Prior COVID infections offer less protection against omicron variant
A new study suggests that people who have already had COVID-19 appear to be less protected from being reinfected with the omicron variant than with previous variants. A group of South African scientists set out to examine the risk of COVID reinfection with the emergence of the omicron variant in the country. After looking at data of reinfection caused by the beta, delta and omicron variants, they found that past infections might not protect against omicron as well as they protected against the last two variants.
“Population-level evidence suggests that the omicron variant is associated with substantial ability to evade immunity from prior infection,” the authors said. “In contrast, there is no population-wide epidemiological evidence of immune escape associated with the beta or delta variants,” they added.
The study, titled “Increased risk of SARS-CoV-2 reinfection associated with emergence of the omicron variant in South Africa,” was published Thursday. Researchers didn’t say how serious the reinfections were, or how much vaccines protect against the new variant.
“Previous infection used to protect against delta and now with omicron it doesn’t seem to be the case,” one of the researchers, Anne von Gottberg, a microbiologist, said at a World Health Organization briefing on Thursday. However, “we believe that vaccines will still, however, protect against severe disease,” she added.
The study’s findings have “important implications for public health planning, particularly in countries like South Africa with high rates of immunity from prior infection,” the authors wrote. Omicron was discovered just over a week ago by scientists in South Africa and Botswana.
On Friday, WHO officials said that the variant is now present in 38 countries, up from 23 just two days ago, with early data suggesting the strain is more contagious than delta.
“There is a suggestion that there is increased transmissibility. What we need to understand is if it’s more or less transmissible compared to delta,” Maria Van Kerkhove, WHO’s COVID-19 technical lead, said during a live-streamed Q&A session.