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. 2024 Nov 7;15(1):649.
doi: 10.4102/jphia.v15i1.649. eCollection 2024.

High immunity and low mortality after Omicron and mass event in Cameroon despite low vaccination

Yap Boum  1   2   3 , Lucrece Matchim  2 , Dominique K Guimsop  4   5 , Bongkiyung D Buri  2 , Lisa M Bebell  6 , Yuya S F Jaudel  7 , Fai K G Njuwa  2 , Daniel B Danirla  2 , Eric Youm  7 , Rodrigue Ntone  2 , Claudric Roosevelt Tchame  4 , Dora Tchiasso  2 , Rachelle Essaka  8 , Justin B Eyong  2 , Audrey Ngosso  2 , Herwin Nanda  2 , Nsaibirni R Fondze  7 , Mark Ndifon Ndifon  7 , Lucrèce Eteki  2 , Yonta F C Ghislain  2 , Bruno Yannick Eyenga Messi  2 , Hamadou Moustapha  2 , Moustafa Hamdja  2 , René Ghislain Essomba  9 , Nadia Mandeng  1 , Tamakloe A K Modeste  10 , Anne-Cécile Zoung-Kani Bisseck  11 , Sara Irène Eyangoh  12 , Richard Njouom  12 , Marie Claire Okomo  9 , Linda Esso  1   13 , Epee Emilienne  1   4 , Georges-Alain Etoundi Mballa  1   4
Affiliations

High immunity and low mortality after Omicron and mass event in Cameroon despite low vaccination

Yap Boum et al. J Public Health Afr. .

Abstract

Background: Little is known about the evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunity in African communities.

Aim: We evaluated changes in anti-SARS-CoV-2 antibodies, mortality and vaccination status in Cameroon between August 2021 and September 2022 to begin describing the evolution of the pandemic in Africa.

Setting: The study was conducted across Cameroon's 10 regional capitals, between 2021 and 2022 as the country hosted a mass gathering.

Methods: We conducted a cross-sectional population-based survey in 2022, including SARS-CoV-2 seroprevalence testing and retrospective mortality estimation using two-stage cluster sampling. We estimated and compared seroprevalence and crude mortality rates (CMR) to a survey conducted in 2021 using the same methodology.

Results: We performed serologic testing on 8400 individuals and collected mortality data from 22 314 individuals. Approximately 5% in each survey reported SARS-CoV-2-vaccination. Rapid diagnostic test-based seroprevalence increased from 11.2% (95% confidence interval [CI]: 10-12.5) to 59.8% (95% CI: 58.3-61.2) between 2021 and 2022, despite no increase in the proportion vaccinated. The CMR decreased from 0.17 to 0.06 deaths per 10 000 persons per day between 2021 and 2022. In 2022, no deaths were reportedly attributable to COVID-19 as compared to 17 deaths in 2021.

Conclusion: Over a 12-month period encompassing two waves of omicron variant SARS-CoV-2 and a mass gathering, SARS-CoV-2 seropositivity in Cameroon approached 60%, and deaths declined despite low vaccination coverage.

Contribution: This study challenges the assumption that high immunisation coverage is the sole determinant of epidemic control in the African context and encourages policymakers to increasingly rely on local research when designing response strategies for more effective outbreak management.

Keywords: Africa; SARS-CoV-2; immunity; mortality; seroprevalence.

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Conflict of interest statement

The authors declare that they have no financial or personal relationships that may have inappropriately influenced them in writing this article.

Figures

FIGURE 1
FIGURE 1
Unadjusted severe acute respiratory syndrome coronavirus 2 antibody seroprevalence during the two surveys and cumulative incidence of confirmed cases and vaccination in Cameroon, March 2020 – September 2022.
FIGURE 2
FIGURE 2
Monthly number of reported deaths by age group in Cameroon, from January 2019 to November 2022.
See this image and copyright information in PMC

References

    1. Berhan Y. Will Africa be devastated by covid-19 as many predicted? Perspective and prospective. Ethiop J Health Sci. 2020;30(3):459–467. 10.4314/ejhs.v30i3.17 - DOI - PMC - PubMed
    1. Fanidi A, Jouven X, Gaye B. Strategies to control COVID-19 and future pandemics in Africa and around the globe. Eur Heart J. 2020;41(41):3973–3975. 10.1093/eurheartj/ehaa278 - DOI - PMC - PubMed
    1. Does sub-Saharan Africa truly defy the forecasts of the COVID-19 pandemic? Response from population data | medRxiv [homepage on the Internet]. [cited 2023 Jan 06]. Available from: https://www.medrxiv.org/content/10.1101/2020.07.06.20147124v1 - DOI
    1. WHO coronavirus (COVID-19) dashboard with vaccination data [homepage on the Internet]. [cited 2023 Jul 13]. Available from: https://covid19.who.int/table
    1. Salyer SJ, Maeda J, Sembuche S, et al. . The first and second waves of the COVID-19 pandemic in Africa: A cross-sectional study. Lancet. 2021;397(10281):1265–1275. 10.1016/s0140-6736(21)00632-2 - DOI - PMC - PubMed

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