A flurry of European travel restrictions announced Sunday over worries about a fast-spreading new variant of the coronavirus have spurred curiosity and concern that the mutation could infect Americans. After officials in the United Kingdom said Saturday that the variant first identified there was spreading 70 percent faster than others, Google searches about the mutation have spiked. But American public health experts and federal officials say that although it appears that the variant may be more contagious, it is not any more dangerous than others already detected in the United States.

“I don’t think there should be any reason for alarm right now,” Adm. Brett Giroir, who has been in charge of testing, told George Stephanopoulos on ABC’s “This Week.”

Variations to the virus are nothing new, and experts say the novel coronavirus does not mutate as much as influenza, meaning it is less likely that a vaccine would need to be developed every year to keep up with the new strains. Still, much about this variant remains unknown, such as whether it is a new strain — a functionally different version of the virus.

“The take-home message for right now is that we need to get more information,” said Krutika Kuppalli, an infectious-diseases specialist at the Medical University of South Carolina. “In the meantime, we all need to really double down on our public health measures — wearing masks, remaining physically distanced, avoiding crowds of people.”

Where has the variant been detected?

In September, U.K. researchers discovered the variant’s prevalence when they collected samples from infected people in southeastern England. It seemed to spread quickly.

“This lineage came up quite rapidly,” Nick Loman, one of the researchers and a professor of microbial genomics at the University of Birmingham, told The Washington Post.

Since then, Australia, Denmark and the Netherlands have identified cases of the variant in their countries, the World Health Organization told the BBC. On Sunday, Italian officials announced that a patient returning from Britain “in the last few days” was in isolation after scientists detected the mutation.

Is the variant already in the United States?

The virus has not been detected in the United States, but officials are watching for developments in Britain, Giroir told Stephanopoulos. Although guidance from federal agencies discourages traveling to Britain, the United States has not banned travel from there.

“I really don’t believe we need to do that yet,” Giroir said.

But New York Gov. Andrew M. Cuomo (D) pointed out Sunday that it would take only one flight to the United States to spread the mutation, urging federal officials to restrict travel.

“Right now, this variant in the U.K. is getting on a plane and flying to JFK,” Cuomo said on a conference call with reporters.

However, Kuppalli warned that little is known about the effectiveness of a ban, referring to instances in which people rushed to airports and congregated in long lines trying to travel before restrictions were put into effect earlier in the pandemic.