Fauci says it's 'tough to tell' if there will be a need for annual COVID-19 booster, but if there is, 'then we'll just have to deal with it'

• Dr. Fauci can't say for sure whether people will need a yearly vaccine booster shot amid the COVID Omicron variant.
• Fauci has said that boosters provide the optimal protection against the worst effects of COVID. 
• Cases of the COVID Omicron variant have been detected in at least 25 states and is on the rise.

Dr. Anthony Fauci can't say whether people will need annual COVID-19 COVID-19 boosters, a question being posed by many as new variants of the coronavirus, like Omicron, arise.

"It's tough to tell," Fauci, the nation's leading infectious disease expert, said during an interview Sunday on ABC News "This Week" with George Stephanopoulos.

Fauci, the director of the National Institute of Allergy and Infectious Diseases, said that besides an increased level of protection against the coronavirus, a booster could increase the durability of the immune system's protection, which won't be measurable for a "period of months."

"If it becomes necessary to get yet another boost, then we'll just have to deal with it when that occurs," Fauci added.

"But I'm hoping, from an immunological standpoint, that that third shot of an mRNA and the second shot of a J&J will give a much greater durability of protection than just the six months or so that we're seeing right now," he said, referring to vaccines made by Pfizer, Moderna and Johnson & Johnson, respectively.

Conversations about the booster shots have become more prevalent as the US has seen COVID-19 cases climb, and concern grow about the more contagious Omicron variant. Since November, the Omicron variant has been detected in at least 25 states, most recently in Florida and Texas.

The majority of Omicron cases in the US have reported mild symptoms so far, but the variant may be more resistant to basic COVID vaccine protections as most cases of Omicron in the US appear in fully vaccinated individuals.

A booster following a primary vaccination has drastically decreased the severity of  illness or likelihood of death, Fauci said. A Pfizer-BioNTech study also found that a booster shot could help restore the immune system's protection against COVID-19 to original levels. The scientific community is still studying the long-term protections of boosters.

"We have the tools to protect ourselves, and that's the thing we keep saying over and over again," Fauci said, noting 100 million Americans are now eligible for boosters. "On that framework alone, just vaccination, we can go a long way to getting us through this cold winter season."