Pfizer says tweaked COVID-19 shots boost omicron protection

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.

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.

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.

But many experts say 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.