Pfizer says COVID-19 booster restores vaccine efficacy to 95.6%

Pfizer and its German partner BioNTech on Thursday shared results from the Phase 3 trial of their COVID-19 vaccine booster, saying the additional third dose showed 95.6% efficacy against symptomatic disease.

The trial involved more than 10,000 people 16 and older who had previously received the Pfizer-BioNTech primary two-dose vaccine. Pfizer said the booster "restored vaccine protection against COVID-19 to the high levels achieved after the second dose, showing a relative vaccine efficacy of 95.6% when compared to those who did not receive a booster." 

"These results provide further evidence of the benefits of boosters as we aim to keep people well-protected against this disease," Pfizer CEO Albert Bourla said in a statement. "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."

Bourla said Pfizer-BioNTech plans to share the results with global health authorities in support of a "rollout of booster doses around the world."

Close-up of glove hands of nurse holding Covid booster vaccine

FILE - Photo of the hands of a nurse as they prepare to administer the Pfizer booster shot on Oct. 6, 2021, at Northwell Health in New Hyde Park, New York. (Photo by Alejandra Villa Loarca/Newsday RM via Getty Images)

The vast majority of the nearly 190 million Americans who are fully vaccinated against COVID-19 have received the Pfizer or Moderna options, while about 15 million have received the Johnson & Johnson vaccine.

The government says all three U.S. vaccines continue to offer strong protection against hospitalization and death from COVID-19, and that the priority is getting first shots to the 66 million eligible but unvaccinated Americans who are most at risk. But with the spread of the extra-contagious delta variant and signs of waning immunity against milder infections, the nation is moving toward a broader booster campaign.

Last month, Pfizer boosters started being offered to U.S. seniors and younger adults at high risk from COVID-19 because of poor health, jobs or living conditions — at least six months after their initial vaccination. Last week, the FDA advisory panel recommended the same approach for half-dose Moderna boosters.

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This story was reported from Cincinnati. The Associated Press contributed.