White House chief medical adviser Dr. Anthony Fauci cautioned Tuesday that "we should not be surprised" if a new COVID-19 variant emerges in the winter. 

Speaking during an event with the USC Annenberg Center for Health Journalism, Fauci said that while pandemic trends like hospitalizations were down nationwide, challenges still lie ahead.

"We should anticipate that we very well may get another variant that would emerge that would elude the immune response that we've gotten from infection and/or from vaccination," Fauci said, noting that there's always the risk of an uptick of respiratory diseases during the winter months. 

Last winter, the omicron variant led to a surge in cases, and multiple sublineages have spread since then.

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Fauci points finger

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, responds to questions by Senator Rand Paul during the Senate Health, Education, Labor, and Pensions Committee hearing on Capitol Hill in Washington, DC on July 20, 2021. (Photo by J. SCOTT APPLEWHITE/POOL/AFP via Getty Images)

"Remember, we were going in the right direction in the summer of 2021 and along came delta. Then, in the winter – November, December of 2021 – along came omicron. And, since then, we've had multiple sublineages of omicron," he said.

The White House and health officials are encouraging eligible Americans to get an updated omicron-specific booster shot of the coronavirus vaccine.

Anthony Fauci

Dr. Anthony Fauci, White House chief medical adviser, participates in the White House COVID-19 Response Team's regular call with the National Governors Association in the South Court Auditorium in the Eisenhower Executive Office Building on the White House Campus, Monday, Dec. 27, 2021, in Washington.  (AP Photo/Carolyn Kaster)

Fauci pointed out that the vaccine was directed at the major-circulating variant.

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Anthony Fauci at the White House with hand in the air

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, speaks during the daily briefing at the White House in Washington, Wednesday, Dec. 1, 2021.  (AP Photo/Susan Walsh)

Data from the Centers for Disease Control and Prevention shows BA.5 is the prevalent variant, making up more than 81% of cases.

According to the Johns Hopkins Coronavirus Resource Center, COVID-19 has killed more than a million people in the U.S. and infected over 96 million.

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In the past day, there have been more than 42,000 new cases and 542 new deaths.