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
Observational Study
. 2023 Feb 21;15(3):597.
doi: 10.3390/v15030597.

Sustained Low Incidence of Severe and Fatal COVID-19 Following Widespread Infection Induced Immunity after the Omicron (BA.1) Dominant in Gauteng, South Africa: An Observational Study

Shabir A Madhi  1   2 , Gaurav Kwatra  1   2 , Jonathan E Myers  3 , Waasila Jassat  4   5 , Nisha Dhar  1 , Christian K Mukendi  1 , Lucille Blumberg  4   5 , Richard Welch  4   5 , Alane Izu  1   2 , Portia C Mutevedzi  1
Affiliations
Observational Study

Sustained Low Incidence of Severe and Fatal COVID-19 Following Widespread Infection Induced Immunity after the Omicron (BA.1) Dominant in Gauteng, South Africa: An Observational Study

Shabir A Madhi et al. Viruses. .

Abstract

We conducted an epidemiologic survey to determine the seroprevalence of SARS-CoV-2 anti-nucleocapsid (anti-N) and anti-spike (anti-S) protein IgG from 1 March to 11 April 2022 after the BA.1-dominant wave had subsided in South Africa and prior to another wave dominated by the BA.4 and BA.5 (BA.4/BA.5) sub-lineages. We also analysed epidemiologic trends in Gauteng Province for cases, hospitalizations, recorded deaths, and excess deaths were evaluated from the inception of the pandemic through 17 November 2022. Despite only 26.7% (1995/7470) of individuals having received a COVID-19 vaccine, the overall seropositivity for SARS-CoV-2 was 90.9% (95% confidence interval (CI), 90.2 to 91.5) at the end of the BA.1 wave, and 64% (95% CI, 61.8 to 65.9) of individuals were infected during the BA.1-dominant wave. The SARS-CoV-2 infection fatality risk was 16.5-22.3 times lower in the BA.1-dominant wave compared with the pre-BA.1 waves for recorded deaths (0.02% vs. 0.33%) and estimated excess mortality (0.03% vs. 0.67%). Although there are ongoing cases of COVID-19 infections, hospitalization and death, there has not been any meaningful resurgence of COVID-19 since the BA.1-dominant wave despite only 37.8% coverage by at least a single dose of COVID-19 vaccine in Gauteng, South Africa.

Keywords: Africa; COVID-19; immunity; infection fatality risk; sero-survey.

PubMed Disclaimer

Conflict of interest statement

S.A.M. reports grants from the Bill & Melinda Gates Foundation during the conduct of the study, grants and personal fees from the Bill & Melinda Gates Foundation, grants from the South African Medical Research Council, grants from Novavax, grants from Pfizer, grants from Minervax, and grants from the European & Developing Countries Clinical Trials Partnership outside the submitted work. G.K., N.D., C.K.M., A.I., and P.C. M report grants from the Bill & Melinda Gates Foundation during the conduct of the study. R.M. has shareholdings in Adcock Ingram Holdings Ltd., Aspen Pharmacare Holdings Ltd., Dischem Pharmacies Ltd., Discovery Ltd., and Netcare Ltd. outside the submitted work. J.E.M., W.J., and L.B. have nothing to disclose.

Figures

Figure 1
Figure 1
Flow of households and participants included in the seroprevalence surveys.
Figure 2
Figure 2
Overall trends of daily incidence per 100,000 recorded COVID-19 cases, hospitalizations and deaths, and excess mortality-attributable COVID-19 deaths for Gauteng, South Africa. Inset figure magnifies COVID-19-recorded deaths and excess mortality.
Figure 3
Figure 3
(A–D): Age-group-stratified analysis of daily moving averages of recorded cases, hospitalizations and deaths in Gauteng Province for each of five COVID-19 waves.
See this image and copyright information in PMC

References

    1. COVID-19 Cumulative Infection Collaborators Estimating global, regional, and national daily and cumulative infections with SARS-CoV-2 through Nov 14, 2021: A statistical analysis. Lancet. 2022;399:2351–2380. doi: 10.1016/S0140-6736(22)00484-6. - DOI - PMC - PubMed
    1. Viana R., Moyo S., Amoako D.G., Tegally H., Scheepers C., Althaus C.L., Anyaneji U.J., Bester P.A., Boni M.F., Chand M., et al. Rapid epidemic expansion of the SARS-CoV-2 Omicron variant in southern Africa. Nature. 2022;603:679–686. doi: 10.1038/s41586-022-04411-y. - DOI - PMC - PubMed
    1. Nishiura H., Ito K., Anzai A., Kobayashi T., Piantham C., Rodríguez-Morales A.J. Relative Reproduction Number of SARS-CoV-2 Omicron (B.1.1.529) Compared with Delta Variant in South Africa. J. Clin. Med. 2021;11:30. doi: 10.3390/jcm11010030. - DOI - PMC - PubMed
    1. Rössler A., Riepler L., Bante D., Laer D., Kimpel J. SARS-CoV-2 Omicron Variant Neutralization in Serum from Vaccinated and Convalescent Persons. N. Engl. J. Med. 2022;386:698–700. doi: 10.1056/NEJMc2119236. - DOI - PMC - PubMed
    1. Mazzoni A., Vanni A., Spinicci M., Capone M., Lamacchia G., Salvati L., Coppi M., Antonelli A., Carnasciali A., Farahvachi P., et al. SARS-CoV-2 Spike-Specific CD4+ T Cell Response Is Conserved Against Variants of Concern, Including Omicron. Front. Immunol. 2022;13:801431. doi: 10.3389/fimmu.2022.801431. - DOI - PMC - PubMed

Publication types

Substances