“In the absence of a dramatically different variant, we likely are moving towards a path with a vaccination cadence similar to that of the annual influenza vaccine,” Dr. Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases and physician to the president, said at a news conference heralding the approval and distribution of new Omicron boosters.

Ideally, updates to the COVID-19 shot will be made each year to match circulating strains, as is done with the flu vaccine, he added.

But some experts disagree with Fauci’s prediction, warning that typical COVID vaccine immunity only lasts four to six months—and that the virus is still evolving.

“I don’t see any evidence for how an annual COVID shot will provide durable protection … without better vaccines,” Dr. Eric Topol, a professor of molecular medicine at Scripps Research and founder and director of the Scripps Research Translational Institute, said this week via tweet.

“To give a false impression of year-long protection ([against] severe disease and death) with the data in hand is not acceptable,” he later added.

Even the flu vaccine doesn’t offer year-long protection, Dr. Lee Altenberg, a theoretical biologist and professor at the University of Hawaiʻi at Mānoa, pointed out via tweet, citing a 2019 article from Clinical Infectious Diseases that says the flu shot’s protection lasts only 90 to 160 days at most.

Such a length of protection may generally work with a seasonal virus like the flu. But COVID isn’t seasonal, Altenberg and other experts say, with surges primarily driven by new variants of concern.

“This ‘annual COVID shot’ is more urgency-of-normal denial of the pandemic’s reality—an attempt to pretend it is like the flu—to gaslight people [that] it’s the flu,” Altenberg tweeted.

The vaccine strategy should not be to “chase variants,” but to develop a broad, robust vaccine that provides “strong immunity to as many variants as possible,” Dr. Andrew Pekosz, a virologist and professor at the Department of Molecular Microbiology and Immunology at the Johns Hopkins Bloomberg School of Public Health, said Thursday.

Case in point: New COVID variants BA.4.6 and BA.2.75 are able to partially escape vaccine-induced immunity, though they “should be recognized” by new Omicron boosters, he said.

U.S. ‘caught up with the virus,’ but behind other nations

Nasal vaccines, in addition to vaccines that tackle all COVID variants or even all coronaviruses, are the way forward, Topol and other experts contend. 

But so far none are available in the U.S.—belying the statement made this week by White House COVID czar Dr. Ashish Jha that science has “caught up with the virus.”

Earlier this week China approved CanSino Biologics’ inhaled COVID vaccine for use as a booster. Clinical trial data showed that it was more effective, as a booster, at preventing infections from Omicron and other variants than the injectable vaccine made by Chinese firm Sinovac.

It’s the first inhaled vaccine for any disease, Pierre Morgon, an executive vice president at its manufacturer, CanSino Biologics, recently told Fortune. While a nasal spray vaccine, Flu Mist, exists for the flu, its contents are absorbed through tissue inside one’s nose and are not intended to be inhaled.

And India this week approved its first nasal spray vaccine, with its manufacturer, Bharat Biotech, calling it a “global game changer.” (Russia and Iran also claim to have approved and widely distributed nasal spray vaccines.)

There are “multiple ways” to achieve a vaccine that gives true year-long protection against COVID, “and the U.S. is not actively, aggressively pursuing any of them,” Topol said on Twitter this week.

“Boosting our way out is untenable.”