US clears updated COVID boosters for new variants
The U.S. on Wednesday authorized its first update to COVID-19 vaccines, booster doses that target today's most common omicron strain. Shots could begin within days. The move by the Food and Drug Administration tweaks the recipe of shots made by Pfizer and rival Moderna that already have saved millions of lives. The hope is that the modified boosters will blunt yet another winter surge — and help tamp down the BA.5 omicron relative that continues to spread widely. Until now, COVID-19 vaccines have targeted the original coronavirus strain, even as wildly different mutants emerged. The new U.S. boosters are combination, or "bivalent," shots. They contain half that original vaccine recipe and half protection against the newest omicron versions, BA.4 and BA.5, that are considered the most contagious yet. The combination aims to increase cross-protection against multiple variants.
