Shot shows well on mutation

Study of Pfizer vaccine hints at effectiveness against variants

New research suggests that 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 U.S. 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 so 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.

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.

The study looked at one modification to the spike protein that both variants share, called N501Y, that is believed to be responsible for the easier transmission. Pfizer and researchers from the University of Texas Medical Branch in Galveston conducted lab tests to see if that mutation could thwart the vaccine.

They used blood samples from 20 people who received the vaccine, made by Pfizer and its German partner Biontech, during a large trial of the shots. Antibodies from those recipients fended off the virus in lab dishes, according to the study, posted late Thursday on an online site for researchers.

The findings have not yet been reviewed by outside experts, a key step for medical research.

But “it 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.

Dr. Anthony Fauci, the top U.S. infectious disease expert, said this week that the coronavirus variants don’t appear to block vaccine-induced antibodies but that testing to be sure of that is underway in the U.S. and elsewhere.