What is the prevalence of COVID-19 detection by PCR among deceased individuals in Lusaka, Zambia? A postmortem surveillance study

Abstract

Objectives To determine the prevalence of COVID-19 postmortem setting in Lusaka, Zambia. Design A systematic, postmortem prevalence study. Setting A busy, inner-city morgue in Lusaka. Participants We sampled a random subset of all decedents who transited the University Teaching Hospital morgue. We sampled the posterior nasopharynx of decedents using quantitative PCR. Prevalence was weighted to account for age-specific enrolment strategies. Interventions Not applicable - this was an observational study. Primary outcomes Prevalence of COVID-19 detections by PCR. Results were stratified by setting (facility vs community deaths), age, demographics and geography and time. Secondary outcomes Shifts in viral variants; causal inferences based on cycle threshold values and other features; antemortem testing rates. Results From 1118 decedents enrolled between January and June 2021, COVID-19 was detected among 32.0% (358/1116). Roughly four COVID-19+ community deaths occurred for every facility death. Antemortem testing occurred for 52.6% (302/574) of facility deaths but only 1.8% (10/544) of community deaths and overall, only ∼10% of COVID-19+ deaths were identified in life. During peak transmission periods, COVID-19 was detected in ∼90% of all deaths. We observed three waves of transmission that peaked in July 2020, January 2021 and ∼June 2021: the AE.1 lineage and the Beta and Delta variants, respectively. PCR signals were strongest among those whose deaths were deemed 'probably due to COVID-19', and weakest among children, with an age-dependent increase in PCR signal intensity. Conclusions COVID-19 was common among deceased individuals in Lusaka. Antemortem testing was rarely done, and almost never for community deaths. Suspicion that COVID-19 was the cause of deaths was highest for those with a respiratory syndrome and lowest for individuals <19 years.