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Scanning electron micrograph of a cell (purple) infected with the omicron strain of SARS-CoV-2 virus particles (orange), isolated from a patient sample and colorized. Image Credit: NIAID/NIH |
Three currently circulating omicron subvariants of SARS-CoV-2 – including two that currently make up almost 50% of reported COVID-19 infections in the U.S. – are better at evading vaccine- and infection-generated neutralizing antibodies than earlier versions of omicron, new research suggests.
Scientists tested neutralizing antibodies in blood serum samples from vaccinated and once-boosted or recently infected health care professionals against several subvariants in circulation. Three subvariants stood out for their resistance to the antibody immune response: BQ.1, BQ.1.1 and BA.2.75.2.
BQ.1 and BQ.1.1 are subvariants of the BA.4/5 omicron variants that have been dominating the last few months in the U.S., and each now accounts for about a quarter of current infections, according to the Centers for Disease Control and Prevention (CDC). BA.2.75.2, a mutant of the BA.2 omicron variant, was the best of all variants tested at evading neutralizing antibodies, but currently accounts for only a very small proportion of reported illnesses in the United States.
“In general, the subvariants BQ.1 and BQ.1.1 are much better compared to prior variants at evading the booster-mediated antibody response – the neutralizing antibody titers are clearly much lower. And those two variants are becoming dominant,” said Shan-Lu Liu, senior author the study and a virology professor in the Department of Veterinary Biosciences at The Ohio State University.