On Jul. 8, 2021, Pfizer and BioNTech announced encouraging data in the ongoing booster trial of a third dose of the current BNT162b2 vaccine.

Initial data from the study demonstrated that a booster dose given 6 months after the second dose has a consistent tolerability profile while eliciting high neutralization titers against the wild type and the Beta variant, which are 5 to 10 times higher than after two primary doses.