Experts believe the COVID-19 vaccines will work on the new coronavirus variant, but they’re working to confirm that.

A coronavirus variant in the United Kingdom has caused alarm because of the possibility that it might spread more easily. But even if that turns out to be true, experts say the COVID-19 vaccines being rolled out will likely still work on the variant.

Dr. Anthony Fauci, the top U.S. infectious disease expert, said data coming from Britain indicates the vaccines still will block the virus. But the U.S. also will do tests to be sure.

Viruses often undergo small changes as they reproduce and move through a population. In fact, the slight modifications are how scientists track the spread of a virus from one place to another.

But if a virus mutates significantly enough, one worry is that current vaccines might no longer offer as much protection. And although that’s a possibility to watch for over time with the coronavirus, experts say they don’t believe it will be the case with the variant in the U.K.

“My expectation is, this will not be a problem,” said Moncef Slaoui, the chief science adviser for the U.S. government’s COVID-19 vaccine push.