Very high relative seroprevalence of anti-SARS-CoV-2 antibodies among communities in Bangui, Central African Republic

BackgroundLarge-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. ObjectiveThe objective of our survey was to estimate the cumulative population immunity for COVID-19 and to identify individual characteristics associated with a positive serostatus. MethodThis 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. ResultsAll up, 799 participants were surveyed. The average age was 27 years, and 45{middle dot}8% of the respondents were male (sex ratio: 0.8). The overall proportion of respondents with a positive serostatus was 74{middle dot}1%. Participants over 20 years of age were twice as likely to have a positive serostatus, with an OR of 2.{middle dot} {middle dot}2 (95% CI: [1{middle dot}6, 3{middle dot}1]). InterpretationThe 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, particularly on its variants burden, remain to be determined. FundingThis 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.