Pfizer Inc. and partner BioNTech SE have asked U.S. health regulators to authorize a second booster dose of their Covid-19 vaccine for people 65 years and older.
The companies said Tuesday that they had filed the application. The Food and Drug Administration is expected to make a decision in time for the Biden administration to begin a potential fall vaccine campaign.
The FDA has been reviewing data and looking at potentially authorizing a fourth dose of the shot for use in the fall, The Wall Street Journal reported last month.
Health authorities have cleared booster doses for children as young as 12 years of age, at least five months after they finished their first round of vaccination.
Health authorities have been urging people to get a booster dose, as studies have shown that Covid-19 vaccines’ protection declines over time. Research has shown the booster can strengthen immune systems that have weakened months after initial vaccination.
The Centers for Disease Control and Prevention already recommends fourth doses for people whose immune systems are compromised.
Countries including Israel, Germany, Sweden and the U.K. have begun or announced plans for second booster doses.
Researchers are divided on whether additional booster shots are needed, when they should be given and which individuals should receive them.
There is limited data showing how well a fourth dose works, and it is somewhat mixed.
In January, Israel’s health ministry published an initial study saying a fourth shot provided threefold protection against serious illness and twofold protection against infection compared with people who were four months after their third shot. Other Israeli researchers who did a separate study cast doubt on whether a fourth shot added effective protection against the Omicron variant.
Pfizer said its submission is based on a pair of real-world studies from Israel that showed an additional dose of vaccine increased immunogenicity and lowered the rates of infections and severe disease.
Pfizer is still studying how much protection a fourth dose of the current vaccine may provide, part of a broader clinical trial started in January looking at a vaccine tailored to target the Omicron variant.