Pfizer said July 28 that a third dose of its COVID-19 shot "strongly boosts" the body's immune response against the delta variant of the coronavirus.
In slides the drugmaker posted ahead of an earnings call, Pfizer showed data that antibody levels against the delta variant were five times higher in people aged 18 to 55 after a third dose and 11 times higher in 65- to 85-year-olds.
Pfizer said July 8 that it plans to file for FDA authorization for a third dose of its vaccine. The same day, the CDC and FDA released a joint statement saying booster shots aren't currently necessary for those fully vaccinated against COVID-19. It's still unclear when and if booster shots will be necessary.
Experts told The Hill that antibody levels aren't the only measure of protection against the virus, as there are other parts of the immune system that are activated against the virus.