Study finds Pfizer effective against mutant strains

New research suggests Pfizer’s COVID-19 vaccine can protect against a mutation found in the two more-contagious variants of the coronavirus that have erupted in Britain and South Africa.

The study was preliminary and did not look at the two other major vaccines being used in the West — Moderna’s and AstraZeneca’s. But it was reassuring, given questions of whether the virus could mutate to defeat the shots on which the world has pinned its hopes.

“There’s no reason to think the vaccines won’t work just as well on these strains,” said Dr Frederic Bushman of the University of Pennsylvania, who tracks how the virus mutates.

The mutated version circulating in Britain has also been detected in the US and numerous other countries. That and the variant seen in South Africa are causing global concern because they appear to spread more easily, although how much more isn’t yet known.

Bushman, who wasn’t involved with the Pfizer study, cautioned that it tested just one vaccine against one worrisome mutation. But the Moderna and AstraZeneca vaccines are undergoing similar testing, and he said he expects similar findings.

That’s because all the vaccines so far are prompting recipients’ bodies to make antibodies against multiple spots on the spike protein that coats the virus.

“A mutation will change one little place, but it’s not going to disrupt binding to all of them,” Bushman explained.

While scientists did not expect that a single mutation would completely upend efforts to stop the pandemic, it is still an important area of study because the coronavirus, like all viruses, constantly evolves.

This study marks just the beginning of continual monitoring to make sure that all the vaccines being rolled out around the world continue to work.

The study looked at one modification to the spike protein that both variants share, called N501Y, that is believed responsible for the easier transmission.

Scientists conducted laboratory tests to see if that mutation could thwart the vaccine. They used blood samples from 20 people who received the Pfizer/ BioNTech vaccine during a large trial.

Antibodies from those recipients fended off the virus in lab dishes, according to the study.

“I was a very reassuring finding that at least this mutation, which was one of the ones people are most concerned about, does not seem to be a problem” for the vaccine, said Pfizer chief scientific officer Dr Philip Dormitzer.