Pfizer announced Thursday it will ask the Food and Drug Administration for emergency authorization of a third, or “booster” COVID-19 vaccine shot.
Two doses of most vaccines are vital to develop antibodies against all versions of the coronavirus. But antibodies naturally wane over time, so studies also are underway to tell if and when boosters might be needed.
On Thursday, Pfizer’s Dr. Mikael Dolsten told The Associated Press that early data from the company’s booster study suggests people’s antibody levels jump five- to 10-fold after a third dose compared to their second dose.
This news comes as one particular variant continues to surge around the world. The delta variant has become the dominant strain of COVID-19 in the United States.
Research from multiple countries shows the Pfizer shot and other widely used COVID-19 vaccines offer strong protection against the delta variant.
So why would a booster shot be necessary? Dr. Dolsten said the idea is a third shot would prevent antibodies from dropping low enough that the virus could cause a mild infection before the immune system kicks back in.
Even if Pfizer receives FDA approval, it wouldn’t automatically mean Americans get offered boosters. Public health authorities would have to decide if they’re really needed, especially since millions of Americans don’t even have either their first or second doses.
Hours after Pfizer’s announcement, U.S. health officials issued a statement saying fully vaccinated Americans don’t need a booster yet.
In a joint statement, the FDA and Centers for Disease Control and Prevention said they “are engaged in a science-based, rigorous process to consider whether or when a booster might be necessary.” That process will include data from the drug companies, “but does not rely on those data exclusively”. Any decision on booster shots would happen only when “the science demonstrates that they are needed,” the agencies said.
