The newer Omicron subvariants of SARS-CoV-2 substantially escape neutralizing antibodies induced by both vaccination and previous infection, according to a study published in the New England Journal of Medicine. The study provides the immunological context for current peaks among populations with high vaccination rates and previous infections, the researchers said.
Since the first highly contagious SARS-CoV-2 Omicron variant — known as BA.1 — of COVID-19 emerged last year, the new subvariants continue to evolve. The researchers from the Beth Israel Deaconess Medical Center (BIDMC) in Israel evaluated the antibody response to multiple SARS-CoV-2 Omicron subvariants in 27 vaccinated and boosted individuals and 27 individuals who had previously contracted COVID-19.
They found that the three Omicron subvariants BA.2.12.1, BA.4 and BA.5 substantially escape neutralizing antibodies induced by both vaccination and previous infection. Neutralizing antibody responses to BA.4 and BA.5 were approximately 20 fold lower than on the original WA1/2020 strain and were 3 fold lower than on the Omicron BA.1 and BA.2 variants.
“Our findings suggest that the Omicron variants have continued to evolve,” said senior author Dan H Barouch, director of the Center for Vaccine and Virology Research at BIDMC. “This has important public health implications and provides the immunological context for current increases among populations with high vaccination rates and previous infections, Barouch said.
The researchers noted that new variants emerging may be more transmissible and may more effectively evade the immune protection of previous infection or vaccination.
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