Dr. Anthony Fauci said that the U.S. is experiencing a decrease in COVID-19 cases, hospitalizations, and deaths, but must be ready “and flexible enough” to revert to requirements like indoor masking if a new variant arises that causes an increase in cases and hospitalizations.

Fauci, who has served as the director of the National Institute of Allergy and Infectious Diseases for more than three decades and is currently President Joe Biden’s chief medical adviser, made the comments during an interview for the BBC’s “Sunday Morning.”

The public health official has been a controversial and polarizing figure throughout the coronavirus pandemic. He claimed during the interview that “there’s no doubt” that restrictions prevented many infections, hospitalizations, and deaths. But he also acknowledged that there were negative repercussions.

“The bottom line is we’ll likely see an uptick in cases, as we’ve seen in the European countries, particularly the U.K.,” Fauci said, adding that he doesn’t think an “uptick” will evolve into a full-blown “surge.” The stealth Omicron subvariant has already become the dominant form of COVID worldwide, the World Health Organization (WHO) says, accounting for 86% of all COVID infections in the past month.

But in the U.S., stealth Omicron accounts only for roughly 30% of total new cases, which means the subvariant still has room for growth. But greater virulence does not necessarily mean stealth Omicron is more dangerous than Omicron. “When you look at the cases they do not appear to be any more severe [than Omicron] and they do not appear to evade immune responses either from vaccine or prior infection,” Fauci said.