BOSTON: Antibodies produced by some Covid-19 vaccines are less effective at neutralizing new circulating variants of the new coronavirus, such as those first reported in the UK, South Africa and Brazil, according to a new study.
The research, published in the journal Cell, noted that 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 closely to the virus and preventing it from entering cells, thus preventing infection.
They said this binding only occurs when the antibody and virus forms combine perfectly with each other “like a key in a lock.”
If the shape of the virus changes where the antibody attaches to it (in this case, the tip protein of the new coronavirus), they said the antibody may no longer be able to recognize and neutralize the virus.
In the study, researchers developed assays for Covid-19, comparing the performance of antibodies against the original strain and new 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 20-40 times more resistant to neutralization,” said Balazs, who is also a professor. medical assistant at Harvard Medical School in the USA.
According to the scientists, the two strains first described in Brazil and Japan were five to seven times more resistant, compared to the original SARS-CoV-2 virus lineage in 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, first author of the MGH study.
The study noted that the three South African variants, which were the most resistant, shared all three mutations in the receptor-binding domain, which may contribute to their high resistance to neutralizing antibodies.
However, scientists said that the ability of these variants to resist neutralizing antibodies does not mean that vaccines are not effective.
“The body has other methods of immune protection in addition to antibodies. Our findings do not necessarily mean that vaccines do not prevent Covid, but that the antibody part of the immune response may have trouble recognizing some of these new variants. Balazs said.
The researchers added that understanding which mutations are most likely to allow the virus to evade vaccine-derived immunity is essential to developing next-generation vaccines that can provide protection against new variants.
They said this can also help researchers develop more effective preventive methods, such as widely protective vaccines that work against a wide variety of variants, regardless of the mutations that develop.
The research, published in the journal Cell, noted that 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 closely to the virus and preventing it from entering cells, thus preventing infection.
They said this binding only occurs when the antibody and virus forms combine perfectly with each other “like a key in a lock.”
If the shape of the virus changes where the antibody attaches to it (in this case, the tip protein of the new coronavirus), they said the antibody may no longer be able to recognize and neutralize the virus.
In the study, researchers developed assays for Covid-19, comparing the performance of antibodies against the original strain and new 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 20-40 times more resistant to neutralization,” said Balazs, who is also a professor. medical assistant at Harvard Medical School in the USA.
According to the scientists, the two strains first described in Brazil and Japan were five to seven times more resistant, compared to the original SARS-CoV-2 virus lineage in 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, first author of the MGH study.
The study noted that the three South African variants, which were the most resistant, shared all three mutations in the receptor-binding domain, which may contribute to their high resistance to neutralizing antibodies.
However, scientists said that the ability of these variants to resist neutralizing antibodies does not mean that vaccines are not effective.
“The body has other methods of immune protection in addition to antibodies. Our findings do not necessarily mean that vaccines do not prevent Covid, but that the antibody part of the immune response may have trouble recognizing some of these new variants. Balazs said.
The researchers added that understanding which mutations are most likely to allow the virus to evade vaccine-derived immunity is essential to developing next-generation vaccines that can provide protection against new variants.
They said this can also help researchers develop more effective preventive methods, such as widely protective vaccines that work against a wide variety of variants, regardless of the mutations that develop.