Seroprevalence and risk factors for SARS-CoV-2 Infection in selected urban areas in Ethiopia: a cross-sectional evaluation during July 2020

Tadesse, Enyew Birru; Endris, Abduilhafiz A; Solomon, Henok; Alayu, Mikias; Kebede, Adisu; Eshetu, Kirubel; Teka, Gizaw; Seid, Biniyam Eskinder; Ahmed, Jelaludin; Abayneh, Sisay Alemayehu; Gerawork, Beyene Mogesc Hizikiyas; Sugerman, David; Assefa, Zewdu; Abayneh, Aschalew; Abate, Ebba; Taddese, Lia

BACKGROUND: : Ethiopia reported the first case of COVID-19 on March 13(th), 2020 with community transmission ensue by mid-May. National, population-based serosurvey against anti-SARS-CoV-2 IgG was conducted to measure the prevalence of prior COVID-19 infections and better approximate the burden across major towns in Ethiopia. METHODS: : We conducted a cross-sectional, population-based serosurvey from June 24 to July 8, 2020 in 14 major urban areas. Two-stage cluster sampling was used to randomly select enumeration areas and households. All persons aged ≥15 years were enrolled. Serum samples tested by Abbott™ ARCHITECT™ assay for SARS-CoV-2 IgG antibodies. National COVID-19 surveillance data on the median date of the serosurvey is analyzed for comparison. FINDINGS: : Adjusted seroprevalence was 3.5% (95% CI: 3.2%-3.8%) after controlling for age, sex and test kit performance. Males (3.7%) and females (3.3%) were nearly equally infected, while middle-aged adults 40-65 years had the highest (4.0%) prevalence. Gambella (7.5%), Dire Dawa (6.2%) and Jigjiga (6.1%) were most affected towns. About 6.7% and 8.0% of seropositives had symptoms and chronic underlying illness, respectively. Surveillance system had identified 4,416 RT-PCR confirmed cases in Addis Ababa. INTERPRETATION: : This serosurvey shows majority of urban Ethiopians remain uninfected with SARS-CoV-2. Most anti-SARS-CoV-2 IgG positive cases were asymptomatic with no underlying illness, keeping case detection to a minimum.