Study shows Omicron marked a change in the SARS-CoV-2 epidemic curve, clinical profile, and deaths in South Africa

30 May 2022

According to a recent study titled, Clinical severity of COVID-19 in patients admitted to hospital during the omicron wave in South Africa: a retrospective observational study,  published in the journal The Lancet Global Health, the fourth Omicron-dominated wave was far less severe than the preceding three Covid-19 waves that marked a significant shift in the trend of the disease. 

This was likely due to increased immunity from previous SARS CoV-2 infections and vaccinations; and a less severe variant observed the researchers. This retrospective observational study aimed to assess the clinical severity of patients admitted to hospital during the Omicron fourth wave with SARS-CoV-2 infections compared to patients of the previous three waves. 

The findings showed that a lower proportion of patients had severe disease or required hospitalisation. The in-hospital case-fatality ratio and disease severity were almost two-fold higher in the three preceding first waves compared to the Omicron wave. Data on Covid-19 hospital admissions were collected through DATCOV, an active national surveillance database established to monitor Covid-19 hospitalisation; and from daily laboratory reports on rtPCR and antigen-positive SARS-CoV-2 cases.

 “The DATCOV surveillance system has been useful in rapidly providing data on the trends in hospitalisation, severity and mortality, to enable an understanding of the characteristics of new SARS-CoV-2 variants” explained lead author Dr Waasila Jassat of the NICD. 

The authors concluded that Omicron marked a change in the SARS-CoV-2 epidemic curve, clinical profile, and deaths in South Africa and extrapolations to other populations should factor in differing vaccination and previous infection levels.

To read more see: Jassat W, Abdool Karim SS, et al. Lancet Global Health 2022 May. doi: 10.1016/S2214109X(22)001140.   

7-day moving average of new cases, hospital admissions and in-hospital Covid-19 deaths up to – 23-01-2022