Why COVID boosters weren’t tweaked to better match variants

Associated Press

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.

The simple answer: The FDA last month OK’d extra doses of Pfizer’s original recipe after studies showed it still works well enough against delta -- and those doses could be rolled out right away. Now the FDA is weighing evidence for boosters of the original Moderna and Johnson & Johnson vaccines.

“It’s less churn and burn on the manufacturing” to only switch formulas when it’s really necessary, said FDA vaccine chief Dr. Peter Marks.

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Monday, October 18, 2021 - 11:35am

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