COVID-19 Vaccine Uptake and Effectiveness by Time since Vaccination in the Western Cape Province, South Africa: An Observational Cohort Study during 2020-2022

There are few data on the real-world effectiveness of COVID-19 vaccines and boosting in Africa, which experienced widespread SARS-CoV-2 infection before vaccine availability. We assessed the association between vaccination and severe COVID-19 in the Western Cape, South Africa, in an observational co...

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Veröffentlicht in:Vaccines (Basel) 2024-06, Vol.12 (6), p.628
Hauptverfasser: Kassanjee, Reshma, Davies, Mary-Ann, Heekes, Alexa, Mahomed, Hassan, Hawkridge, Anthony J, Morden, Erna, Jacobs, Theuns, Cohen, Cheryl, Moultrie, Harry, Lessells, Richard J, Van Der Walt, Nicolette, Arendse, Juanita O, Wolter, Nicole, Walaza, Sibongile, Jassat, Waasila, von Gottberg, Anne, Hannan, Patrick L, Feikin, Daniel R, Cloete, Keith, Boulle, Andrew
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Sprache:eng
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Zusammenfassung:There are few data on the real-world effectiveness of COVID-19 vaccines and boosting in Africa, which experienced widespread SARS-CoV-2 infection before vaccine availability. We assessed the association between vaccination and severe COVID-19 in the Western Cape, South Africa, in an observational cohort study of >2 million adults during 2020-2022. We described SARS-CoV-2 testing, COVID-19 outcomes, and vaccine uptake over time. We used multivariable cox models to estimate the association of BNT162b2 and Ad26.COV2.S vaccination with COVID-19-related hospitalization and death, adjusting for demographic characteristics, underlying health conditions, socioeconomic status proxies, and healthcare utilization. We found that by the end of 2022, 41% of surviving adults had completed vaccination and 8% had received a booster dose. Recent vaccination was associated with notable reductions in severe COVID-19 during periods dominated by Delta, and Omicron BA.1/2 and BA.4/5 (sub)lineages. During the latest Omicron BA.4/5 wave, within 3 months of vaccination or boosting, BNT162b2 and Ad26.COV2.S were each 84% effective against death (95% CIs: 57-94 and 49-95, respectively). However, distinct reductions of effectiveness occurred at longer times post completing or boosting vaccination. Results highlight the importance of continued emphasis on COVID-19 vaccination and boosting for those at high risk of severe COVID-19, even in settings with widespread infection-induced immunity.
ISSN:2076-393X
2076-393X
DOI:10.3390/vaccines12060628