A prior COVID-19 infection may not offer protection against the Omicron variant as it did with the Delta variant.
Dr Anne Von Gottberg, a microbiologist from South Africa's National Institute for Communicable Diseases, said at a news briefing organized by the World Health Organization on Thursday that the country is seeing an increase in breakthrough infections.
'Previous infection used to protect against Delta, but now with Omicron that doesn't seem to be the case,' she said.
'We monitored these reinfection for the Beta [variant] and for the Delta wave, and we didn't see an increase in reinfections over and above what we expect when the force of infection changes, when the wave stops.
'However we are seeing an increase for Omicron.'
Dr Anne Von Gottberg, a microbiologist from South Africa's National Institute for Communicable Diseases, said on Thursday (above) that a previous COVID-19 infection may not protect against the Omicron variant
It comes as COVID-19 cases in South Africa have risen dramatically from 500 per day two weeks ago to 11,535 per day on Thursday
Von Gottberg did not specify the rate of Omicron reinfections compared to the rate of Delta reinfections, just the rate was higher for the new variant.
But she did add that a past infection should still protect against severe disease, hospitalization and death from a new infection.
The Omicron variant was first identified by South African researchers last week and is believed to have originated in Botswana or in Europe.
It has 50 mutations, more than 30 of which are on the spike protein, used by the coronavirus to enter and infect cells.
By comparison, the Delta variant - still the predominant variant in the U.S. - has seven mutations on the spike protein.
Early evidence suggests it is more transmissible than previous variants but it is unclear if it causes more severe illness or death.
Nearly 400 cases have been detected in 32 countries, including the U.S., the UK
