Topline
Preliminary results from late-stage clinical trials show that a booster shot of Pfizer and BioNTech’s Covid-19 vaccine is highly effective at preventing symptomatic disease, the companies announced Thursday, as experts around the world debate over how and if booster shots should be deployed.
Pfizer said it's Covid booster shot is over 95% effective at preventing symptomatic Covid-19.
Key Facts
A booster shot was 95.6% effective at preventing symptomatic Covid-19 compared to those who did not receive an additional shot, the clinical trial of 10,000 people aged 16 and over showed.
The results showed the booster effectively restores the high levels of protection achieved after the second dose of the Pfizer-BioNTech shot.
The trial was was conducted at a time when the delta variant of Covid-19 was prevalent, showed consistent efficacy regardless of age, sex, ethnicity and other factors, and raised no new safety concerns, with side effects consistent with other clinical studies.
The median time between second and third doses was about 11 months, Pfizer said.
Pfizer chief executive Albert Bourla said the results show “further evidence of the benefits of boosters,” adding that the company plans to share the data with health officials around the world to help plan booster campaigns.
Key Background
The necessity of booster shots has divided regulators and experts around the world. Indicators of waning immunity, the highly infectious delta variant and rising cases have spurred some countries like Israel and the U.S. to push ahead with booster campaigns. Other experts dispute the evidence suggesting immunity is fading—which typically comes from studies assessing indicators like antibody levels or Covid-19 infections—pointing to strong protection against serious illness, hospitalization and death, the key purpose of vaccination. The approach has also clashed with public health leaders around the world, including the leader of the World Health Organization, who believe the widespread use of booster shots by wealthy countries is unfair given the vast inequities in vaccine access. Wealthy countries have so far failed to live up to promises to donate doses of vaccine to poorer nations and pharmaceutical companies are not even close to fulfilling pledges to sell doses to the Covax vaccine sharing initiative. Experts believe the stockpiling of vaccines risks the emergence of dangerous new variants and prolonging the pandemic for everyone.
What To Watch For
The U.S. Food and Drug Administration authorized booster shots for Moderna and Johnson & Johnson’s Covid-19 vaccines Wednesday. A booster shot for Pfizer’s vaccine was authorized last month. The regulator greenlit the mixing and matching of vaccine doses, meaning someone fully vaccinated with another vaccine and who qualifies for a booster can take a different dose for the booster. The Centers for Disease Control and Prevention are slated to meet this week to discuss the FDA’s decision on Moderna and Johnson & Johnson, paving the way for widespread rollout.
Big Number
11.2 million. That’s how many Americans have taken an extra vaccine dose so far, according to the CDC. The numbers include people who would have received Pfizer boosters last month when they were approved as well as immunocompromised people eligible for additional shots of Pfizer or Moderna in August.
Further Reading
Wealthy Countries Delivered Just 14% Of Covid Vaccine Doses Promised To Poorer Nations, Report Finds (Forbes)
“Where a Vast Global Vaccination Program Went Wrong” (The New York Times)
