Pfizer: COVID-19 Booster Shot Strongly Protects Against Delta Variant

The company says a booster shot would increase protection at least 5-fold for most adults and it's even more effective for seniors.

Pfizer says new data suggests a third dose of its COVID vaccine can strongly increase protection against the delta variant. The company disclosed that ongoing testing of a booster shot, given six months after the second vaccine dose, showed it raised antibody levels against the more-transmissible Delta variant to 11 times higher in older people and five times higher in younger people, compared to levels after the two-dose regimen. The data has not been peer-reviewed and U.S. health officials have said, at this point, the science doesn't show a need for a booster shot.