People who've 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, 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 didn't occur when two previous variants -- including Delta -- swept through the country, the Associated Press reported.
The study didn't 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's 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 didn't 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, a professor of medicine from 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," Hunter added.
In the United States, the nation's top expert on infectious disease, Dr. Anthony Fauci, also believes that vaccines plus booster shots should offer protection.
"Although partial immune escape may occur, vaccines, and particularly boosters, give a level of antibody that even with variants like Delta give you a degree of cross-protection, particularly against severe disease," Fauci said on Tuesday.
So far a total of nine cases of coronavirus infection tied to the Omicron variant have been detected in the United States, with cases occurring in California, Colorado, Hawaii, Minnesota and New York, according to CBS News.
In the meantime, President Joe Biden on Thursday announced a new round of measures to protect Americans against the spread of coronavirus variants such as Omicron as winter approaches.
The strategy will include making rapid at-home COVID-19 tests free for more people, extending rules on mask wearing on planes and other modes of transport, launching public awareness campaigns on vaccinations and booster shots, starting family mobile vaccination clinics, and implementing tougher testing requirements for travelers arriving in the country.
Visit the U.S. Centers for Disease Control and Prevention for more on COVID variants.
SOURCES: Associated Press, CBS News