On Feb. 18, 2021, Pfizer and BioNTech announced that the first participants hadbeen dosed in a global Phase 2/3 study to further evaluate the safety, tolerability, and immunogenicity of the Pfizer-BioNTech COVID-19 vaccine(BNT162b2) in preventing COVID-19 in healthy pregnant women 18 years of age and older.

The Phase 2/3 trial was designed as a randomized, placebo-controlled, observer-blind study in approximately 4,000 healthy pregnant women 18 years of age or older vaccinated during 24 to 34 weeks of gestation.