Omicron carries less risk of hospitalization vs. Delta, study suggests
Global News
Questions about Omicron's virulence are at the heart of scientific and political debate in many countries, as governments grapple with how to respond to the spread of the variant.
A South African study suggests reduced risks of hospitalization and severe disease in people infected with the Omicron coronavirus variant versus the Delta one, though the authors say some of that is likely due to high population immunity.
Questions about Omicron’s virulence are at the heart of scientific and political debate in many countries, as governments grapple with how to respond to the spread of the variant while researchers race to understand it.
The new study, which has not been peer-reviewed, sought to assess the severity of disease by comparing data about Omicron infections in October and November with data about Delta infections between April and November, all in South Africa.
The analysis was carried out by a group of scientists from the National Institute for Communicable Diseases (NICD) and major universities including University of the Witwatersrand and University of KwaZulu-Natal.
They used data from four sources: national COVID-19 case data reported to the NICD, public sector laboratories, one large private sector lab and genome data for clinical specimens sent to NICD from private and public diagnostic labs across the country.
The authors found the risk of hospital admission was roughly 80 per cent lower for those infected with Omicron compared with Delta, and that for those in hospital the risk of severe disease was roughly 30 per cent lower.
However, they included several caveats and cautioned against jumping to conclusions about the intrinsic characteristics of Omicron.
“It is difficult to disentangle the relative contribution of high levels of previous population immunity versus intrinsic lower virulence to the observed lower disease severity,” they wrote.