The risk of reinfection from the omicron coronavirus variant is three times higher than for any previous variant, according to a South African study of infections since the start of the pandemic.
The finding provides evidence of omicron’s “ability to evade immunity from prior infection,” according to the authors, Juliet Pulliam of the South African Center for Epidemiological Modelling and Analysis and Harry Moultrie of the National Center for Communicable Diseases.
The study was based on data collected through South Africa’s health system on about 2.8 million confirmed coronavirus infections between March 2020 and Nov. 27, the authors wrote in an emailed statement. Of those, 35,670 were suspected reinfections.
“Our most urgent priority now is to quantify the extent of omicron’s immune escape for both natural and vaccine-derived immunity, as well as its transmissibility relative to other variants and impact on disease severity,” they wrote.
South Africa announced the discovery of a new variant, later named omicron, on Nov. 25 as cases began to spike and the strain spread across the globe. National daily cases almost doubled on Wednesday, days after countries across the world halted flights to and from southern Africa.