“It will depend on who you are,” Fauci told the Financial Times, “but if you are a normal, healthy 30-year-old person with no underlying conditions, you might need a booster only every four or five years.” 

Fauci has been noting for months that it was unclear if annual shots would be needed, saying in December that “we don’t know what’s going to be required.” But Fauci’s statement Wednesday is the clearest expression yet of his doubt that annual COVID boosters will be necessary—and goes against other scientists who have suggested vaccines would be needed annually as COVID-19 becomes endemic.

Here’s where Fauci stands compared to other public health experts—and the pharma industry.

The annual jab chorus

England’s National Health Service chief executive Amanda Pritchard said in November that the health service was already preparing to offer an annual COVID-19 booster vaccine program if one is required, and has ordered 114 million new doses of Pfizer and Moderna shots to be delivered in 2022 and 2023. Similarly, Germany already offers a fourth booster vaccine to vulnerable people, and Ulrich Weigeldt, the head of Germany’s general practitioners association, told the newspaper Bild in December that he expected boosters to mirror the yearly flu vaccine.

Big pharmaceuticals are also (perhaps not surprisingly) on board for repeated jabs. Pfizer chief executive Albert Bourla said in a January interview with Israel’s N12 News, “What I’m hoping [is] that we will have a vaccine that you will have to do once a year,” adding, “once a year—it is easier to convince people to do it. It is easier for people to remember.”

And speaking at the World Economic Forum in January, Moderna CEO Stéphane Bancel said his company was planning to offer a seasonal booster shot by fall 2023 that would offer protection against COVID-19 as well as other respiratory illnesses like the flu and respiratory syncytial virus (RSV). 

“Our goal is to be able to have a single annual booster so that we don’t have compliance issues where people don’t want to get two to three shots a winter, but they get one dose where they get a booster for corona, a booster for flu and RSV,” Bancel said.

Fourth dose doubts

Evidence supporting repeated jabs has so far been mixed at best.

While third shot boosters are now ubiquitous in countries in the Global North, they rose to prominence only after Omicron swept through the world, proving two vaccine doses didn’t offer enough protection against severe disease.

But to get an accurate measurement of how continuous boosters do, scientists point to Israel, which has already rolled out a fourth dose to all adults.

A preliminary study published by Israel’s Sheba Medical Center in January found that a fourth shot was “not good enough” to fend off Omicron; however, it did increase antibodies to higher levels than the third shot. “The vaccine, which was very effective against the previous strains, is less effective against the Omicron strain,” said professor Gili Regev-Yochay, a lead researcher in the experiment.

The findings from Israel are aligned with recommendations made by the World Health Organization, which warned that repeating booster doses of the original COVID vaccines was not a viable strategy against emerging variants. The WHO Technical Advisory Group on COVID-19 Vaccine Composition said in a January statement that repeat boosters were “unlikely to be appropriate or sustainable.” The group has not made a statement whether a new, variant-specific vaccine would help any more or less.

Europe’s drug regulator warned in January excessive COVID boosters could lead to “problems with immune response,” joining WHO in the pushback.

So…every one, two, or five years?

Some experts say there is more data needed to see how often booster shots will be necessary. “We’re learning as we go along. None of us would be surprised if there would be a need for boosters at some interval. Would it be a year, two years, five years? We don’t know,” William Schaffner, an infectious disease expert at Vanderbilt University in Tennessee, said in Healthline in November.

Others, like Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, are even less convinced that constant jabs will be the future. Hotez said in November in the Journal of the American Medical Association that annual doses were unlikely to be necessary. “I think there’s a high probability that it could be three [doses] and done.”