Drug companies planning for vaccine booster shots

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 jump-start 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 COVID19 vaccine was “likely” to be needed within a year of the initial two-dose inoculation — followed by annual vaccinations.

“There are vaccines like polio where one dose is enough, and there are vaccines like flu that you need every year,” Bourla said. “The COVID virus looks more like the influenza virus than the polio virus.”

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

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 the government was “taking steps to develop the 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.

As of Thursday, more than 125 million people in the country had received at least one dose of a COVID19 vaccine, including about 78 million who have been fully vaccinated by Johnson & Johnson’s single-dose vaccine or the two-dose series made by Pfizer-BioNTech and Moderna.

In February, Pfizer and its partner, BioNTech, said they planned to test a third shot and update their original vaccine. The FDA has said that vaccine developers will not need to conduct lengthy trials for vaccines that have been adapted to protect against variants.

On Tuesday, Moderna said that its vaccine continued to provide strong protection in the United States against COVID-19 six months after it is given, and the company’s CEO, Stephane Bancel, told CNBC that he hoped to have booster shots ready by the fall.

ALLISON ZAUCHA/THE NEW YORK TIMES A nurse prepares doses of the Moderna vaccine in an LA medical office. Vaccine makers are girding for possible new rounds of shots.