Pfizer told the FDA Wednesday that data from its clinical trials suggests a third shot of its coronavirus vaccine may be necessary six months after the second dose because of waning efficacy.
Why it matters: The FDA’s advisory committee on Friday is expected to review Pfizer’s clinical trials and other supporting and conflicting data on coronavirus booster shots and make recommendations on whether more Americans 16 years and older should receive an extra dose.
- Pfizer included the clinical trial data in a presentation that it will deliver to the advisory committee.
By the numbers: Pfizer data from its trials showed that the efficacy of its coronavirus vaccine, which it developed with BioNTech, degrades by around 6% every two months after the second dose, increasing the likelihood of breakthrough cases.
- The company said data from an analysis of breakthrough cases also suggested that they were more common among people who had received their second dose earlier than others.
- The drop in effectiveness was “due to waning of vaccine immune responses” and not the Delta variant of the virus escaping the protection offered by the vaccine, Pfizer said.
The other side: International public health experts — including two FDA vaccine leaders who are leaving the agency this year — wrote a new paper published in The Lancet this week that booster doses are not necessary for the general public right now, Axios’ Bob Herman reports.
- They said current evidence suggests that vaccines are still extremely effective in preventing severe illness and death from COVID-19 and that the doses used for booster shots would save more lives by inoculating populations that are currently unvaccinated.
- The experts did support booster shots for immunocompromised people.
The big picture: The Biden administration hopes to soon start offering booster shots to everyone six months after their second dose.
- The World Health Organization, however, is currently strongly opposed to developed nations offering extra doses to their general public while developing countries struggle to procure enough doses for their citizens.
- WHO director-general Tedros Adhanom Ghebreyesus called on developed countries last week to forgo booster shots through the end of the year.
- The Biden administration has argued that additional shots are needed to curb the spread of the virus in the U.S. and that developed countries can both administer boosters and deliver doses to developing countries.