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The Pfizer-BioNTech Covid-19 vaccine may be less able to protect against infection with a South African variant of the virus that has a worrisome mutation, according to the results of a British study published Tuesday.
Preliminary data, which have not yet been peer-reviewed and involve a small number of patients, also suggest that a significant proportion of people over the age of 80 may not be sufficiently protected against new variants of the virus until they have received two dose of the vaccine. said the researchers leading the study.
“Of particular concern … is the appearance of the E484K mutation (found in the South African variant), which has so far only been seen in a relatively small number of individuals,” said Ravi Gupta, professor at the University’s Institute of Sciences. from Cambridge. Therapeutic Immunology and Infectious Diseases, who co-led the study.
“Our work suggests that the vaccine is likely to be less effective when it comes to this mutation.”
Britain and many other countries have started to implement the Pfizer-BioNTech vaccine to try to stop the spread of the pandemic disease.
While the highly effective vaccine is designed to be given in two doses three weeks apart, the UK government has chosen to extend that time frame up to 12 weeks to try to quickly reach as many people as possible with a first dose.
The study published Tuesday used blood samples from 26 people who had received their first dose of the Pfizer vaccine three weeks earlier to test whether the injection would protect against two variants of the SARS-CoV-2 virus: the UK variant, known as B1. .1.7., And the South African variant, which has the E484K mutation.
When analyzing the blood serum samples, all but seven of the participants had antibody levels high enough to neutralize the virus – that is, to protect against infection, the researchers said.
When the scientists added together all of the key mutations found in the B1.1.7 variant, however, they found that the efficacy of the vaccine was affected, with, on average, twice as high concentrations of antibodies required to neutralize the virus.
When the E484K mutation was added, even higher levels of antibodies were required for the virus to neutralize itself, averaging a 10-fold increase, the researchers said.
Dami Collier, who co-led the work, said the findings suggest that “a significant proportion of people over the age of 80 may not have developed protective neutralizing antibodies against infection three weeks after their first dose of the vaccine.”
Clinical trial data published last week on two other Covid-19 vaccines, from Novavax and Johnson & Johnson, also found that the South African coronavirus reduced their ability to protect against the disease.
