Pfizer and Moderna are testing their coronavirus vaccines to see if they work against the new mutated version of the virus that’s recently been found in the United Kingdom and other countries, according to company statements.

“Based on the data to date, we expect that the Moderna vaccine-induced immunity would be protective against the variants recently described in the UK,” Moderna said in a statement.

“We will be performing additional tests in the coming weeks to confirm this expectation.”

Pfizer said it is now “generating data” on how well blood samples from people immunized with its vaccine “may be able to neutralize the new strain from the UK.” 

Pfizer and Moderna make the only two coronavirus vaccines that have been authorized by the US Food and Drug Administration. 

The novel coronavirus has mutated before, and both companies say they’ve found that their vaccines worked against other variations of the virus.

Some researchers who are examining the genome of the UK variant told CNN they have concerns that this variant’s mutations might possibly somewhat diminish the effectiveness of the vaccine. 

“You could imagine some modest hit in vaccine efficacy, which wouldn’t be good, but I don’t think it would break the vaccine,” said Trevor Bedford, an associate professor in the vaccine and infectious disease division of the Fred Hutchinson Cancer Research Center.