Covid-19: South African study suggests Omicron less severe even for unvaccinated

Omicron globally has tended to cause less severe disease, and proportionally fewer hospital admissions and deaths

By Reuters

Published: Sat 15 Jan 2022, 12:23 PM

Unvaccinated people infected with the Omicron variant of coronavirus may be less prone to severe illness and requiring hospital care or dying than was the case with previous variants, a South African study showed on Friday.

The study, by the National Institute of Communicable Diseases (NICD) in the Western Cape region, which has not yet been peer-reviewed, compared about 11,600 patients from the first three Covid-19 waves with about 5,100 from the Omicron-driven wave that began in November.

Omicron globally has tended to cause less severe disease, and proportionally fewer hospital admissions and deaths, than previous variants.

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Scientists are trying to determine the extent to which this is because of higher immunity rates engendered by vaccination or past illness, or Omicron is intrinsically less nasty.

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The study concluded that about a quarter of the reduced risk of severe disease with Omicron was attributable to characteristics of the virus itself.

"In the Omicron-driven wave, severe Covid-19 outcomes were reduced mostly due to protection conferred by prior infection and/or vaccination, but intrinsically reduced virulence may account for an approximately 25 per cent reduced risk of severe hospitalisation or death compared to Delta," the study said.