SARS-CoV-2 prevalence and immunity: a hospital-based study from Malawi

• DOI: 10.1016/j.ijid.2021.12.336
• Publication Date: 2021-12-17T12:00:31Z
• Authors: C. Meinus; R. Singer; B. Nandi; O. Jagot; B. Becker-Ziaja; B. Karo; B. Mvula; A. Jansen; J. Baumann; A. Schultz
• Keywords: 360; ddc:610; Malawi; serosurvey; SARS-CoV-2; prevalence; 610; COVID-19; Infectious and parasitic diseases; RC109-216; immunity; Article; Hospitals; 3. Good health; 03 medical and health sciences; Cross-Sectional Studies; 0302 clinical medicine; Africa; Prevalence; Humans; ddc:610; 610 Medizin und Gesundheit

COVID-19 transmission and disease dynamics in sub-Saharan Africa are not well understood. Our study aims to provide insight into COVID-19 epidemiology in Malawi by estimating SARS-CoV-2 prevalence and immunity after SARS-CoV-2 infection in a hospital-based setting.We conducted a hospital-based, convenience sampling, cross-sectional survey for SARS-CoV-2 in Lilongwe, Malawi. Participants answered a questionnaire and were tested for SARS-CoV-2 by enzyme-linked immunosorbent assay and real-time reverse-transcription polymerase chain reaction (RT-PCR). A surrogate virus neutralization test (sVNT) was performed in seropositive samples to estimate immunity. Poisson regression was used to assess SARS-CoV-2 point prevalence association with demographic and behavioral variables.The study included 930 participants. We found a combined point prevalence of 10.1%. Separately analyzed, RT-PCR positivity was 2.0%, and seropositivity was 9.3%. Of tested seropositive samples, 90.1% were sVNT positive. We found a high rate (45.7%) of asymptomatic SARS-CoV-2 infection. SARS-CoV-2 point prevalence was significantly associated with being a healthcare worker.Our study suggests that official data underestimate COVID-19 transmission. Using sVNTs to estimate immunity in Malawi is feasible and revealed considerable post-infection immunity in our cohort. Subclinical infection and transmission are probably a game-changer in surveillance, mitigation and vaccination strategies.