High SARS-CoV-2 seroprevalence in health care workers but relatively low numbers of deaths in urban Malawi

  1. Marah G. Chibwana
  2. Khuzwayo C. Jere
  3. Raphael Kamng'ona
  4. Jonathan Mandolo
  5. Vincent Katunga-Phiri
  6. Dumizulu Tembo
  7. Ndaona Mitole
  8. Samantha Musasa
  9. Simon Sichone
  10. Agness Lakudzala
  11. Lusako Sibale
  12. Prisca Matambo
  13. Innocent Kadwala
  14. Rachel L. Byrne
  15. Alice Mbewe
  16. Marc Y. R. Henrion
  17. Ben Morton
  18. Chimota Phiri
  19. Jane Mallewa
  20. Henry C. Mwandumba
  21. Emily R. Adams
  22. Stephen B. Gordon
  23. Kondwani C. Jambo

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Abstract

Background : In low-income countries, like Malawi, important public health measures including social distancing or a lockdown have been challenging to implement owing to socioeconomic constraints, leading to predictions that the COVID-19 pandemic would progress rapidly. However, due to limited capacity to test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, there are no reliable estimates of the true burden of infection and death.  We, therefore, conducted a SARS-CoV-2 serosurvey amongst health care workers (HCWs) in Blantyre city to estimate the cumulative incidence of SARS-CoV-2 infection in urban Malawi.

Methods : We recruited 500 otherwise asymptomatic HCWs from Blantyre City (Malawi) from 22 nd May 2020 to 19 th June 2020 and serum samples were collected from all participants. A commercial ELISA was used to measure SARS-CoV-2 IgG antibodies in serum.

Results : A total of 84 participants tested positive for SARS-CoV-2 antibodies. The HCWs with positive SARS-CoV-2 antibody results came from different parts of the city. The adjusted seroprevalence of SARS-CoV-2 antibodies was 12.3% [CI 8.2 - 16.5]. Using age-stratified infection fatality estimates reported from elsewhere, we found that at the observed adjusted seroprevalence, the number of predicted deaths was eight times the number of reported deaths.

Conclusions : The high seroprevalence of SARS-CoV-2 antibodies among HCWs and the discrepancy in the predicted versus reported deaths suggests that there was early exposure but slow progression of COVID-19 epidemic in urban Malawi. This highlights the urgent need for development of locally parameterised mathematical models to more accurately predict the trajectory of the epidemic in sub-Saharan Africa for better evidence-based policy decisions and public health response planning.

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    SciScore for 10.1101/2020.07.30.20164970: (What is this?)

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    Table 1: Rigor

    Institutional Review Board StatementIRB: Ethical statement: Ethical approval was provided by the College of Medicine Research and Ethics Committee (COMREC, Malawi) (P.05/20/3045) and Liverpool School of Tropical Medicine (LSTM, UK) (20-043).
    Consent: All participants gave informed written consent.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Statistical analysis: Graphical presentation was performed using GraphPad Prism 8 (GraphPad Software, USA).
    GraphPad Prism
    suggested: (GraphPad Prism, RRID:SCR_002798)
    GraphPad
    suggested: (GraphPad Prism, RRID:SCR_002798)
    The geospatial data was plotted in R (v4.0.0) using ggmap (v3.0.0) (8) and ggplot2 (v3.3.1) (9).
    ggplot2
    suggested: (ggplot2, RRID:SCR_014601)

    Results from OddPub: Thank you for sharing your data.

    Results from LimitationRecognizer: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

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  2. Version published to 10.12688/wellcomeopenres.16188.2
  3. Version published to 10.12688/wellcomeopenres.16188.1
  4. Version published to 10.1101/2020.07.30.20164970v3 on medRxiv
  5. Version published to 10.1101/2020.07.30.20164970v2 on medRxiv
  6. Version published to 10.1101/2020.07.30.20164970v1 on medRxiv