Why COVID boosters weren't tweaked to better match variants

COVID-19 booster shots are an extra dose of the original vaccine, and some experts wonder why they weren't updated to better match the delta variant

More COVID-19 booster shots may be on the way -- but when it’s your turn, you’ll get an extra dose of the original vaccine, not one updated to better match the extra-contagious delta variant.

And that has some experts wondering if the booster campaign is a bit of a missed opportunity to target delta and its likely descendants.

“Don’t we want to match the new strains that are most likely to circulate as closely as possible?” Dr. Cody Meissner of Tufts Medical Center, an adviser to the Food and Drug Administration, challenged Pfizer scientists recently.

“I don't quite understand why this is not delta because that's what we're facing right now,” fellow adviser Dr. Patrick Moore of the University of Pittsburgh said last week as government experts debated whether it's time for Moderna boosters. He wondered if such a switch would be particularly useful to block mild infection.