Data suggest that seropositivity was widespread in South Africa before the Omicron wave and the higher infection rates during the Omicron surge were not associated with a corresponding increase in hospitalizations and deaths.

Researchers reported that there was 73.1% seropositivity in Gauteng province between October 22 and December 9, 2021 (95% CI 72.0-74.1). This included 68.4% seroprevalence among unvaccinated people and 93.1% among those who were vaccinated against COVID-19 (RR 1.36, 95% CI 1.33-1.39). Epidemiologic data also suggested that the Omicron wave was tied to a minority of hospital admissions, recorded deaths, and excess deaths due to COVID-19 since the start of the pandemic (11.2%, 3.9%, and 3.3%, respectively). The findings are published in the New England Journal of Medicine.