TY - JOUR T1 - SARS-CoV-2 antibody prevalence in Sierra Leone, March 2021: a cross-sectional, nationally representative, age-stratified serosurvey JF - BMJ Global Health JO - BMJ Global Health DO - 10.1136/bmjgh-2021-007271 VL - 6 IS - 11 SP - e007271 AU - Mohamed Bailor Barrie AU - Sulaiman Lakoh AU - J Daniel Kelly AU - Joseph Sam Kanu AU - James Sylvester Squire AU - Zikan Koroma AU - Silleh Bah AU - Osman Sankoh AU - Abdulai Brima AU - Rashid Ansumana AU - Sarah A Goldberg AU - Smit Chitre AU - Chidinma Osuagwu AU - Raphael Frankfurter AU - Justin Maeda AU - Bernard Barekye AU - Tamuno-Wari Numbere AU - Mohammed Abdulaziz AU - Anthony Mounts AU - Curtis Blanton AU - Tushar Singh AU - Mohamed Samai AU - Mohamed Vandi AU - Eugene T Richardson Y1 - 2021/11/01 UR - http://gh.bmj.com/content/6/11/e007271.abstract N2 - Introduction As of 26 March 2021, the Africa Centres for Disease Control and Prevention had reported 4 159 055 cases of COVID-19 and 111 357 deaths among the 55 African Union member states; however, no country has published a nationally representative serosurvey as of October 2021. Such data are vital for understanding the pandemic’s progression on the continent, evaluating containment measures, and policy planning.Methods We conducted a cross-sectional, nationally representative, age-stratified serosurvey in Sierra Leone in March 2021 by randomly selecting 120 Enumeration Areas throughout the country and 10 randomly selected households in each of these. One to two persons per selected household were interviewed to collect information on sociodemographics, symptoms suggestive of COVID-19, exposure history to laboratory-confirmed COVID-19 cases, and history of COVID-19 illness. Capillary blood was collected by fingerstick, and blood samples were tested using the Hangzhou Biotest Biotech RightSign COVID-19 IgG/IgM Rapid Test Cassette. Total seroprevalence was estimated after applying sampling weights.Results The overall weighted seroprevalence was 2.6% (95% CI 1.9% to 3.4%). This was 43 times higher than the reported number of cases. Rural seropositivity was 1.8% (95% CI 1.0% to 2.5%), and urban seropositivity was 4.2% (95% CI 2.6% to 5.7%).Discussion Overall seroprevalence was low compared with countries in Europe and the Americas (suggesting relatively successful containment in Sierra Leone). This has ramifications for the country’s third wave (which started in June 2021), during which the average number of daily reported cases was 87 by the end of the month:this could potentially be on the order of 3700 actual infections per day, calling for stronger containment measures in a country with only 0.2% of people fully vaccinated. It may also reflect significant under-reporting of incidence and mortality across the continent.Data are available upon reasonable request. ER -