Background: Large-scale population-based seroprevalence studies of SARS-CoV-2 are essential to characterize the cumulative incidence of SARS-CoV-2 infection and to extrapolate the prevalence of presumptive immunity at the population level.Objective: The objective of our survey was to estimate the cumulative population immunity for COVID-19 and to identify individual characteristics associated with a positive serostatus.Method: This was a clustered cross-sectional study conducted from July 12 to August 20, 2021, in households in the city of Bangui, the capital of the Central African Republic. Information regarding demographic characteristics (age, gender, and place of residence), comorbidities (chronic diseases) was collected. A venous blood sample was obtained for each participant to determine the level of total anti-SARS-CoV-2 antibodies using a WANTAI SARS-CoV-2 Ab ELISA kit.Results: All up, 799 participants were surveyed. The average age was 27 years, and 45·8% of the respondents were male (sex ratio: 0.8). The overall proportion of respondents with a positive serostatus was 74·1%. Participants over 20 years of age were twice as likely to have a positive serostatus, with an OR of 2.· ·2 (95% CI: [1·6, 3·1]).Interpretation: The results of this survey revealed a high cumulative level of immunity in Bangui, thus indicating a significant degree of spread of SARS-CoV-2 in the population. The public health implications of this high level of immunity to SARS-CoV-2 in the population remain to be determined.Funding Information: This study was funded by the French Ministry for Europe and Foreign Affairs through the REPAIR COVID-19-Africa project coordinated by the Pasteur International Network association.Declaration of Interests: All authors declare no competing interests.Ethics Approval Statement: This study was authorised by the Ministry of Health of the Central African Republic (N° 603/MSPP/DIRCAB/CMRF-21) and by the Ethics and Scientific Committee of the University of Bangui (N°09/UB/FACSS/IPB/CES/20). Informed and signed consent was obtained from each participant.
Very High Relative Seroprevalence of Anti--SARS-CoV-2 Antibodies Among Communities in Bangui, Central African Republic (preprint)