A U.S. Food and Drug Administration advisory panel voted in favor of authorizing a Moderna COVID-19 vaccine booster dose for certain adults at least six months after receiving their first two doses of the same shot.
The booster would be half the dose of the first two shots — 50 micrograms instead of 100 micrograms.
Those who are eligible for a Moderna booster shot include people ages 65 and older and those between 18-64 years old who are either at high risk for severe COVID-19 due to underlying health conditions or workplace exposure.
The same groups of people are eligible to receive a Pfizer COVID-19 vaccine booster shot if they got the Pfizer vaccine for their first two doses, with the second shot administered at least 6 months prior.
Now, the FDA — which usually supports recommendations set by its advisory panel, but is not obligated to — must officially authorize Moderna boosters for emergency use. This decision typically comes soon after the advisory panel declares its vote.
A Centers for Disease Control and Prevention advisory committee will meet next week to discuss safety and efficacy data of Moderna booster shots, as well as who should receive them. If the committee recommends the extra dose, and if CDC Director Dr. Rochelle Walensky gives the green light, boosters will immediately become available to millions of eligible people in the U.S. who initially received the Moderna vaccine.
A document released ahead of Thursday’s meeting indicated it wasn’t immediately clear the FDA felt there was sufficient evidence to support the need for Moderna booster shots at this time.
“Some real world effectiveness studies have suggested declining efficacy of Moderna COVID-19 Vaccine over time against symptomatic infection or against the Delta variant, while others have not,” the FDA said in its review of Moderna vaccine booster data. “However, overall, data indicate that currently US-licensed or authorized COVID-19 vaccines still afford protection against severe COVID-19 disease and death in the United States.”
In the end, FDA advisory panel members decided the benefits of Moderna booster shots outweigh the risks, despite a shortage of data. No specific risks were explicitly mentioned in their discussion.
Data from clinical trials involving 149 participants who initially received the Moderna vaccine showed a booster dose increased antibody levels against the highly infectious delta variant 28 days after receiving the extra dose, according to Moderna officials.
Side effects after a Moderna booster shot were similar to those felt after the first two doses. Injection site arm pain, headache, fatigue and muscle aches were the most common side effects. No serious reactions were reported within a month after receipt of a booster.
The Moderna vaccine has been available in the U.S. since Dec. 18, 2020, when the FDA first authorized it for emergency use.
The FDA has already received an application from Moderna for full approval of its first two doses in people ages 18 and older, however it remains unclear when the group will meet to discuss that step. The vaccine is currently available under an emergency use authorization for those ages 18 and older. Moderna has also filed for emergency use authorization for children ages 12 and older.
More than 187.9 million people in the U.S. are fully vaccinated against COVID-19 as of Oct. 13, according to a CDC tracker, including more than 69.2 million people who have received the Moderna vaccine.
More than 1.5 million people have already received a booster dose of the Moderna vaccine as of Oct. 13. People with weakened immune systems have been allowed to receive a booster of either the Pfizer or Moderna coronavirus vaccines since August.
The FDA panel will meet Oct. 15 to discuss Johnson & Johnson COVID-19 vaccine booster shots in those ages 18 and older.