Pfizer and BioNTech Release Phase III Trial Data Supporting Efficacy of Booster Doses

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Pfizer and BioNTech’s Phase III trial demonstrated 95.6% booster efficacy relative to participants who received placebo.

Pfizer and BioNTech announced favorable results of a Phase III trial evaluating the efficacy of booster doses for their COVID-19 vaccine on Oct. 21, 2021. Participants who were given a booster vaccine in the trial had a disease reduction rate of 95.6% relative to those who did not receive a booster.

The trial included more than 10,000 participants aged 16 years or older. Participants—individuals who were administered the two-dose Pfizer-BioNTech COVID-19 vaccine—were randomized 1:1 to receive either a 30-µg booster dose or placebo. The median time between administration of the second dose and the booster was 11 months.

Symptomatic COVID-19 occurrence was measured from at least seven days after booster or placebo, with a median follow-up of 2.5 months. Five members of the group who received the booster dose contracted COVID-19, while 109 members of the non-boosted group contracted the virus.

“These important data add to the body of evidence suggesting that a booster dose of our vaccine can help protect a broad population of people from this virus and its variants,” said Ugur Sahin, CEO and co-founder of BioNTech, in a Pfizer press release. “Based on these findings we believe that, in addition to broad global access to vaccines for everyone, booster vaccinations could play an important role in sustaining pandemic containment and a return to normalcy.”


Last month, Pfizer and BioNTech received an Emergency Use Authorization (EUA) from FDA for the use of their COVID-19 vaccine as a booster among certain populations. This week, both Moderna and Johnson & Johnson also received EUA’s permitting booster doses.

Source: Pfizer