A new study suggests that the Covid-19 vaccine developed by Pfizer and BioNTech is effective against viruses carrying at least one of the key mutations found in two rapidly spreading coronavirus variants in the UK and South Africa. However, researchers caution that further work is needed to confirm the level of protection against the South African variant.
The study, which has not yet been peer-reviewed, involved blood samples from 20 individuals who had received the Pfizer/BioNTech vaccine. Scientists tested the ability of their antibodies to neutralise coronaviruses engineered to contain the N501Y mutation, an alteration in the spike protein that is a target for vaccines and may increase infectivity.
Results showed that vaccinated individuals had developed antibodies capable of neutralising viruses with the N501Y mutation. However, the study did not test the E484K mutation, another significant alteration found in the South African variant. Pfizer stated that it had tested 16 different mutations and none had a significant impact on vaccine efficacy, with further studies planned.
Experts have described the findings as reassuring but not definitive. Professor Stephen Evans of the London School of Hygiene & Tropical Medicine said: “This is good news, mainly because it is not bad news. Had the opposite result been found, that would have been bad and very concerning. But it does not yet give us total confidence that the Pfizer (or other) vaccines will definitely give protection.”
One limitation is that the researchers did not construct the virus with the full set of spike mutations found in either variant. Mutations may interact, potentially affecting the spike protein structure and vaccine effectiveness. Nonetheless, vaccines stimulate a diverse immune response, which may cope with some changes. Professor Deborah Dunn-Walters of the University of Surrey noted that the technology used to make the vaccines allows for rapid adjustments if necessary.
