SARS-CoV-2 immunoepidemiology in Wellcome-funded urban and rural cohorts in Malawi : generating evidence to inform regional medium and long term decision making

General population serosurveillance in low-income Africa is fundamental to understanding the population exposure to SARS-CoV-2, to explain the observed epidemiology and to ensure that ongoing control measures in the region are proportionate and are not guided by observations from very different settings. Detailed longitudinal immunological studies of infected individuals will be key to determining the long-term strategy in managing COVID-19 in highly vulnerable African populations. Utilising the longitudinal urban and rural cohorts established by the Malawi Epidemiology and Intervention Research Unit, and supported by international and national expertise, we will undertake population immunoepidemiological surveillance to understand the trends in exposure and transmission of SARS-CoV-2, risk factors for SARS-CoV-2 infection and severe disease, as well as the proportion of asymptomatic or pauci-symptomatic infection in the population to enable an accurate estimate of infection fatality rate. Furthermore, we will recruit individuals with evidence of past SARS-CoV-2 infection to a nested cohort with 3-monthly sampling, to explore the magnitude and duration of antibody response and protective immunity in the Malawian population, and at the same time creating a biorepository for further in-depth virological and immunological studies.