Booster shots a possibility, maybe even annual ones

Scientists have long said that giving people a single course of a COVID-19 vaccine might not be sufficient in the long term — and that booster shots and even annual vaccinations might prove necessary.

In recent days, that proposition has begun to sound less hypothetical.

Vaccine makers are getting a jumpstart on possible new rounds of shots, although they sound more certain of the need for boosters than independent scientists have.

Pfizer CEO Albert Bourla said Thursday that a third dose of the company’s COVID-19 vaccine was

“likely” to be needed within a year of the initial twodose inoculation — followed by annual vaccinations.

Dr. David Kessler, who runs the Biden administration’s vaccine effort, told a House subcommittee on Thursday that the government is looking ahead. One factor at play is the spread of coronavirus variants and whether further vaccination could better target mutant strains.

Bourla said that “a likely scenario” is “a third dose between six and 12 months, and from there it would be an annual re-vaccination.”

Moderna said this week that it was at work on a booster for its vaccine, and Johnson & Johnson has said that its single-shot vaccine will probably need to be given annually.

Kessler emphasized the “strong efficacy” of the current vaccines, including against the variants, but said that the government was “taking steps to develop next generation of vaccines that are directed against these variants if in fact they can be more effective.”

He was one of a handful of top federal health officials at the House hearing who implored Americans to get vaccinated and sought to reassure the nation that all three federally authorized vaccines are safe. They said little about restarting Johnson & Johnson shots, which the Food and Drug Administration paused to examine a rare blood-clotting disorder.

Late Thursday, the Centers for Disease Control and Prevention said it had scheduled a new emergency hearing for April 23.