Antibodies raised by COVID-19 vaccine less effective against some coronavirus variants: Study – Times of India

According to a new study, antibodies induced by some COVID-19 vaccines are less effective at neutralising the new circulating variants of the novel coronavirus, such as the ones reported in the UK, Brazil and South Africa.

The study was published in the journal Cell and noted that the neutralising antibodies induced by the Pfizer and Moderna COVID 19 vaccines were less effective against the coronavirus variants first found in South Africa and Brazil.

As per the scientists, neutralising antibodies work by binding tightly to the virus and blocking it from entering the cells and thus preventing infection. That said, this binding only happens when the antibodies and viruses perfectly match, like a key in a lock.

If the shape of the virus changes when the antibody attaches to it, the antibody may no longer be able to recognise and neutralise the virus.

The scientists compared how well the antibodies worked against the original strain versus the new variants.

When the scientists tested the new strains against vaccine-induced neutralising antibodies, they found the three new strains first described in South Africa were 20-40 times more resistant to neutralisation.

The two strains first described in Brazil and japan were five to seven times more resistant as compared to the original SARS-CoV-2 virus lineage 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 the neutralizing antibodies,” said one author of the study.

However, the ability of these variants to resist neutralising antibodies doesn’t mean the vaccines won’t be effective.

“The body has other methods of immune protection besides antibodies. Our findings don’t necessarily mean that vaccines won’t prevent COVID, only that the antibody portion of the immune response may have trouble recognizing some of these new variants,” said the scientists.

To develop the next generation it’s important to understand which mutations are more likely to allow the virus to evade vaccine-derived immunity.

The study can also help researchers develop more effective preventative methods, such as a broadly protective vaccine that works against a wide variety of variants, regardless of the number of mutations that develop.