Omicron Variant May Overcome Prior COVID-19 Infection

People who have already had COVID-19 have a higher risk of reinfection with the omicron coronavirus variant than with earlier variants, new research shows. The South African scientists who reported the findings believe that vaccination will have the power to stop severe illness, however.

Speaking at a World Health Organization briefing, study team member Anne von Gottberg, M.B., B.Ch., Ph.D., of the University of Witwatersrand in Johannesburg, said she and her colleagues tracked COVID-19 reinfections in South Africa. They found a jump in repeat infections with the new omicron variant that did not occur when two previous variants -- including delta -- swept through the country, the Associated Press reported.

The study did not say what portion of the reinfections were confirmed as Omicron cases or whether they caused serious illness. Experts have been surprised by the sheer number of mutations in the omicron variant, and there has been concern that such changes might render it less vulnerable to antibodies generated by prior infection or vaccination.

The South African findings were posted online Thursday. They are considered preliminary and have not yet undergone scientific review, the AP reported.

"Previous infection used to protect against delta and now with omicron it doesn't seem to be the case," said von Gottberg at the WHO briefing. While the researchers did not examine how effective vaccines might be against omicron, von Gottberg said they "believe that vaccines will still, however, protect against severe disease."

The study suggests that "omicron will be able to overcome natural and probably vaccine-induced immunity to a significant degree," Paul Hunter, M.D., of the University of East Anglia in England, said in a written response to the findings, the AP reported. But just how much "is still unclear though it is doubtful that this will represent complete escape."