The United States is unlikely to impose further restrictions amid the anticipated arrival of the Omicron COVID-19 variant, the nation’s top infectious disease official said on Monday after a travel ban on some southern African nations began.

Dr. Anthony Fauci, who was to brief U.S. President Joe Biden later on Monday, said that while officials were bracing for the first confirmed U.S. case of the variant, vaccines remained a top tool to blunt its impact.

Hours earlier, a U.S. ban blocked most travelers from eight southern African countries from entering the country in an effort to slow transmission and give experts more time to assess Omicron, including its severity, transmissibility and impact on vaccines.

Asked if other curbs were imminent, Fauci told ABC News’ “Good Morning America” program: “I don’t think so at all.”

Much of the United States shut down in early 2020 at the beginning of the pandemic, and other measures such as face masks and vaccine mandates have become politically contentious even as health experts tout their effectiveness.

Biden is scheduled to deliver public remarks on his administration’s response to the novel coronavirus at 11:45 a.m. ET (1645 GMT) following his meeting with Fauci and the rest of his COVID-19 team.

Fauci and other U.S. health officials on Monday said they were anticipating the variant’s arrival and urged more Americans to get vaccinated and receive booster shots if eligible.

“Obviously, we’re on high alert,” Fauci, who also serves as Biden’s chief medical adviser, told ABC News. “It’s inevitable that, sooner or later, it’s going to spread widely.”

National Institutes of Health Director Dr. Francis Collins said that so far, vaccines have appeared to work against other COVID-19 variants and that officials hope that would be the case with Omicron as vaccine makers rush to conduct tests.

“There’s reason to be pretty optimistic here,” Collins said in an interview on MSNBC.

Photo: Dr. Anthony Fauci