WASHINGTON — U.S. regulators cleared second booster doses of COVID-19 vaccine from Moderna Inc. and the partnership of Pfizer Inc. and BioNTech SE for adults 50 and older, making millions more people eligible for the shots as concern grows about a potential new wave of infections.
Those who have received a first booster dose of the drugmakers’ shots at least four months earlier can now get another, the Food and Drug Administration said Tuesday. For most people, the second booster will be a fourth shot, while it will be the third for those who got initial single-shot immunizations from Johnson & Johnson.
While highly transmissible omicron has declined overall, the virus’s BA.2 strain has become dominant, leading to concerns about a resurgence and the need for additional safeguards. In many countries in Europe, cases remain at very high levels thanks to the even-more-transmissible subvariant. Booster doses are becoming an increasingly relied-upon tool in the fight against COVID especially as states and companies cut back safeguards such as masking and work from home.
“Current evidence suggests some waning of protection over time against serious outcomes from COVID-19 in older and immunocompromised individuals,” Peter Marks, who leads the FDA center that oversees vaccines, said in a statement. “Based on an analysis of emerging data, a second booster dose of either the Pfizer-BioNTech or Moderna COVID-19 vaccine could help increase protection levels for these higher-risk individuals.”
The Centers for Disease Control and Prevention chose not to convene a panel of outside advisers who make vaccine use recommendations, as it did with the first rounds of COVID shots. Instead, the agency gave its recommendation for the additional booster dose in a statement shortly after the FDA’s action.
“Boosters are safe, and people over the age of 50 can now get an additional booster four months after their prior dose to increase their protection further,” CDC head Rochelle Walensky said in a statement.
The agency landed on an age limit of 50 because there’s a significant enough group of people in that range who are at high risk, Marks said in a call with reporters. It would also help streamline vaccination programs, as the same age bracket is a cutoff point for immunizations against other respiratory viruses.
“We felt like we would capture the population that might most benefit from this fourth booster dose,” Marks said.
Much of the decision was based on analysis of data from Israel, which focused on the benefits of a second booster dose in those 60 years and over and people at high risk of severe outcomes of COVID-19, he said.
Meanwhile, the Biden administration is warning that funding is needed to continue fighting the virus. The U.S. lacks sufficient supplies to give everyone an additional booster dose of mRNA vaccine if regulators open up eligibility more widely, officials have said.
The FDA also authorized a second booster dose of Pfizer-BioNTech vaccine for certain immunocompromised people 12 and older, and Moderna’s vaccine for a similar population 18 and older. That additional shot can be administered at least four months after the receipt of a first authorized booster dose. People ages 12 and older with moderately or severely compromised immune systems were already able to get four shots, three of which counted as their primary series.
It’s not clear how significant the uptake will be for fourth-dose boosters, as cases are low in the U.S. and deaths are declining. By contrast, some countries like Israel that gave fourth doses to older people rolled them out at the height of the omicron wave.
This second booster may not be the last one. The virus is expected to continue to mutate, raising the likelihood that the vaccine will eventually need to be updated to fight new strains. Both Pfizer and Moderna are working on omicron-specific boosters, as well as shots that would combine the existing vaccine with an omicron-specific formulation. Data from those trials could start to arrive in the coming weeks.
With no clear consensus on future boosters, the FDA is planning a meeting of outside advisers on April 6 to assess broad questions of when additional COVID boosters should be given and when shots should be updated to address new variants.
Boosters of mRNA COVID vaccines like those from Moderna and Pfizer gave more protection against hospitalization than the viral-vector vaccine from Johnson & Johnson during omicron’s dominance, according to a separate study published by the CDC. Even people who received JNJ’s vaccine as their initial immunization were better protected by an mRNA booster, according to the study published in CDC’s Morbidity and Mortality Weekly Report.
