People infected with the earliest version of the Omicron variant of the coronavirus, first identified in South Africa in November, may be vulnerable to reinfection with later versions of Omicron even if they have been vaccinated and boosted, new findings suggest.
Vaccinated patients with Omicron BA.1 breakthrough infections developed antibodies that could neutralise that virus plus the original SARS-CoV-2 virus, but the Omicron sublineages circulating now have mutations that allow them to evade those antibodies, researchers from China reported on Friday in Nature.
Omicron BA.2.12.1, which is presently causing most infections in the United States, and Omicron BA.5 and BA.4, which now account for more than 21% of new U.S. cases, contain mutations not present in the BA.1 and BA.2 versions of Omicron.
