Vaccine-induced antibodies may be less effective against several new SARS-CoV-2 variants: study

SARS-CoV-2, the virus that causes COVID-19, has mutated throughout the pandemic. New variants of the virus have emerged around the world, including variants that have the ability to spread or evade the immune system. Such variants have been identified in California, Denmark, the United Kingdom, South Africa and Brazil / Japan. Understanding how well COVID-19 vaccines work against these variants is crucial in efforts to stop the global pandemic, and it is the subject of new research from the Ragon Institute of MGH, MIT and Harvard and Massachusetts General Hospital.

In a recent study in Cell, Ragon Core Member Alejandro Balazs, Ph.D., found that the neutralizing antibodies induced by the Pfizer and Modern COVID-19 vaccines were significantly less effective compared to the variants first described in Brazil / Japan and South Africa. Balazs’ team uses their experience to measure HIV-neutralizing antibodies to create similar tests for COVID-19, and compares how well the antibodies work at the original voltage versus the new variants.

“We were able to leverage the unique high throughput capacity that already exists and apply it to SARS-CoV-2,” said Balazs, who is also an assistant professor of medicine at Harvard Medical School and an assistant researcher in the Department of Medicine at MGH. . “When we tested these new strains against neutralizing antibodies induced by vaccine, we found that the three new strains first described in South Africa are 20-40 times more resistant to neutralization, and that the two strains first described in Brazil and Japan were five to seven times more resistant than the original SARS-CoV-2 virus. “

Balazs neutralize antibodies by binding to the virus and preventing it from entering the cells and thus preventing infection. Like a key in a lock, this binding only takes place when the shape of the antibody and the shape of the virus fit together perfectly. If the form of the virus changes where the antibody attaches to it – in this case in SARS-CoV-2’s ear protein – the antibody may also no longer recognize and neutralize the virus. The virus can then be described as resistant to neutralization.

“In particular,” says Wilfredo Garcia-Beltran, MD, Ph.D., a resident physician in the Department of Pathology at MGH and first author of the study, “we found that mutations in a specific part of the vein protein the receptor binding domain is more likely to help the virus resist the neutralizing antibodies. “The three South African variants, which were the most resistant, all shared three mutations in the receptor binding domain. This may contribute to their high resistance to neutralizing antibodies.

Currently, all approved COVID-19 vaccines work by teaching the body to produce an immune response, including antibodies, against the SARS-CoV-2 ear protein. Although the ability of these variants to resist neutralizing antibodies is important, it does not mean that the vaccines will not be effective.

“The body has other immune protection methods besides antibodies,” says Balazs. “Our findings do not necessarily mean that COVID vaccines will not occur, but only that the antibody portion of the immune response is having difficulty recognizing some of these new variants.”

Like all viruses, SARS-CoV-2 is expected to continue to change as it spreads. Understanding which mutations the virus is likely to evade vaccine immunity can help researchers develop next-generation vaccines that can provide protection against new variants. It can also help researchers develop more effective prevention methods, such as broad-spectrum protective vaccines that work against a wide range of variants, regardless of which mutations develop.

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