A booster shot of the BioNTech/Pfizer vaccine is 95.6 percent effective against Covid-19 compared with two shots and a placebo, the companies said on Thursday, citing preliminary results from the first randomized, controlled trial on boosters.
Ugur Sahin, the head of BioNTech, said the “important data” added to the body of evidence suggesting that a booster dose could help “protect a broad population of people from this virus and its variants”.
“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,” he said.
In a trial with 10,000 participants who had all completed a two-shot Pfizer regimen, half were randomized to receive a further equal-strength dose of the shot, and half a placebo. Five cases of Covid were registered in patients receiving the booster compared with 109 who were given a placebo.
The trial took place during a period when the Delta coronavirus variant was prevalent, and the median time between second and third doses was about 11 months, with a median follow-up time of two and a half months.
Andy Hill, a senior visiting research fellow in pharmacology at the University of Liverpool, said the trial was “very important” because it provided a “much stronger” level of evidence.
“It is randomized and measures effects on new infections. This is a big step forwards from previous studies of other vaccines which only measured effects on antibody levels,” Hill said. “This new trial is much more reliable.”