Antibodies Induced by COVID-19 Vaccine Less Effective Against Certain Coronavirus Variants: Study

BOSTON: Antibodies produced by some COVID-19 vaccines are less effective at neutralizing new circulating variants of the novel coronavirus, such as those first reported in UK, South Africa and Brazil, new study finds .
The research, published in the journal Cell, noted that the neutralizing antibodies induced by the Pfizer and Moderna COVID-19 vaccines were less effective against the coronavirus variants first described in Brazil and South Africa.
According to scientists, including Alejandro Balazs of Massachusetts General Hospital (MGH) in the United States, neutralizing antibodies work by binding tightly to the virus and preventing it from entering cells, preventing infection.
They said this binding only occurs when the antibody and virus forms are perfectly matched to each other “like a key in a lock.
If the shape of the virus changes where the antibody attaches to it – in this case, in the spike protein of the novel coronavirus – they said the antibody may no longer be able to recognize and neutralize the virus as well.
In the study, researchers developed tests for COVID-19, comparing the effectiveness of antibodies against the original strain versus newer variants.
“When we tested these new strains against vaccine-induced neutralizing antibodies, we found that the three new strains first described in South Africa were 20 to 40 times more resistant to neutralization,” Balazs said, also an assistant professor of medicine at Harvard. School of Medicine in the United States.
Scientists said the two strains first described in Brazil and Japan were five to seven times more resistant than the original SARS-CoV-2 virus line from Wuhan, China.
“In particular, we found that mutations in a specific part of the spike protein called the receptor binding domain were more likely to help the virus resist neutralizing antibodies,” said Wilfredo Garcia-Beltran, lead author of the study of MGH.
The study noted that the three South African variants, which were the most resistant, all shared three mutations in the receptor binding domain, which could contribute to their high resistance to neutralizing antibodies.
However, the scientists said that the ability of these variants to resist neutralizing antibodies does not mean that the vaccines will not be effective.
“The body has other methods of immune protection besides antibodies. Our results don’t necessarily mean that vaccines won’t prevent COVID, just that the antibody part of the immune response may have trouble recognizing some of these newer variants, ”Balazs said.
The researchers added that understanding which mutations are most likely to allow the virus to evade vaccine-derived immunity is critical to developing next-generation vaccines capable of providing protection against new variants.
They said it could also help researchers develop more effective preventive methods, such as broadly protective vaccines that work against a wide variety of variants, regardless of which mutations develop. (AGENCIES)