Omicron subvariants escape vaccine antibodies, says new study

A new study by Harvard Medical School claims that Omicron subvariants BA.4 and BA.5 appear to escape antibody responses in both those who had an infection and those who were fully vaccinated and boosted.

“We observed three-fold reductions in neutralizing antibody titres induced by vaccination and infection against BA4 and BA5 compared to BA1 and BA2, which are already significantly lower than the original Covid-19 variants,” said Dr. Dan Barouch, an author of the article and director of the Center for Virology and Vaccine Research in Boston, told CNN.

dr. However, Barouch added that Covid-19 vaccines can still provide substantial protection against serious infections and informed CNN that vaccine makers are working on a much stronger booster dose that could challenge stronger variants like Omicron.

Since the outbreak of Covid-19 in China at the end of 2019, as many as five variants – Alpha, Beta, Gamma, Delta and Omicron – have been identified, with Omicron being the most transmissible. It still persists and is still prevalent in many countries, including India, despite the fact that millions have been vaccinated. However, Omicron is considered less contagious because the rate of serious infections and death is relatively low.

Omicron’s subvariants BA.4 and BA.5 are the most rapidly spreading variants reported to date, and according to the European Center for Disease, they are expected to increase transmission in the United States, United Kingdom and the rest of Europe in the coming weeks. dominate. Prevention and control.

The ability of a vaccine or previous infection to neutralize the BA.4 and BA.5 subvariants of Omicron is several times lower compared to the parent coronavirus, according to the study published in the New England Journal of Medicine.

“Our data suggest that these new Omicron subvariants are likely to lead to increases in infections in populations with high vaccine immunity and natural BA1 and BA2 immunity,” wrote Dr. Barouch in the research.

In the study, among 27 study participants who had been vaccinated and boosted with the Pfizer/BioNTech coronavirus vaccine, the researchers found that two weeks after the booster dose, the levels of neutralizing antibodies to Omicron subvariants were much lower than the response to the parent coronavirus.

Neutralizing antibody levels were 6.4-fold lower relative to BA.1; by a factor of 7 against BA.2; by a factor of 14.1 against BA.2.12.1 and by a factor of 21 against BA.4 or BA.5, the researchers described.

Also among 27 participants previously infected with the BA.1 or BA.2 subvariants, median 29 days earlier, the researchers found similar results.

“Our data suggest that Covid-19 still has the ability to mutate further, resulting in increased transmissibility and increased antibody escape,” said the author.

The U.S. Centers for Disease Control and Prevention estimates that 94.7 percent of the U.S. population age 16 and older has antibodies to the coronavirus through vaccination, infection, or both.

However, according to data from the U.S. Centers for Disease Control and Prevention, BA.4 and BA.5 last week led to an estimated 35 percent of new Covid-19 infections in the United States, up from 29 percent the week before.

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