The Covid-19 vaccine developed by BioNTech and Pfizer is likely to be effective against a rapidly spreading strain of the virus that was first discovered in the UK, a laboratory-based study by the companies has shown. The variant, known as B.1.1.7, has a high number of mutations, which has led to concerns that could bypass the immune defenses built up by vaccines being rolled out worldwide, a large proportion of which have been made by BioNTech and Pfizer.
However, researchers at BioNTech’s headquarters in Mainz found that a test-tube version of the virus-carrying all the new strain’s mutations was neutralized by antibodies in the blood of 16 patients who had received the vaccine in previous trials, half of whom were over 55 years old. In a paper that has yet to be peer-reviewed, the companies said there was “no biologically significant difference in neutralization activity” between the results of the lab tests on surrogate versions of the original strain of the coronavirus, sequenced in China last January, and the new variant.
But the authors warned that the “ongoing evolution of Sars-Cov-2 necessitated continuous monitoring of the significance of changes for maintained protection by currently authorised vaccines”. The test is the first of its kind to be completed by a major vaccine maker, as companies rush to check their jabs hold up against the new variant.
Pfizer and researchers at the University of Texas had already checked it against one of the most worrying changes in the new variant that emerged in the UK and South Africa, in a lab study published earlier this month. Moderna and Oxford/AstraZeneca, which are both in the process of testing their vaccines, have previously said they expected their jabs to protect against B.1.1.7.
But a group of scientists in South Africa have warned that vaccines could be less effective against the 501Y.V2 strain that is driving a second wave of Covid-19 infections there, because it has an extra mutation in a key part of the spike protein that the virus uses to enter human cells.
A study of serum from 44 South Africans, who had previously been infected with earlier versions of the Sars CoV-2 virus, found that 90 per cent were not fully protected against the new variant — and the antibodies in about half the sample were not at all protective. Salim Abdool Karim, chief adviser to the South African government on Covid-19, said: “Vaccine antibodies are different and may or may not be impacted. We have no empirical evidence yet on whether vaccines are effective against the 501Y.V2 variant. Studies are under way.”
Even if vaccines still work well against the current variants, vaccine makers and regulators are starting to prepare for the virus to mutate further. If vaccines become significantly less effective, the companies will need to adapt their formulations and manufacture new batches.
BioNTech’s researchers said that unlike longstanding flu jabs, the point at which the shot would have to be tweaked to fight any new strain “has not been established for Covid-19 vaccines”. Previously, BioNTech has said that it could tweak its vaccine to tackle a new strain in roughly six weeks. But it would be up to regulators to decide what evidence they will require to be satisfied that a modified product is safe and effective, and whether they will necessitate further clinical trials.
Source: FT
