Pfizer Says Its Vaccine Works Against Key Mutation in Contagious Variants

Pfizer and BioNTech announced on Friday that their Covid vaccine is effective against one of the mutations present in the new contagious variants identified in Britain and South Africa.

Independent experts said the findings were good news, but cautioned that each of those coronavirus variants has several other potentially dangerous mutations that have not yet been investigated. So it’s possible that one of those mutations affects how well the vaccine works.

“It’s the first step in the right direction,” said Dr. John Brooks, the chief medical officer for the Centers for Disease Control Covid-19 emergency response. “I’m hoping that the additional work that comes out in the future will fall in line with that finding.”

The new variant, known as B.1.1.7, first raised concern in December, when British researchers realized that it was rapidly becoming more common among people with Covid-19. Since then, it has turned up in 45 countries.

Subsequent research has confirmed that it has the capacity to spread more easily from person to person. On Friday, Public Health England released a new study of B.1.1.7 in which researchers estimated that the variant is 30 to 50 percent more transmissible than other forms of the virus.

The viral lineage leading to B.1.1.7 has accumulated 23 mutations. Of particular concern to scientists are eight mutations that affect the gene for a protein called spike on the surface of coronaviruses. That’s because the viruses use the spike protein to grab onto human cells. It’s possible that one or more of them help B.1.1.7 invade cells more successfully.

One of these mutations, known as N501Y, is particularly worrisome. Experiments have demonstrated that it enables the virus to bind to cells more tightly. And it has also arisen in other lineages of the coronavirus, including a variant identified in South Africa in December. That variant, called B.1.351, rapidly spread through the country, and has spread to a dozen other countries so far.

In the new study, which was posted online Thursday and has not yet gone through formal scientific review, researchers at the University of Texas Medical Branch ran an experiment to see if the Pfizer-BioNTech vaccine worked against viruses with the N501Y mutation. They found that in cells in the lab, the mutant virus could not infect human cells mixed with antibodies from vaccinated people. The antibodies latched onto the coronaviruses and blocked them from grabbing into cells. Despite the N501Y mutation, the experiment showed, the vaccine-generated antibodies were still able to latch onto the viruses.

“This indicates that the key N501Y mutation, which is found in the emerging U.K and South Africa variants, does not create resistance to the Pfizer-BioNTech vaccine induced immune responses,” the companies said in a news release.