries such as the US (18). Amsterdam has a wide range of homelessness services available on a walk-in basis (also during the day) for all PEH independent of legal status, including both EU and non-EU citizens, to prevent rough sleeping and improve access to health care for PEH. There is also an ongoing collaboration of homelessness services with the local Public Health Services, which may have contributed to implementing preventive strategies in the shelters. Another explanation for the low percentage of participants with current SARS-CoV-2 infections is the drop in SARS-CoV-2 incidence in Amsterdam during our study period, which took place at the end of the second lockdown and which had significant impact on reducing individual activities and travel behavior (19). Other explanations for the low SARS-CoV-2 (sero)prevalence among PEH could be the limited contact patterns of PEH, relativity good compliance with preventive measures, the increased spacing between beds and reduced client-to-client contact during the lockdowns and decreased daytime activities at homelessness services. Our overall antibody seroprevalence (including asymptotic past infection) estimate was 1.6% among PEH and 11% among staff (who were not vaccinated), as compared to 12% in the general population in the Netherlands (20). In a prospective cohort study in Amsterdam, the cumulative incidence of SARS-COV-2 among residents ranged from 15.9% for Dutch-born individuals to 64.6% for Ghanaian-born individuals at the end of March 2021 (21). The proportion of past infection (i.e. SARS-CoV-2 2 antibodies) in our study was also substantially lower than found in other countries such as France(22, 23). A cross-sectional study conducted during the lockdown of the first wave in Paris, SARS-CoV-2 seroprevalence ranged from 28% to 89% among 818 PEH and was highest among PEH who lived in densely populated worker residences (22). Another community-based study in June 2020 among 1,156 PEH in Marseille, France showed antibody positivity ranging from 2.2% in people who lived on the streets to 8.1% in people living in emergency shelters (23), which is more in line with our findings. Considering the mixed results from these studies, SARS-CoV-2 (sero-)prevalence needs to be evaluated with at a country-specific level and monitored at different timepoints among PEH. The low proportion of past SARS-CoV-2 infections for PEH is notable, although this could also be explained by the same reasons as described regarding results from the PCR prevalence, that is, less exposure to the virus due to a solitary life and the situation in the homelessness services in Amsterdam, i.e. the governmental and personal preventive measures. The proportion of past SARS-CoV-2 infections based on self-report was substantially higher than based on antibody testing. This difference could be due to recall or reporting bias of participants. On the other hand, we may have underestimated the proportion of participants with a past infection since later studies showed that the point-of-care (POC) test that we used in our study had relatively low sensitivity for individuals with mild or asymptomatic infections, estimated at 85.7% (95CI=65.4-95.0) (24). In addition, the waning of antibodies post-infection occurs over time and POC tests have shorter detectability windows than other serologic laboratory assays (25), limiting comparison of our result for antibodies with the Dutch general population. Future studies should incorporate more accurate testing than point-of-care testing to study the proportion of past SARS-CoV-2 infections in a community setting. Our study further showed that COVID-19 related symptoms were frequently reported among both PEH and staff members in our study, irrespective of being infected with SARS-CoV-2. This is in line with earlier findings that COVID-19 related symptoms among PEH are a weak predictor of current SARS-CoV-2 infection (4) and that many PEH can have SARS-CoV-2 infections without reporting symptoms (5). Hence, screening aymptomatic individuals during periods with peaks in COVID-19 cases could be considered, particularly in places where overcrowding cannot be avoided. The low or medium vaccination intention and the mistrust in the government’s SARS-CoV-2 policy response warrants further attention, particularly because this study took place before the Dutch government offered vaccination to visitors of homelessness services. This may have led to a lower vaccination uptake among PEH but no data are currently available to evaluate uptake in this group. Hence, examining whether this population is sufficiently protected for COVID-19 severe disease and mortality by infection is warranted, particularly as new variants of concern continue to circulate. Our study has several limitations. First, testing represents a single time point at the end of the second wave of infections including a relatively small sample of PEH and staff members attending two sites for PEH in Amsterdam. A study among a larger group of PEH during a different time period of restrictions may result in different estimates. Second, the acceptance rate of our study is unclear because participants were recruited with the assistance of coordinators of the centers who did not register the number of individuals invited to participate and the reasons for non-participation. In conclusion, this was the first study estimating current and past SARS-CoV-2 infections among PEH and staff of homelessness services in the Netherlands. A major facilitating factor for this screening study was the good accessibility of homeless communities in the Netherlands. Our study suggests that the additional preventive policy measures in homelessness services in Amsterdam may have resulted in limited COVID transmission among PEH, although the effect of having less contacts and a more solitary life than the general population could not be ruled out. Therefore, as COVID-19 continues to circulate around the world, emergency services for PEH should remain in place and vaccination uptake should be evaluated, in particular because PEH are regarded to be at increased risk of severe COVID-19 due to comorbidities (7, 26), including infections such as hepatitis C (27), and because we found vaccination intention among PEH to be low. abbreviations CI Confidence interval IgG Immunoglobuline G IgM Immunoglobine M IQR Interquartile range N.A. Not asked PEH People experiencing homelessness PCR Polymerase chain reaction qPCR Quantitative polymerase chain reaction SARS-CoV-2 Severe Acute Respiratory Syndrome Coronavirus UK United Kingdom Declarations Ethics approval and consent to participate All participants provided written informed consent. The project was conducted according to the ethical guidelines of the 1975 Declaration of Helsinki. The local medical ethics committee of Amsterdam UMC, location AMC approved the research project (NL76623.018.21). Consent for publication Not applicable. Availability of data and materials The datasets generated and/or analysed during the current study are not publicly available due to national privacy policies but are available from the corresponding author on reasonable request. For data related requests, please contact Dr Ellen Generaal, E: [email protected] . Competing interests None to declare by the corresponding author. Funding This study was funded by the Public Health Service of Amsterdam. Authors' contributions Conceptualization, E.G., D.K.v.S., M.P.; methodology, D.K.v.S. and A.B.; formal analysis, S.C., E.G.; resources, E.G., M.B., D.P.; data curation, S.C.; writing—original draft preparation, E.G.; supervision, D.K.v.S. and M.P.; project administration, E.G. and M.B.; funding acquisition, E.G. and M.v.D.L. All authors have read and agreed to the published version of the manuscript. Acknowledgements The authors would like to acknowledge all participants and employees of the homelessness service of De Regenboog Groep, Leger des Heils and HVO Querido for their close collaboration. References Ralli M, Arcangeli A, Ercoli L. Homelessness and COVID-19: Leaving No One Behind. Ann Glob Health. 2021;87(1):11. The Organisation for Economic Co-operation and Development. The terriorial impact of COVID-19: managing the crisis across levels of government.; 2020. 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Environment. NIfPHat. RIVM 'inschalingstabel' , internal report (May 10, 2021). 2021. Thomas I, Mackie P. A population level study of SARS-CoV-2 prevalence amongst people experiencing homelessness in Wales, UK. Int J Popul Data Sci. 2020;5(4):1695. RIVM policy guidelines for accomodation of people experiencing homelessness, april 2021 (In Dutch: Richtlijn opvang dak- en thuisloze mensen). [Available from: https://www.rijksoverheid.nl/documenten/richtlijnen/2020/11/05/richtlijn-opvang-dak--en-thuisloze-mensen. Accessed August 5, 2022. Knight KR, Duke MR, Carey CA, Pruss G, Garcia CM, Lightfoot M, et al. COVID-19 Testing and Vaccine Acceptability Among Homeless-Experienced Adults: Qualitative Data from Two Samples. J Gen Intern Med. 2022;37(4):823-9. Corman VM, Landt O, Kaiser M, Molenkamp R, Meijer A, Chu DK, et al. Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR. Euro Surveill. 2020;25(3). Mosites E, Parker EM, Clarke KEN, Gaeta JM, Baggett TP, Imbert E, et al. Assessment of SARS-CoV-2 Infection Prevalence in Homeless Shelters - Four U.S. Cities, March 27-April 15, 2020. MMWR Morb Mortal Wkly Rep. 2020;69(17):521-2. Rogers JH, Link AC, McCulloch D, Brandstetter E, Newman KL, Jackson ML, et al. Characteristics of COVID-19 in Homeless Shelters : A Community-Based Surveillance Study. Ann Intern Med. 2021;174(1):42-9. Lewer D, Braithwaite I, Bullock M, Eyre MT, White PJ, Aldridge RW, et al. COVID-19 among people experiencing homelessness in England: a modelling study. Lancet Respir Med. 2020;8(12):1181-91. Central Bureau of Statistics N. [Available from: https://www.cbs.nl/nl-nl/cijfers/detail/84990NED. Accessed August 5, 2022. Personal communication M. Buster and Dylan Price PHSoA. Rodriguez NM, Lahey AM, MacNeill JJ, Martinez RG, Teo NE, Ruiz Y. Homelessness during COVID-19: challenges, responses, and lessons learned from homeless service providers in Tippecanoe County, Indiana. BMC Public Health. 2021;21(1):1657. de Haas M, Faber R, Hamersma M. How COVID-19 and the Dutch 'intelligent lockdown' change activities, work and travel behaviour: Evidence from longitudinal data in the Netherlands. Transp Res Interdiscip Perspect. 2020;6:100150. RIVM. PIENTER Corona Onderzoek. [Available from: https://www.rivm.nl/pienter-corona-onderzoek/resultaten#rm-wetenschappelijke-artikelen-592431-more. Accessed August 5, 2022. Coyer L, Boyd A, Schinkel J, Agyemang C, Galenkamp H, Koopman ADM, et al. Differences in SARS-CoV-2 infections during the first and second wave of SARS-CoV-2 between six ethnic groups in Amsterdam, the Netherlands: A population-based longitudinal serological study. Lancet Reg Health Eur. 2022;13:100284. Thomas Roederer, Bastien Mollo, Charline Vincent, Birgit Nikolay, Augusto Llosa, Robin Nesbitt, et al. High seroprevalence of SARS-CoV-2 antibodies among people living in precarious situations in Ile de France. . PrePrint. Loubiere S, Monfardini E, Allaria C, Mosnier M, Allibert A, Ninove L, et al. Seroprevalence of SARS-CoV-2 antibodies among homeless people living rough, in shelters and squats: A large population-based study in France. PLoS One. 2021;16(9):e0255498. van den Beld MJC, Murk JL, Kluytmans J, Koopmans MPG, Reimerink J, van Loo IHM, et al. Increasing the Efficiency of a National Laboratory Response to COVID-19: a Nationwide Multicenter Evaluation of 47 Commercial SARS-CoV-2 Immunoassays by 41 Laboratories. J Clin Microbiol. 2021;59(9):e0076721. Alfego D, Sullivan A, Poirier B, Williams J, Adcock D, Letovsky S. A population-based analysis of the longevity of SARS-CoV-2 antibody seropositivity in the United States. EClinicalMedicine. 2021;36:100902. Schrooyen L, Delforge M, Lebout F, Vanbaelen T, Lecompte A, Dauby N. Homeless people hospitalized with COVID-19 in Brussels. Clin Microbiol Infect. 2021;27(1):151-2. Kondili LA, Craxì L, Andreoni M, Mennini FS, Razavi H. Opportunistic co-screening for HCV and COVID-19-related services: A creative response with a need for thoughtful reflection. Liver Int. 2022;42(5):960-2. Additional Declarations No competing interests reported. Supplementary Files SupplementaryTablesCOMOV11cor.docx Cite Share Download PDF Status: Posted 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-1949434","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":131909703,"identity":"17948983-93a8-4d18-a48b-77575b5b04a0","order_by":0,"name":"Ellen Generaal","email":"data:image/png;base64,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","orcid":"","institution":"Public Health Service of Amsterdam","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Ellen","middleName":"","lastName":"Generaal","suffix":""},{"id":131909704,"identity":"3413988d-036e-4e89-9cda-b8b0208812dc","order_by":1,"name":"Daniela van Santen","email":"","orcid":"","institution":"Public Health Service of 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Amsterdam","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Mariken","middleName":"van der","lastName":"Lubben","suffix":""},{"id":131909714,"identity":"8d796bc6-23bd-4283-b099-3cd3ff1ea9ac","order_by":11,"name":"Yvonne van Duijnhoven","email":"","orcid":"","institution":"Public Health Service of Rotterdam","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yvonne","middleName":"van","lastName":"Duijnhoven","suffix":""},{"id":131909715,"identity":"7023cd0e-81c2-4565-8e72-4db8d4a7b741","order_by":12,"name":"Maria Prins","email":"","orcid":"","institution":"Public Health Service of Amsterdam","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Maria","middleName":"","lastName":"Prins","suffix":""}],"badges":[],"createdAt":"2022-08-10 13:59:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1949434/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1949434/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":25851857,"identity":"06e85c49-181f-484b-b9c2-d0a64e421d75","added_by":"auto","created_at":"2022-08-30 16:31:16","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":22448,"visible":true,"origin":"","legend":"\u003cp\u003eSelf-reported COVID-19 related symptoms* among visitors and staff members of homeless \u003c/p\u003e\u003cp\u003e services over the past 7 days in Amsterdam, the Netherlands, May 2021.\u003c/p\u003e\u003cp\u003e * Missing variables for symptoms: n=2 for visitors, 0 for staff.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-1949434/v1/0425cefbf720b934bf704705.png"},{"id":25851419,"identity":"d35aba7b-ba93-431b-ae90-ea089a32e43f","added_by":"auto","created_at":"2022-08-30 16:26:16","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":55558,"visible":true,"origin":"","legend":"\u003cp\u003e(A) Compliance with the basic COVID-19 prevention measures (in the past 7 days) for visitors (n=4 missing variables) \u003c/p\u003e\u003cp\u003e(B) Compliance with the basic COVID-19 prevention measures (in the past 7 days) for staff. \u003c/p\u003e\u003cp\u003e(C) SARS-CoV-2 vaccination intention for visitors (n=4 missing variables). \u003c/p\u003e\u003cp\u003e(D) SARS-CoV-2 vaccination intention for staff (n=1 missing variable). \u003c/p\u003e\u003cp\u003e(E) Trust in the Dutch governmental COVID-19 policy response for visitors. \u003c/p\u003e\u003cp\u003e(F) Trust in the Dutch governmental COVID-19 policy response for staff.\u0026nbsp;\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-1949434/v1/d96d4d63cee271c6f4de8579.png"},{"id":29897158,"identity":"9b0eaa4d-cf73-4e06-a432-db3571a8e03f","added_by":"auto","created_at":"2022-12-05 12:29:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":520481,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1949434/v1/ed4a4d6b-c6c7-4e9c-957c-619b7d712842.pdf"},{"id":25851421,"identity":"4398e378-bcff-4e6b-b53a-36c933a61dbb","added_by":"auto","created_at":"2022-08-30 16:26:16","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":505137,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryTablesCOMOV11cor.docx","url":"https://assets-eu.researchsquare.com/files/rs-1949434/v1/774fd3a98f91df4a2af56316.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Low prevalence of current and past SARS-CoV-2 infections among visitors and staff members of homelessness services in Amsterdam at the end of the second wave of infections in the Netherlands","fulltext":[{"header":"Background","content":"\u003cp\u003ePeople experiencing homelessness (PEH) may be at increased risk of SARS-CoV-2 infection and severe COVID-19 disease due to certain attributes of their lifestyle, which include lack of living accommodation, increased prevalence of chronic and physical conditions, and limited access to health care (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Moreover, the lockdown measures used to control SARS-CoV-2 infections resulted in diminished access to services for PEH in many countries (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eStudies conducted during the first epidemic wave of SARS-CoV-2 infections in the US showed higher PCR positivity rates (i.e. current infection) among PEH than among the general population, with 16% testing positive in San Francisco (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) and 36% in Boston (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e). These studies were however carried out in centers where COVID-19 outbreaks were taking place. A study in Marseille, France conducted during the same time period indicated a somewhat lower SARS-CoV-2 PCR positivity rate in a subsample of PEH, at 9% (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e).The highest SARS-CoV-2 PCR positivity rate was found among PEH in homelessness facilities where overcrowding from sharing of dormitories and communal (e.g. shower) facilities was common (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e). A study conducted across nine Dutch cities during the first wave reported a SARS-CoV-2 PCR positivity rate of 17% among PEH with COVID-related symptoms or who had a close contact with individuals with COVID-19 and visited the \u0026lsquo;street doctors\u0026rsquo; (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e), which was higher than the rate found among the general population during that period (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e). In contrast, a population-based study from Wales, United Kingdom (UK) using routinely collected administrative data found that the SARS-CoV-2 PCR positivity rate among PEH was comparable to that of the general population (5.0% versus 5.6% between March 2020 and March 2021) (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). The authors suggest that this low percentage may have been due to the policy pandemic response for PEH, moving away from communal accommodation to offering PEH private rooms to reduce the risk of SARS-CoV-2 transmission(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn the Netherlands, no major outbreaks among visitors attending homelessness services had been identified since the start of the pandemic until December 2021, contrary to the situation in the US. It might be that the extra strategies set in place to control COVID-19 among PEH during the lockdown periods, such as those implemented in the UK(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e), resulted in limited transmission. Dutch municipalities provided emergency accommodations with more space for all PEH, irrespective of insurance and legal status, to be able to accommodate people who were unable to follow the \u0026ldquo;stay-home\u0026rdquo; measure (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). In addition, isolation and quarantine accommodations were offered to PEH who were infected with SARS-CoV-2 and to close contacts of infected individuals in homelessness services (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e). However, infections in homelessness services may have stayed under the radar because PEH may be less likely to receive testing (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e). As PCR testing of PEH may have occurred less frequently than among the general population, it is relevant to evaluate the prevalence of past SARS-CoV-2 infections in this group and among staff members working in the homelessness services who are frequently in close contact with PEH.\u003c/p\u003e \u003cp\u003eTherefore, we conducted an on-site screening project at homelessness services in Amsterdam, aiming to assess the proportion of visitors and staff of homelessness services with positive SARS-CoV-2 PCR and antibody results, and sociodemographic, clinical and lifestyle determinants of current and past infection. In addition, we measured daily activities, compliance with preventive measures and intention to vaccinate against COVID-19 among visitors and staff members.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eStudy design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe conducted a cross-sectional study among PEH, either living on the streets or residing in temporary shelters, and staff members working in homelessness services in Amsterdam, the Netherlands. We invited PEH and staff attending two locations for PEH in Amsterdam to participate in our study. One location included one homelessness service: a walk-in center (approximately 50 visitors per day). The other location included three homelessness services: a walk-in center (approximately 50 visitors per day), temporary housing (approximately 54 visitors per day) and emergency accommodation during lockdowns (approximately 54 visitors per day).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEligibility criteria\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInclusion criteria were being a visitor/resident or staff member from the homelessness service, being 18 years or older, being proficient in Dutch, English or Polish and being able to understand the study information. Exclusion criteria were unable to hold an interview and/or provide informed consent or having severe COVID-19 related symptoms (including fever and shortness of breath), as perceived by the staff. At one testing location, staff members pre-selected visitors who had inclusion criteria. \u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy procedures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePre-study announcements (posters) were distributed a few weeks before the study. Between\u0026nbsp;May 3 and May 21, 2021,\u0026nbsp;we actively recruited visitors and staff members of the homelessness services, with the assistance of the coordinators of the centers. Visitors participated voluntarily and\u0026nbsp;participants received a small gift plus 5 euros as incentive. Since major groups of PEH in Amsterdam are from Polish origin, a Polish translator was present during the study. Participants were able to opt-out for PCR testing, antibody testing or the questionnaire.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eParticipants underwent a single throat plus\u0026nbsp;nasopharyngeal\u0026nbsp;swab for qPCR-testing inside a \u0026lsquo;testing bus\u0026rsquo; (Supplementary Figure S.1). The qPCR targeted the E gene and the N genes with an internal control for correct swab sampling. It was validated at the Municipal public health laboratory of Amsterdam and performed using a modified protocol with the RotorGene platform (Qiagen, Hilden, Germany), as described previously\u0026nbsp;(12). In addition, two drops of finger blood were collected via finger-stick for antibody testing\u0026nbsp;using the COVID-19 IgG/IgM Rapid Test Cassette in a tent next to the bus (Biozek Medical, Apeldoorn, the Netherlands).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAfter obtaining specimens for testing, individuals completed a short questionnaire with information about sociodemographics, lifestyle, (changes in) daily activities since the pandemic, COVID-19 testing, disease history, COVID-19 vaccination status, and comorbidities including lung problems, chronic heart disease, diabetes, severe kidney or liver disease, impaired resistance, infections with HIV, hepatitis B or hepatitis C or obesity. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCompliance with COVID-19 prevention measures, including not shaking hands, wearing a face mask, washing hands and keeping 1.5 meters distance were measured on a 7 point Likert-scale, with responses ranging from 1 (\u0026lsquo;never\u0026rsquo;) to 7 (\u0026lsquo;always\u0026rsquo;). Vaccination intention was defined by two statements: (1) \u0026lsquo;Are you planning to get vaccinated against the coronavirus when it is your turn to be vaccinated?\u0026rsquo; and (2) \u0026lsquo;What is the likelihood that you will actually be vaccinated against the coronavirus?\u0026rsquo;. Responses ranged from 1 (\u0026lsquo;no, absolutely not\u0026rsquo; and \u0026lsquo;very unlikely\u0026rsquo;) to 7 (\u0026lsquo;yes, absolutely\u0026rsquo; and \u0026lsquo;very likely\u0026rsquo;) on a 7-point Likert scale. Since the internal consistency of the statements demonstrated high reliability (Cronbach\u0026rsquo;s \u0026alpha;=0.95), their responses were combined as a mean score. Vaccination intention was categorized into low (mean score 1.0-2.5), medium (3.0-5.0) and high (5.5-7.0), based on the distribution of the combined score (Supplementary Figure S.2). Trust in the governmental policy response to the pandemic was defined by the statement \u0026lsquo;How much do you trust the way the Dutch government is trying to keep the coronavirus under control\u0026rsquo;, with responses ranging from 1 (\u0026lsquo;absolutely no trust\u0026rsquo;) to 5 (\u0026lsquo;a great deal of trust\u0026rsquo;) on a 5-point Likert scale. This variable was categorized into low (score 1 or 2), neutral (score 3) and high (score 4 or 5).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analyses\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDescriptive baseline characteristics were reported as means, median or percentages. We calculated the proportion of persons with a positive PCR-test result and the proportion with a positive antibody test result among those with a valid test result. 95% confidence intervals (CI)s were calculated using either the Clopper-Pearson or Jeffrey\u0026rsquo;s method, depending on whether the proportion was \u0026ge;0.02 or \u0026lt;0.02, respectively. Since a positive SARS-CoV-2 antibody test result may refer to either past infection or vaccination, we conducted sensitivity analyses for (i) visitors and (ii) staff members with a valid antibody result, presenting antibody results with exclusion of vaccinated persons and persons with an unknown vaccination status.\u0026nbsp;\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eDescription of the study sample\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe included a total of 138 visitors and 53 staff members of the two locations with homelessness services for PEH in Amsterdam. Table 1 shows the demographics of our study population stratified by participant type. Visitors and staff members had a median age of 44 (IQR=37-51) and 40 (IQR=35-52) years, respectively. The majority of visitors and staff members were men (94% and 67%, respectively). Most visitors were from Eastern/Central European origin (46%), and most staff members (62%) were from Dutch origin. Additional information on sleep locations and lifestyle characteristics of the visitors can be found in Supplementary Table S1. The majority of visitors resided in a temporary homeless shelter (36.3%), emergency accommodation (28.9%) or the streets (17.8%). Regular use of cannabis was reported by 40.9%, and regular use of hard drugs was reported by 11.4% of visitors. Daily or weekly use of alcohol was reported by 46.3% of visitors.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e\u003c/p\u003e\n\u003cp style=\"text-align: center;\"\u003e\u0026nbsp;Sociodemographic and lifestyle characteristics of visitors and staff members of homeless shelters in Amsterdam, the Netherlands, May 2021.\u003c/p\u003e\n\u003ctable align=\"\" border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e\u003cstrong\u003eVisitors (n=138)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003en (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003e\u003cstrong\u003eStaff members (n=53)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003en (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal sample\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n=191)\u0026nbsp;\u003c/strong\u003e\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003en (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eSociodemographic and lifestyle characteristics\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge in years\u003c/strong\u003e, median [IQR]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e44.0 [37.0-51.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003e40.0 [35.0-52.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003e43.0 [36.0-51.0]\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u003cstrong\u003eSex\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; Female\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; Male\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e8 (6.0)\u003c/p\u003e\n \u003cp\u003e126 (94.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e17 (32.7)\u003c/p\u003e\n \u003cp\u003e35 (67.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e25 (13.4)\u003c/p\u003e\n \u003cp\u003e161 (86.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u003cstrong\u003eRegion of birth\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; The Netherlands\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;Africa\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;Eastern/Central Europe\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;Southwest Asia\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;South America, Caribbean/Antilles \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp; Other \u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e11 (8.2)\u003c/p\u003e\n \u003cp\u003e29 (21.6)\u003c/p\u003e\n \u003cp\u003e62 (46.3)\u003c/p\u003e\n \u003cp\u003e9 (6.7)\u003c/p\u003e\n \u003cp\u003e15 (11.2)\u003c/p\u003e\n \u003cp\u003e8 (6.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e33 (62.3)\u003c/p\u003e\n \u003cp\u003e7 (13.2)\u003c/p\u003e\n \u003cp\u003e6 (11.3)\u003c/p\u003e\n \u003cp\u003e2 (3.8)\u003c/p\u003e\n \u003cp\u003e3 (5.7)\u003c/p\u003e\n \u003cp\u003e2 (3.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e44 (23.5)\u003c/p\u003e\n \u003cp\u003e36 (19.3)\u003c/p\u003e\n \u003cp\u003e68 (36.4)\u003c/p\u003e\n \u003cp\u003e11 (5.9)\u003c/p\u003e\n \u003cp\u003e18 (9.6)\u003c/p\u003e\n \u003cp\u003e10 (5.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" width=\"100%\"\u003e\n \u003cp\u003e\u003cstrong\u003eGone to work in past 7 days\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; Never\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e106 (78.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003e3 (5.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003e109 (58.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; Sometimes (1-6 times)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e27 (20.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003e45 (84.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003e72 (38.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; Daily (7 times)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e2 (1.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003e5 (9.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003e7 (3.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u003cstrong\u003eInjecting drug use\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;No\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e108 (81.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003eN.A.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003eN.A.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;Yes, former\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e17 (12.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003eN.A.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003eN.A.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"37.881219903691814%\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp;Yes, recent (past month)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"21.187800963081862%\"\u003e\n \u003cp\u003e7 (5.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"18.13804173354735%\"\u003e\n \u003cp\u003eN.A.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"22.792937399678973%\"\u003e\n \u003cp\u003eN.A.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eAbbreviations:\u0026nbsp;\u003cem\u003eIQR\u0026nbsp;\u003c/em\u003einterquartile range; N.A.= not asked.\u0026nbsp;\u003cbr\u003e\u003csup\u003e1\u003c/sup\u003e Other = Western Europe (not the Netherlands), USA and Australia\u0026nbsp;\u003cbr\u003e\u003csup\u003e2\u0026nbsp;\u003c/sup\u003eN-values may vary due to missing variables (visitors: n=4 for age, n=4 for sex, n=4 for region of birth, n=3 for gone to work, n=6 for injecting drug use; staff: n=1 for sex)\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e\u003c/p\u003e\n\u003cp style=\"text-align: center;\"\u003e\u0026nbsp;SARS-CoV-2 PCR and antibody test results and vaccination status among visitors and staff members of homeless shelters in Amsterdam, the Netherlands, May 2021.\u003c/p\u003e\n\u003ctable align=\"\" border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e\u003cstrong\u003eVisitors (n=138)\u0026nbsp;\u003cbr\u003e\u0026nbsp;\u003c/strong\u003en (%, 95%CI) \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e\u003cstrong\u003eStaff members (n=53)\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003en (%, 95%CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e\u003cstrong\u003eTotal sample (n=191)\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003en (%, 95%CI)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eSARS-CoV-2 PCR\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003ePositive test\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e0 (0, 0-1.9) \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e1 (3.1, 0.1-16.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e1 (0.6, 0.1-2.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003eDeclined testing \u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eSARS-CoV-2 antibodies\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003ePositive test\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e4 (3.0, 0.8-7.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e6 (11.3, 4.3-23.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e10 (5.3, 2.6-9.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003ePositive test, without being vaccinated\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e2 (1.6, 0.3-5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e5 (10.9, 3.6-23.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e7 (4.0, 1.6-8.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003eDeclined testing/invalid result \u003csup\u003e1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003e\u003cstrong\u003eCOVID-19 vaccination status \u003csup\u003e3\u003c/sup\u003e\u003c/strong\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e128 (94.8)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e41 (85.4)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e169 (92.3) \u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003ePartly \u0026nbsp; \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e1 (0.7)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e4 (8.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e5 (2.7)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003eFully\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e2 (1.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e3 (6.3)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e5 (2.7)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003ePartially but unknown vaccine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e4 (3.0)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e0 (0)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e4 (2.2)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"31.86490455212922%\"\u003e\n \u003cp\u003eUnknown\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"20.851688693098385%\"\u003e\n \u003cp\u003e3\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e5\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.641703377386197%\"\u003e\n \u003cp\u003e8\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eAbbreviations: \u003cem\u003eSARS-CoV-2\u003c/em\u003e Severe Acute Respiratory Syndrome Coronavirus; \u003cem\u003ePCR\u003c/em\u003e Polymerase chain reaction; \u003cem\u003eCI\u0026nbsp;\u003c/em\u003econfidence interval.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e1\u003c/sup\u003e From the total study sample, 5 visitors and 21 staff members declined participation in PCR testing, resulting in a total of n=133 for visitors and n=32 for staff. A total of 3 visitors declined participation in antibody testing, and one visitor had an invalid test result, resulting in a total of n=134 for visitors and n=53 for staff.\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e2\u0026nbsp;\u003c/sup\u003eFourteen participants were vaccinated against SARS-CoV-2 (3 visitors and 7 staff members) \u0026nbsp;or had an unknown vaccination status (4 visitors) and were therefore excluded in this analyses.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003csup\u003e3\u0026nbsp;\u003c/sup\u003eThe variable vaccination status has 8 missings (3 for clients, 5 for staff). \u0026nbsp;Participants were partially vaccinated when they received 1 dose of Pfizer, Moderna or AstraZeneca, and fully vaccinated when they received 2 doses of Pfizer, Moderna or AstraZeneca, or 1 dose of Janssen. The vaccination status \u0026lsquo;partly but unknown vaccine\u0026rsquo; refers to if participants had one dose of an unknown vaccine. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePrevalence of SARS-CoV-2 infection and antibodies\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmong visitors, the prevalence of SARS-CoV-2 infection was 0% (0/133, 95%CI=0-1.9) and the prevalence of SARS-CoV-2 antibody positivity was 3% (4/134, 95%CI=0.8-7.5) for the total sample and 1.6% (2/131, 95%=0.3-5.0) when excluding vaccinated visitors (Table 2). Among staff members, the prevalence of SARS-CoV-2 infection was 3% (1/32, 95%CI=0.1-16.2) and the prevalence of SARS-CoV-2 antibody positivity was 11.3% (6/53, 95%CI=4.3-23) and 10.9% (5/46, 95%CI=3.6-23.6) when excluding vaccinated staff (Table 2). Analysis examining the determinants of current and past SARS-CoV-2 infections was precluded by the small number of infections in our study population.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical symptoms related to COVID-19\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA large proportion of visitors and staff (44.1% and 41.5% of the total sample, respectively) reported at least one COVID-related clinical symptom during the survey, such as a nasal cold or a cough, irrespective of infection (Figure 1). The one SARS-CoV-2 PCR-positive individual reported no respiratory or other COVID-related symptoms. Five out of seven (71.4%) SARS-CoV-2 antibody positive individuals reported at least one clinical symptom, and this percentage was similar among antibody negative individuals (67.6% reported at least one symptom). Twenty eight percent of visitors and 9% of staff members reported at least one comorbid condition, mainly chronic lung problems.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePotential exposure to COVID-19: daily activities and previous testing\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOverall, visitors seem to report fewer daytime activities and contact patterns, such as going to work or visiting friends, than staff (Supplementary Table S2). Thirty three percent (33%) of visitors reported to have lost their paid work and 37% of visitors spent more time at the shelter than before the COVID-19 pandemic (Supplementary Table S3). Among visitors, 41% (55/134) reported previous testing for SARS-CoV-2 infection and 5.9% (8/135) a previous infection not confirmed with a test (self-report). Of those, 1 visitor also tested antibody positive in our study. Among staff members, 30% (16/53) reported previous testing, 40% (21/53) a previous infection not confirmed with a test, and 15% (8/53) a previous infection confirmed with a test (self-report). Of those, 4 staff members tested antibody positive in our study. \u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompliance with preventive measures\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe majority of visitors and staff were frequently or regularly compliant with the basic COVID preventive measures \u0026lsquo;not shaking hands\u0026rsquo;, \u0026lsquo;wearing a face mask\u0026rsquo; and \u0026lsquo;washing hands\u0026rsquo; (Figure 2A and 2B). Not all visitors and staff were compliant with the measure of \u0026lsquo;keeping 1.5 meters distance\u0026rsquo;: 23.9% and 13.2%, respectively, reported never or seldom keeping 1.5 meters distance to other people (i.e., frequent close contacts) in the past 7 days.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIntention to vaccinate and (mis)trust in governmental COVID-19 policy\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIntention to vaccinate against COVID-19 was lower among visitors than among staff members: 57.8% of visitors and 45.0% of staff scored \u0026lsquo;low\u0026rsquo; or \u0026lsquo;medium\u0026rsquo; (Figure 2C and 2D), the remaining participants scored \u0026lsquo;high\u0026rsquo; (42.2 of visitors and 55% of staff). In addition, trust in the governmental policy response to the COVID-19 pandemic was reported as \u0026lsquo;no or limited trust\u0026rsquo; for 27% of visitors and for 17% of staff members (Figure 2E and 2F). 41.0% of visitors and 30.2% of staff members had \u0026lsquo;some or a lot of trust\u0026rsquo; in the governmental policy response, the remaining participants (32.1% of visitors and 52.8% of staff) scored \u0026lsquo;neutral\u0026rsquo; (Figure 2E and 2F).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis cross-sectional study reports on the proportion of visitors and staff of homelessness services who were SARS-CoV-2 PCR and antibody positive in Amsterdam during May 2021, at the end of the second wave of infection in the Netherlands. The proportion of participants with current and past SARS-CoV-2 infection was low (0% and 1.6%, respectively) among visitors, and somewhat higher among staff members (3% and 10.9%). These findings are in contrast to earlier studies from the Netherlands (7), France (5) and the US (3, 4) conducted during the first wave, showing high PCR positivity rates for SARS-CoV-2 infection among PEH. Notably, these studies either included PEH suspected of COVID-19 (7) or recruited PEH at shelters where a COVID-19 cluster was identified (3, 4) or during the peak of infections (5), all of which likely resulted in higher PCR positivity estimates than during a non-peak period. This was shown in later studies at shelters in the US where no or only one previous PCR positive case was identified (13), resulting in a substantially lower SARS-CoV-2 PCR positivity rate among PEH: 5% in Seattle, Washington (14); 4% in Atlanta, Georgia (13), 2% in King-County, Washington (14). \u003c/p\u003e\n\u003cp\u003eOur results are in line with a population level study from Wales, UK showing lower PCR positivity among PEH as compared to the general population (9). The authors explain this finding by a proactive policy response directing local authorities on sourcing additional temporary accommodation for PEH, including, for instance, hotels and bed and breakfasts accommodation and adapted night-shelters, a situation comparable to the Netherlands. Amsterdam had less densely homelessness services during the pandemic (e.g., limited numbers of PEH) and different shelter policies (e.g., sufficient resources to prevent overcrowding) than other cities outside of the Netherlands. Earlier research in the UK suggests that single-room accommodation and heightened infection prevention methods are important strategies to prevent COVID-19 disease in homeless populations (15). Moreover, since the Dutch community of PEH is relatively small, estimated at around 32,000 in 2021(16) and 5000 in Amsterdam(17), access to homeless communities is relatively easy in the Netherlands, contrary to the inability to reach PEH as reported in other countries such as the US (18). Amsterdam has a wide range of homelessness services available on a walk-in basis (also during the day) for all PEH independent of legal status, including both EU and non-EU citizens, to prevent rough sleeping and improve access to health care for PEH. There is also an ongoing collaboration of homelessness services with the local Public Health Services, which may have contributed to implementing preventive strategies in the shelters. \u003c/p\u003e\n\u003cp\u003eAnother explanation for the low percentage of participants with current SARS-CoV-2 infections is the drop in SARS-CoV-2 incidence in Amsterdam during our study period, which took place at the end of the second lockdown and which had significant impact on reducing individual activities and travel behavior (19). Other explanations for the low SARS-CoV-2 (sero)prevalence among PEH could be the limited contact patterns of PEH, relativity good compliance with preventive measures, the increased spacing between beds and reduced client-to-client contact during the lockdowns and decreased daytime activities at homelessness services.\u003c/p\u003e\n\u003cp\u003eOur overall antibody seroprevalence (including asymptotic past infection) estimate was 1.6% among PEH and 11% among staff (who were not vaccinated), as compared to 12% in the general population in the Netherlands (20). In a prospective cohort study in Amsterdam, the cumulative incidence of SARS-COV-2 among residents ranged from 15.9% for Dutch-born individuals to 64.6% for Ghanaian-born individuals at the end of March 2021 (21). The proportion of past infection (i.e. SARS-CoV-2 2 antibodies) in our study was also substantially lower than found in other countries such as France(22, 23). A cross-sectional study conducted during the lockdown of the first wave in Paris, SARS-CoV-2 seroprevalence ranged from 28% to 89% among 818 PEH and was highest among PEH who lived in densely populated worker residences (22). Another community-based study in June 2020 among 1,156 PEH in Marseille, France showed antibody positivity ranging from 2.2% in people who lived on the streets to 8.1% in people living in emergency shelters (23), which is more in line with our findings. Considering the mixed results from these studies, SARS-CoV-2 (sero-)prevalence needs to be evaluated with at a country-specific level and monitored at different timepoints among PEH.\u003c/p\u003e\n\u003cp\u003eThe low proportion of past SARS-CoV-2 infections for PEH is notable, although this could also be explained by the same reasons as described regarding results from the PCR prevalence, that is, less exposure to the virus due to a solitary life and the situation in the homelessness services in Amsterdam, i.e. the governmental and personal preventive measures. The proportion of past SARS-CoV-2 infections based on self-report was substantially higher than based on antibody testing. This difference could be due to recall or reporting bias of participants. On the other hand, we may have underestimated the proportion of participants with a past infection since later studies showed that the point-of-care (POC) test that we used in our study had relatively low sensitivity for individuals with mild or asymptomatic infections, estimated at 85.7% (95CI=65.4-95.0) (24). In addition, the waning of antibodies post-infection occurs over time and POC tests have shorter detectability windows than other serologic laboratory assays (25), limiting comparison of our result for antibodies with the Dutch general population. Future studies should incorporate more accurate testing than point-of-care testing to study the proportion of past SARS-CoV-2 infections in a community setting.\u003c/p\u003e\n\u003cp\u003eOur study further showed that COVID-19 related symptoms were frequently reported among both PEH and staff members in our study, irrespective of being infected with SARS-CoV-2. This is in line with earlier findings that COVID-19 related symptoms among PEH are a weak predictor of current SARS-CoV-2 infection (4) and that many PEH can have SARS-CoV-2 infections without reporting symptoms (5). Hence, screening aymptomatic individuals during periods with peaks in COVID-19 cases could be considered, particularly in places where overcrowding cannot be avoided.\u003c/p\u003e\n\u003cp\u003eThe low or medium vaccination intention and the mistrust in the government\u0026rsquo;s SARS-CoV-2 policy response warrants further attention, particularly because this study took place before the Dutch government offered vaccination to visitors of homelessness services. This may have led to a lower vaccination uptake among PEH but no data are currently available to evaluate uptake in this group. Hence, examining whether this population is sufficiently protected for COVID-19 severe disease and mortality by infection is warranted, particularly as new variants of concern continue to circulate. \u003c/p\u003e\n\u003cp\u003eOur study has several limitations. First, testing represents a single time point at the end of the second wave of infections including a relatively small sample of PEH and staff members attending two sites for PEH in Amsterdam. A study among a larger group of PEH during a different time period of restrictions may result in different estimates. Second, the acceptance rate of our study is unclear because participants were recruited with the assistance of coordinators of the centers who did not register the number of individuals invited to participate and the reasons for non-participation. \u003c/p\u003e\n\u003cp\u003eIn conclusion, this was the first study estimating current and past SARS-CoV-2 infections among PEH and staff of homelessness services in the Netherlands. A major facilitating factor for this screening study was the good accessibility of homeless communities in the Netherlands. Our study suggests that the additional preventive policy measures in homelessness services in Amsterdam may have resulted in limited COVID transmission among PEH, although the effect of having less contacts and a more solitary life than the general population could not be ruled out. Therefore, as COVID-19 continues to circulate around the world, emergency services for PEH should remain in place and vaccination uptake should be evaluated, in particular because PEH are regarded to be at increased risk of severe COVID-19 due to comorbidities (7, 26), including infections such as hepatitis C (27), and because we found vaccination intention among PEH to be low.\u003c/p\u003e"},{"header":"abbreviations","content":"\u003cp\u003eCI Confidence interval\u003c/p\u003e\n\u003cp\u003eIgG Immunoglobuline G\u003c/p\u003e\n\u003cp\u003eIgM Immunoglobine M\u003c/p\u003e\n\u003cp\u003eIQR Interquartile range\u003c/p\u003e\n\u003cp\u003eN.A. Not asked\u003c/p\u003e\n\u003cp\u003ePEH People experiencing homelessness\u003c/p\u003e\n\u003cp\u003ePCR Polymerase chain reaction\u003c/p\u003e\n\u003cp\u003eqPCR Quantitative polymerase chain reaction\u003c/p\u003e\n\u003cp\u003eSARS-CoV-2 Severe Acute Respiratory Syndrome Coronavirus\u003c/p\u003e\n\u003cp\u003eUK United Kingdom\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cul\u003e\n \u003cli style=\"font-weight: bold;\"\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eAll participants provided written informed consent. The project was conducted according to the ethical guidelines of the 1975 Declaration of Helsinki.\u0026nbsp;The local medical ethics committee of Amsterdam UMC, location AMC approved the research project (NL76623.018.21).\u003c/p\u003e\n\u003cul\u003e\n \u003cli style=\"font-weight: bold;\"\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cul\u003e\n \u003cli style=\"font-weight: bold;\"\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThe datasets generated and/or analysed during the current study are not publicly available due to national privacy policies but are available from the corresponding author on reasonable request. For data related requests, please contact Dr Ellen Generaal, E: [email protected].\u003c/p\u003e\n\u003cul\u003e\n \u003cli style=\"font-weight: bold;\"\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eNone to declare by the corresponding author.\u003c/p\u003e\n\u003cul\u003e\n \u003cli style=\"font-weight: bold;\"\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eThis study was funded by the Public Health Service of Amsterdam.\u003c/p\u003e\n\u003cul\u003e\n \u003cli style=\"font-weight: bold;\"\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003eConceptualization, E.G., D.K.v.S., M.P.; methodology, D.K.v.S. and A.B.; formal analysis, S.C., E.G.; resources, E.G., M.B., D.P.; data curation, S.C.; writing\u0026mdash;original draft preparation, E.G.; supervision, D.K.v.S. and M.P.; project administration, E.G. and M.B.; funding acquisition, E.G. and M.v.D.L. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cul\u003e\n \u003cli style=\"font-weight: bold;\"\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e\n\u003cp\u003e\u0026nbsp;The authors would like to acknowledge all participants and employees of the homelessness service of De Regenboog Groep, Leger des Heils and HVO Querido for their close collaboration.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eRalli M, Arcangeli A, Ercoli L. Homelessness and COVID-19: Leaving No One Behind. Ann Glob Health. 2021;87(1):11.\u003c/li\u003e\n\u003cli\u003eThe Organisation for Economic Co-operation and Development. The terriorial impact of COVID-19: managing the crisis across levels of government.; 2020.\u003c/li\u003e\n\u003cli\u003eImbert E, Kinley PM, Scarborough A, Cawley C, Sankaran M, Cox SN, et al. Coronavirus Disease 2019 Outbreak in a San Francisco Homeless Shelter. Clin Infect Dis. 2021;73(2):324-7.\u003c/li\u003e\n\u003cli\u003eBaggett TP, Keyes H, Sporn N, Gaeta JM. Prevalence of SARS-CoV-2 Infection in Residents of a Large Homeless Shelter in Boston. JAMA. 2020;323(21):2191-2.\u003c/li\u003e\n\u003cli\u003eLy TDA, Nguyen NN, Hoang VT, Goumballa N, Louni M, Canard N, et al. Screening of SARS-CoV-2 among homeless people, asylum-seekers and other people living in precarious conditions in Marseille, France, March-April 2020. Int J Infect Dis. 2021;105:1-6.\u003c/li\u003e\n\u003cli\u003eTobolowsky FA, Gonzales E, Self JL, Rao CY, Keating R, Marx GE, et al. COVID-19 Outbreak Among Three Affiliated Homeless Service Sites - King County, Washington, 2020. MMWR Morb Mortal Wkly Rep. 2020;69(17):523-6.\u003c/li\u003e\n\u003cli\u003eIgor van Laere, Tessa van Loenen, Eline Mennis, Michelle Hobus, Maria Kloosterman, Maartje Arts, et al. COVID-19 en dakloosheid in Nederland. RadboudUMC and Nederlandse Straatdokters Groep; 2020.\u003c/li\u003e\n\u003cli\u003eEnvironment. NIfPHat. RIVM \u0026apos;inschalingstabel\u0026apos; , internal report (May 10, 2021). 2021.\u003c/li\u003e\n\u003cli\u003eThomas I, Mackie P. A population level study of SARS-CoV-2 prevalence amongst people experiencing homelessness in Wales, UK. Int J Popul Data Sci. 2020;5(4):1695.\u003c/li\u003e\n\u003cli\u003eRIVM policy guidelines for accomodation of people experiencing homelessness, april 2021 (In Dutch: Richtlijn opvang dak- en thuisloze mensen). [Available from: https://www.rijksoverheid.nl/documenten/richtlijnen/2020/11/05/richtlijn-opvang-dak--en-thuisloze-mensen. Accessed August 5, 2022.\u003c/li\u003e\n\u003cli\u003eKnight KR, Duke MR, Carey CA, Pruss G, Garcia CM, Lightfoot M, et al. COVID-19 Testing and Vaccine Acceptability Among Homeless-Experienced Adults: Qualitative Data from Two Samples. J Gen Intern Med. 2022;37(4):823-9.\u003c/li\u003e\n\u003cli\u003eCorman VM, Landt O, Kaiser M, Molenkamp R, Meijer A, Chu DK, et al. Detection of 2019 novel coronavirus (2019-nCoV) by real-time RT-PCR. Euro Surveill. 2020;25(3).\u003c/li\u003e\n\u003cli\u003eMosites E, Parker EM, Clarke KEN, Gaeta JM, Baggett TP, Imbert E, et al. Assessment of SARS-CoV-2 Infection Prevalence in Homeless Shelters - Four U.S. Cities, March 27-April 15, 2020. MMWR Morb Mortal Wkly Rep. 2020;69(17):521-2.\u003c/li\u003e\n\u003cli\u003eRogers JH, Link AC, McCulloch D, Brandstetter E, Newman KL, Jackson ML, et al. Characteristics of COVID-19 in Homeless Shelters : A Community-Based Surveillance Study. Ann Intern Med. 2021;174(1):42-9.\u003c/li\u003e\n\u003cli\u003eLewer D, Braithwaite I, Bullock M, Eyre MT, White PJ, Aldridge RW, et al. COVID-19 among people experiencing homelessness in England: a modelling study. Lancet Respir Med. 2020;8(12):1181-91.\u003c/li\u003e\n\u003cli\u003eCentral Bureau of Statistics N. [Available from: https://www.cbs.nl/nl-nl/cijfers/detail/84990NED. Accessed August 5, 2022.\u003c/li\u003e\n\u003cli\u003ePersonal communication M. Buster and Dylan Price PHSoA.\u003c/li\u003e\n\u003cli\u003eRodriguez NM, Lahey AM, MacNeill JJ, Martinez RG, Teo NE, Ruiz Y. Homelessness during COVID-19: challenges, responses, and lessons learned from homeless service providers in Tippecanoe County, Indiana. BMC Public Health. 2021;21(1):1657.\u003c/li\u003e\n\u003cli\u003ede Haas M, Faber R, Hamersma M. How COVID-19 and the Dutch \u0026apos;intelligent lockdown\u0026apos; change activities, work and travel behaviour: Evidence from longitudinal data in the Netherlands. Transp Res Interdiscip Perspect. 2020;6:100150.\u003c/li\u003e\n\u003cli\u003eRIVM. PIENTER Corona Onderzoek. [Available from: https://www.rivm.nl/pienter-corona-onderzoek/resultaten#rm-wetenschappelijke-artikelen-592431-more. Accessed August 5, 2022.\u003c/li\u003e\n\u003cli\u003eCoyer L, Boyd A, Schinkel J, Agyemang C, Galenkamp H, Koopman ADM, et al. Differences in SARS-CoV-2 infections during the first and second wave of SARS-CoV-2 between six ethnic groups in Amsterdam, the Netherlands: A population-based longitudinal serological study. Lancet Reg Health Eur. 2022;13:100284.\u003c/li\u003e\n\u003cli\u003eThomas Roederer, Bastien Mollo, Charline Vincent, Birgit Nikolay, Augusto Llosa, Robin Nesbitt, et al. High seroprevalence of SARS-CoV-2 antibodies among people living in precarious situations in Ile de France. . PrePrint.\u003c/li\u003e\n\u003cli\u003eLoubiere S, Monfardini E, Allaria C, Mosnier M, Allibert A, Ninove L, et al. Seroprevalence of SARS-CoV-2 antibodies among homeless people living rough, in shelters and squats: A large population-based study in France. PLoS One. 2021;16(9):e0255498.\u003c/li\u003e\n\u003cli\u003evan den Beld MJC, Murk JL, Kluytmans J, Koopmans MPG, Reimerink J, van Loo IHM, et al. Increasing the Efficiency of a National Laboratory Response to COVID-19: a Nationwide Multicenter Evaluation of 47 Commercial SARS-CoV-2 Immunoassays by 41 Laboratories. J Clin Microbiol. 2021;59(9):e0076721.\u003c/li\u003e\n\u003cli\u003eAlfego D, Sullivan A, Poirier B, Williams J, Adcock D, Letovsky S. A population-based analysis of the longevity of SARS-CoV-2 antibody seropositivity in the United States. EClinicalMedicine. 2021;36:100902.\u003c/li\u003e\n\u003cli\u003eSchrooyen L, Delforge M, Lebout F, Vanbaelen T, Lecompte A, Dauby N. Homeless people hospitalized with COVID-19 in Brussels. Clin Microbiol Infect. 2021;27(1):151-2.\u003c/li\u003e\n\u003cli\u003eKondili LA, Crax\u0026igrave; L, Andreoni M, Mennini FS, Razavi H. Opportunistic co-screening for HCV and COVID-19-related services: A creative response with a need for thoughtful reflection. Liver Int. 2022;42(5):960-2.\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"homeless persons, shelters, COVID-19, SARS-CoV-2, COVID-19 testing, SARS-CoV-2 antibodies, SARS-CoV-2 PCR, vaccination, public health, health policy","lastPublishedDoi":"10.21203/rs.3.rs-1949434/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1949434/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e People experiencing homelessness (PEH) may be at increased risk of SARS-CoV-2 infection and severe COVID-19. The Dutch government established emergency shelters and introduced preventive measures for homelessness services and there were no major SARS-CoV-2 outbreak noticed among PEH during the first two waves of infections. This study aimed to assess the prevalence of current and past infections among PEH and staff at the end of the second COVID-19 wave by conducting an on-site COVID-19 screening project at homelessness services in Amsterdam, the Netherlands. \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e We assessed the proportion of visitors and staff members of four homelessness services at two locations in Amsterdam with positive SARS-CoV-2 qPCR and antibody results (IgG/IgM Rapid Test, Biozek) in May 2021. We also assessed sociodemographic, clinical and lifestyle characteristics, compliance with basic prevention measures and intention to vaccinate against COVID-19 among PEH and staff.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e A total of 138 visitors and 53 staff members filled out a questionnaire and were tested. Among PEH, the SARS-CoV-2 positivity rate was 0% (0/133;95%CI=0-1.9) and the antibody positivity rate was 1.6% (2/131;95%CI=0.8-7.5). Among staff, these percentages were 3% (1/32;95%CI=0.1-16.2) and 11% (5/53;95%CI=3.6-23.6), respectively. Most participants were frequently compliant with the basic preventive measures ‘not shaking hands’, ‘wearing a face mask’ and ‘washing hands’, but not with ‘physical distancing’. Overall, intention to vaccinate for COVID-19 was low (30% for visitors, 10% for staff) or medium (28% for visitors, 35% for staff). Trust in COVID-19 policies were also, for the most part, low (27% for visitors, 17% for staff) or neutral (32% for visitors, 53% for staff).\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e We observed a low prevalence of past and current SARS-CoV-2 infections among PEH, which may be explained by instated shelter policies, limited daily activities of PEH and compliance with certain prevention measures. Vaccine hesitancy and mistrust among visitors and staff could hinder vaccination uptake, suggesting that improvements in public heath communication and interventions towards visitors and staff of homelessness services are needed.\u003c/p\u003e","manuscriptTitle":"Low prevalence of current and past SARS-CoV-2 infections among visitors and staff members of homelessness services in Amsterdam at the end of the second wave of infections in the Netherlands","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-08-30 16:26:14","doi":"10.21203/rs.3.rs-1949434/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"08933b3d-e042-4a37-823d-a13b95fff941","owner":[],"postedDate":"August 30th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-12-05T12:29:25+00:00","versionOfRecord":[],"versionCreatedAt":"2022-08-30 16:26:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1949434","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1949434","identity":"rs-1949434","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}