Pfizer to begin testing booster shot targeting variants

From USAToday: "Pfizer-BioNTech will begin testing a booster shot to combat COVID-19 variants, the companies announced Thursday. The announcement came one day after new research published in the New England Journal of Medicine confirmed that two doses of the Pfizer-BioNTech vaccine cut symptomatic COVID-19 cases across all age groups by 94%.

Now the two-company collaboration has asked 144 volunteers who participated in the earliest phase of its clinical vaccine trials last year to volunteer again to receive the booster, a third shot of the same vaccine designed to see whether it will help them fight off new, more infectious variants that have been circulating in recent months. It’s not yet clear whether a new vaccine or booster will be needed to address the known variants, but companies want to be prepared if studies show a new vaccine is needed."