Scientists have known since early in the pandemic that the immunity gained from a coronavirus infection is not total, and probably not permanent, and that some people are reinfected. Even so, with a huge number of people already infected and recovered — about 260 million worldwide that have been detected, and in reality far more, experts say — whatever protection they had looked like an important layer in the world’s defenses.
The new variant calls that into question.
Scientists in South Africa have reported a sudden, sharp rise in November in coronavirus cases among people in that country who had already been infected, in a study that has not yet been reviewed and published by a scientific journal. The authors noted that there was no such upswing when the Beta and Delta variants emerged.
They did not say how many of those reinfections could be attributed to Omicron, but South Africa’s National Institute for Communicable Diseases reported on [December 1] that when it conducted a genetic analysis on a sampling of coronavirus-positive test results from November, almost three-quarters were the new variant.
“Population-level evidence suggests that the Omicron variant is associated with substantial ability to evade immunity from prior infection,” the authors of the unpublished study wrote.
