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January 11, 2021

Pfizer's COVID-19 vaccine effective against U.K. variant, study suggests

Both Pfizer and Moderna are testing their vaccines against various coronavirus mutations

Pfizer's COVID-19 vaccine is still effective against a key mutation found in the United Kingdom and South Africa variants of the coronavirus, preliminary research suggests. 

The mutation, called N501Y, is a slight tweak to the spike protein that the virus uses to enter cells. This mutation is thought to make the virus more contagious, infectious disease experts say.

One study estimates the mutation makes the virus 56% more contagious, but it doesn't appear to cause more severe illness, according to available data. 

The new research comes as coronavirus variants raise alarms across the world and the vaccine rollouts remain in early stages.

Pfizer, in a collaboration with researchers from the University of Texas Medical Branch in Galveston, analyzed blood samples from 20 vaccine recipients. The antibodies induced by the Pfizer-BioNTech vaccine were able to successfully defend against 15 possible mutations of the virus in laboratory dishes.

The variant first found in South Africa carries an additional mutation, E484K. That mutation was not among those tested, but the Pfizer's chief scientific officer, Dr. Philip Dormitzer, told the Associated Press that researchers will be testing for it next.

The findings haven't been peer-reviewed yet, but are available on the preprint server bioRxiv. Moderna also is conducting similar testing for its COVID-19 vaccine.

Viruses naturally mutate as they spread from person to person. Most alterations are minor, but the variant responsible for the U.K.'s lockdown has public health officials worried.

Vaccines are designed to recognize several parts of the spike protein covering the virus, so one mutation typically isn't enough to impact vaccine coverage, although testing is always necessary to confirm this.

If a virus changes in significant ways that affect its behavior, vaccines need to be adjusted to offer optimum protection. This is why people need a new flu shot every year.

British researchers say the variant, first identified in the U.K., appears still to be vulnerable to the vaccines. The latest data from Pfizer offers more reassurance at a time when the variant is also being discovered in the U.S., including Pennsylvania.

A Pennsylvania resident tested for the U.K. variant last week after a known international exposure. The person experienced mild symptoms that subsided while self-isolating.

Dormitzer said that continuous monitoring of coronavirus mutations will be necessary to determine if they weaken the effectiveness of the vaccines.

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