A study conducted by South African researchers on the basis of surveillance data has found that there is an increased risk of Covid-19 reinfection associated with the new Omicron variant of coronavirus. This is the first data-based study to suggest that Omicron may evade immunity from prior infection.
“Population-level evidence suggests that the Omicron variant is associated with substantial ability to evade immunity from prior infection. In contrast, there is no population-wide epidemiological evidence of immune escape associated with the Beta or Delta variants,” the study states.
The study infers that the spread of the Beta and Delta variants of Covid-19 was due to increased transmissibility, rather than ability to evade immunity.
“We find evidence of a substantial and ongoing increase in the risk of reinfection that is temporally consistent with the timing of the emergence of the Omicron variant in South African, suggesting that its selection advantage is at least partially driven by an increased ability to infect previously infected individuals,” the researchers observed.
The study, which has not yet been peer-reviewed, concludes that the increased risk of reinfection that Omicron poses can have important implications for public health planning, especially in nations which have developed high rates of immunity via prior infection. It is not yet known whether Omicron can also evade vaccine-induced immunity.