Pfizer vaccine may protect against new mutations of coronavirus

New Delhi: Scientists have found evidence that the COVID-19 vaccine co-developed by the US pharmaceutical giant Pfizer and German biotechnology company BioNTech may protect against the novel coronavirus variant which originated in the UK and has been reported in several parts of the world, including India.

In a yet-to-be peer-reviewed research, scientists from the University of Texas Medical Branch in the US, tested the ability of blood serum from 20 individuals immunised with the Pfizer-BioNTech vaccine to neutralise coronavirus engineered to carry the new mutations.

"Rapidly spreading variants of SARS-CoV-2 that have arisen in the UK and South Africa share the spike N501Y substitution, which is of particular concern because it is located in the viral receptor binding site for cell entry and increases binding to the receptor," the scientists noted in the study.

In these mutant forms, the molecule asparagine in the 501st position of the viral spike protein's amino acid sequence, is replaced by another amino acid tyrosine which is noted as Y.

"These rapidly spreading variants share the spike N501Y substitution. This mutation is of particular concern because it is located in the viral receptor binding site for cell entry, increases binding to the receptor, and enables the virus to expand its host range," the study noted.

When the researchers tested the sera of 20 participants who received the Pfizer-BioNTech vaccine they found that it could act against the engineered coronavirus variants.

"The new data provides important confirmation that the multiple antibodies generated against the spike protein (S) by vaccination remain able to inhibit cell entry by variant viruses," virologist Ian Jones from the University of Reading in the UK, who was unrelated to the study, said in a statement.

"This is because while some antibodies may not bind to S proteins with, for example the N501Y mutation, most antibodies still do, and this is sufficient to maintain protection," Jones added.

Gary McLean, Professor in Molecular Immunology from the London Metropolitan University in the UK said while the findings offer "good news", the study "did not construct SARS-CoV-2 with the full set of spike mutations in the UK variant and therefore further conclusions cannot be made fully at this stage."

While the current research, assessed the ability of the Pfizer-BioNTech vaccine to counter the strains carrying the N501Y mutation, virologist Lawrence Young from the University of Warwick in the UK said there are also other changes observed in these strains which might affect infectivity "and these have not been examined."

"This is particularly a concern with the South African variant which has accumulated two additional changes in the key receptor-binding domain of the spike gene," Young said.

"These changes are very likely to influence the infectiousness of this South African variant and may also impact its ability to be blocked by antibodies," he added.

Owing to the ongoing evolution of the coronavirus, scientists have called for the continuous monitoring of the significance of changes in the virus for vaccine coverage.

"This surveillance is accompanied by preparations for the possibility that a future mutation in SARS-CoV-2 might necessitate a vaccine strain change," the scientists wrote in the study.