Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jul:12:e00802.
doi: 10.1016/j.sciaf.2021.e00802. Epub 2021 May 30.

Serologic response to SARS-CoV-2 in an African population

Karl Njuwa Fai  1 , Tchoula Mamiafo Corine  1 , Lisa M Bebell  2 , Akenji Blaise Mboringong  3 , E B P Taa Nguimbis  1 , Robert Nsaibirni  1 , Nicole Fouda Mbarga  1 , Lucrece Eteki  1 , Birgit Nikolay  4 , Rene Ghislain Essomba  3   5 , Mark Ndifon  1 , Rodrigue Ntone  1 , Achta Hamadou  6 , Lucrece Matchim  1 , Dora Tchiasso  1 , Aristide S Abah Abah  6 , Rachel Essaka  7 , Solange Peppa  3 , Fouda Crescence  3 , Jean Patrick Ouamba  8 , Modeste Tamakloé Koku  8 , Nadia Mandeng  6 , Mahamat Fanne  6 , Sarah Eyangoh  9 , Georges Alain Etoundi Mballa  6 , Linda Esso  6 , Emilienne Epée  6 , Richard Njouom  9 , Marie-Claire Okomo Assoumou  3   5 , Yap Boum  1   6   5
Affiliations

Serologic response to SARS-CoV-2 in an African population

Karl Njuwa Fai et al. Sci Afr. 2021 Jul.

Abstract

Official case counts suggest Africa has not seen the expected burden of COVID-19 as predicted by international health agencies, and the proportion of asymptomatic patients, disease severity, and mortality burden differ significantly in Africa from what has been observed elsewhere. Testing for SARS-CoV-2 was extremely limited early in the pandemic and likely led to under-reporting of cases leaving important gaps in our understanding of transmission and disease characteristics in the African context. SARS-CoV-2 antibody prevalence and serologic response data could help quantify the burden of COVID-19 disease in Africa to address this knowledge gap and guide future outbreak response, adapted to the local context. However, such data are widely lacking in Africa. We conducted a cross-sectional seroprevalence survey among 1,192 individuals seeking COVID-19 screening and testing in central Cameroon using the Innovita antibody-based rapid diagnostic. Overall immunoglobulin prevalence was 32%, IgM prevalence was 20%, and IgG prevalence was 24%. IgM positivity gradually increased, peaking around symptom day 20. IgG positivity was similar, gradually increasing over the first 10 days of symptoms, then increasing rapidly to 30 days and beyond. These findings highlight the importance of diagnostic testing and asymptomatic SARS-CoV-2 transmission in Cameroon, which likely resulted in artificially low case counts. Rapid antibody tests are a useful diagnostic modality for seroprevalence surveys and infection diagnosis starting 5-7 days after symptom onset. These results represent the first step towards better understanding the SARS-CoV-2 immunological response in African populations.

Keywords: Africa; COVID-19; Immunoglobulin; Rapid diagnostic tests; Serology.

PubMed Disclaimer

Conflict of interest statement

We declare no competing interests.

Figures

Fig1
Fig.1
Flow chart for study visits and inclusions.
Fig 2
Fig. 2
Comparison of SARS-CoV-2 serologic and PCR test positivity by days since symptom onset.
Fig 3
Fig. 3
IgM and IgG antibody positivity by days since symptom onset.
See this image and copyright information in PMC

References

    1. Zhu N., Zhang N., Wang N., et al. A novel coronavirus from patients with pneumonia in China, 2019. N. Engl. J. Med. 2020;382:727–733. - PMC - PubMed
    1. A. Fontanet, S. Cauchemez. COVID-19 herd immunity: where are we? [Internet]. Vol. 20, Nature Reviews Immunology. Nature Research; 2020 [cited 2020 Oct 4]. Available from: https://pubmed.ncbi.nlm.nih.gov/32908300/. - PMC - PubMed
    1. Britton T., Ball F., Trapman P. A mathematical model reveals the influence of population heterogeneity on herd immunity to SARS-CoV-2. Science (80-) [Internet] 2020 Aug;369(6505):846–849. https://pubmed.ncbi.nlm.nih.gov/32576668/ [cited 2020 Oct 4]Available from: - PMC - PubMed
    1. Randolph H.E., Barreiro L.B. Cell Press; 2020. Herd Immunity: Understanding COVID-19 [Internet] pp. 737–741. Vol. 52, Immunity[cited 2020 Oct 4]Available from: /pmc/articles/PMC7236739/?report=abstract. - PMC - PubMed
    1. Frederiksen L.S.F., Zhang Y., Foged C., Thakur A. Frontiers Media S.A.; 2020. The Long Road Toward COVID-19 Herd Immunity: Vaccine Platform Technologies and Mass Immunization Strategies [Internet]https://pubmed.ncbi.nlm.nih.gov/32793245/ Vol. 11, Frontiers in Immunology[cited 2020 Oct 4]. Available from. - PMC - PubMed

LinkOut - more resources