Decreased severity of disease during the first global omicron variant covid-19 outbreak in a large hospital in tshwane, south africa

•the rapid rise and decline of admissions and decreased severity of COVID-19 disease•compares 466 patients in the Omicron wave to 3962 patients in previous waves•describes disease severity of all admitted patients at peak bed occupancy•a lower mortality rate from Omicron compared to previous waves The coronavirus disease 2019 (COVID-19) first reported in Wuhan, China in December 2019 is a global pandemic that is threatening the health and wellbeing of people worldwide. To date there have been more than 274 million reported cases and 5.3 million deaths. The Omicron variant first documented in the City of Tshwane, Gauteng Province, South Africa on 9 November 2021 led to exponential increases in cases and a sharp rise in hospital admissions. The clinical profile of patients admitted at a large hospital in Tshwane is compared with previous waves. 466 hospital COVID-19 admissions since 14 November 2021 were compared to 3962 admissions since 4 May 2020, prior to the Omicron outbreak. Ninety-eight patient records at peak bed occupancy during the outbreak were reviewed for primary indication for admission, clinical severity, oxygen supplementation level, vaccination and prior COVID-19 infection. Provincial and city-wide daily cases and reported deaths, hospital admissions and excess deaths data were sourced from the National Institute for Communicable Diseases, the National Department of Health and the South African Medical Research Council. For the Omicron and previous waves, deaths and ICU admissions were 4.5% vs 21.3% (p