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. 2022 Mar:116:157-165.
doi: 10.1016/j.ijid.2021.12.336. Epub 2021 Dec 17.

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

C Meinus  1 , R Singer  2 , B Nandi  3 , O Jagot  4 , B Becker-Ziaja  2 , B Karo  2 , B Mvula  5 , A Jansen  2 , J Baumann  2 , A Schultz  6
Affiliations

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

C Meinus et al. Int J Infect Dis. 2022 Mar.

Abstract

Background: 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.

Methods: 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.

Findings: 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.

Interpretation: 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.

Keywords: Africa; COVID-19; Malawi; immunity; prevalence; serosurvey.

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Conflict of interest statement

AS is staff member of GIZ German development who partly funded the study. RS, BB, BK and AJ are staff members of RKI Germany who gave technical and material support. All remaining authors declare no competing interests.

AS had full access to all the data in the study and had final responsibility for the decision to submit for publication.

Figures

Figure 1
Figure 1
Participants flow chart
Figure 2
Figure 2
SARS-CoV-2 prevalence with 95% CI
See this image and copyright information in PMC

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