Pfizer says changing its COVID-19 vaccine to better target the omicron variant is safe and effective.
The update, in a statement issued Saturday, comes just days before regulators determine if Americans should receive another round of booster shots beginning this fall.
The most widely used vaccines currently in circulation mostly target the original, more dangerous but less viral, coronavirus strain. Their effectiveness against any infection dropped significantly, however, when the super-contagious omicron mutant emerged.
The Food and Drug Administration will consider this week if it should order a formula change for the vaccines made by both Pfizer
and its partner BioNTech
as well as their rival Moderna
in hopes that modified boosters could better protect against another COVID-19 surge expected this fall and winter. Other major countries are mulling the same shift.
Read: Sanofi, GSK say next-generation COVID-19 booster has 72% efficacy against omicron
“Based on these data, we believe we have two very strong omicron-adapted candidates that elicit a substantially higher immune response against omicron than we’ve seen to date,” said Pfizer CEO Albert Bourla.
The statement said the companies are ready to “rapidly adapt” the updated vaccines to target newer versions of the virus if needed.
Pfizer says it studied two different ways of updating their shots — targeting just omicron, or a combination booster that adds omicron protection to the original vaccine. The company and its partner also tested whether to keep the current recommended dosage of 30 micrograms or double its 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 showed a significant increase in omicron-fighting antibodies.
Several experts have said combination shots may be the best approach because they would retain the proven benefits of the original COVID-19 vaccine while adding new protection against omicron.
Pfizer said a month after people received its combo shot, they had a 9- to 11-fold increase in omicron-fighting antibodies. That’s more than 1.5 times better than another dose of the original vaccine, the Associated Press reported.
Moderna recently announced similar results from tests of its combination shot, or what scientists call a “bivalent” vaccine.
The Associated Press contributed.