Pfizer announced Saturday that tweaking its COVID-19 vaccine to better target the omicron variant is safe and works — just days before regulators debate whether to offer Americans updated booster shots this fall.
The vaccines currently used in the U.S. still offer strong protection against severe COVID-19-19 disease and death — especially if people have gotten a booster dose. But those vaccines target the original coronavirus strain and their effectiveness against any infection dropped markedly when the super-contagious omicron mutant emerged.
Now with omicron’s even more transmissible relatives spreading widely, the Food and Drug Administration is considering ordering a recipe change for the vaccines made by both Pfizer and rival Moderna in hopes that modified boosters could better protect against another COVID-19 surge expected this fall and winter.
Pfizer and its partner BioNTech studied two different ways of updating their shots — targeting just omicron, or a combination booster that adds omicron protection to the original vaccine. They also tested whether to keep today’s standard dosage — 30 micrograms — or to double the shots’ strength.
In a study of more than 1,200 middle-aged and older adults who’d already had three vaccine doses, Pfizer said both booster approaches spurred a substantial jump in omicron-fighting antibodies.
“Based on these data, we believe we have two very strong omicron-adapted candidates,” Pfizer CEO Albert Bourla said in a statement.