Pfizer says its booster shots were 95.6% effective in Phase 3 trials

COVID-19 vaccine
Posted at 8:44 AM, Oct 21, 2021

Pfizer and BioNTech on Thursday said a booster shot of their COVID-19 vaccine was 95.6% effective in preventing infection from the virus compared to those who did not receive a third dose.

In a press release Thursday, the companies said that Phase 3 trial results showed that the efficacy of the booster shots "was consistent irrespective of age, sex, race, ethnicity or comorbid conditions."

The Phase 3 trials included 10,000 individuals aged 16 and older who got a booster shot at a median time of 11 months after receiving their second dose of the Pfizer COVID-19 vaccine.

Some of the participants were given a booster, while others were given a placebo. According to the companies, those who received the booster saw a 95.6% reduction in disease compared to those who received the placebo.

Pfizer noted that a portion of the trial took place while the spread of the more contagious delta variant was prevalent.

"These results provide further evidence of the benefits of boosters as we aim to keep people well-protected against this disease," said Albert Bourlam], Pfizer's chairman and CEO. "In addition to our efforts to increase global access and uptake among the unvaccinated, we believe boosters have a critical role to play in addressing the ongoing public health threat of this pandemic. We look forward to sharing these data with health authorities and working together to determine how they can be used to support the rollout of booster doses around the world."

The Centers for Disease Control and the Food and Drug Administration have already recommended booster shots for certain Americans who received the Pfizer vaccine. That includes people who are 65 and older, people who live in long-term health facilities, people who have underlying medical conditions and people more at risk for contracting the virus due to their jobs.

Earlier this week, the FDA approved a plan that would allow physicians to administer a brand of booster shot that differs from their original dose. That plan still needs approval from the CDC.