Scientists have long said that giving people a single course of a Covid-19 vaccine may not be enough in the long run, and that booster and even yearly vaccinations may prove necessary.
In the past few days this phrase has started to sound less hypothetical.
Vaccine manufacturers are given the go-ahead for possible new rounds of firing, although they are more certain of the need for boosters than independent scientists.
Pfizer chief executive Albert Bourla said Thursday that a third dose of the company’s Covid-19 vaccine will “likely” be needed within a year of the first two-dose inoculation – followed by annual vaccinations.
Dr. David Kessler, who leads the Biden government’s vaccination efforts, told a House subcommittee on Thursday that the government was also looking ahead. One factor at play is the spread of coronavirus variants and whether further vaccination might better target mutant strains.
Mr Bourla said that “a likely scenario” would be “a third dose somewhere between six and twelve months and from there an annual re-vaccination”. Moderna said this week that it was working on a booster for its vaccine, and Johnson & Johnson has said that its single-shot vaccine will likely need to be given annually.
Dr. Kessler stressed the “strong effectiveness” of the current vaccines, including against the variants, but said the government is “taking steps to develop next-generation vaccines that target these variants when they can actually be more effective”.
He was one of the few high-ranking federal health officials at the House hearing pleading with Americans to get vaccinated and attempting to reassure the nation that all three state-approved vaccines are safe. Little did they say about restarting Johnson & Johnson shots, which the Food and Drug Administration paused to investigate a rare blood clotting disorder.
Late on Thursday, the Centers for Disease Control and Prevention announced that a new emergency hearing was scheduled for April 23.
As of Thursday, more than 125 million people in the country had received at least one dose of a Covid-19 vaccine, including about 78 million who were fully vaccinated with Johnson & Johnson’s single-dose vaccine or the two-dose series from Pfizer-BioNTech and Moderna .
In February, Pfizer and its partner BioNTech announced that they were planning to test a third shot and update their original vaccine. The FDA has stated that vaccine developers do not need to conduct lengthy studies for vaccines that have been adapted to protect against variants.
On Tuesday, Moderna announced that the vaccine will continue to offer strong protection against Covid-19 in the US six months after its administration, and the company’s executive director, Stéphane Bancel, told CNBC that he hopes to have booster vaccinations by the fall .