As expected, a committee of independent advisors to the Food and Drug Administration voted unanimously (19-to-0) Thursday afternoon in favor of authorizing booster doses of Moderna’s COVID-19 vaccine for certain groups.
The groups identified for promotion are people aged 65 and over, those aged 18 to 64 who are at risk of severe COVID-19 due to health concerns, and those over 18. There are 64 who are at risk of COVID-19 due to repeated institutional or commercial exposure. Risks such as health care and essential workers. These are the same groups that were previously authorized to receive the Pfizer/BioNtech boosters.
Like the Pfizer/BioNTech Booster, the Modern Booster is to be given six months or more after the first two doses of Moderna’s mRNA vaccine.
However, one notable difference to Moderna’s recommendation is that the booster will be half the dose of the first two—a 50-microgram dose instead of the 100-microgram dose used in the first and second shots.
In Data submitted to FDA Ahead of today’s meeting, Moderna reported that enhancement with smaller doses was just as effective as larger doses but was likely to cause fewer side effects. Specifically, the company said that both the 50- and 100-microgram booster doses produced a 66-fold or larger increase in antibody levels among clinical trial participants.
The committee also looked at data showing that protection against mild-to-moderate COVID-19 infection is decreasing over time and that older and at-risk groups may become more vulnerable to severe disease over time (though for now). For, safety and death from hospitalization are holding strong).
In that context, in combination with good safety and efficacy data, the FDA committee—the Vaccines and Related Biological Products Advisory Committee (VRBPAC)—was in favor of giving booster doses to select groups.
As in the committee’s deliberations on the Pfizer/BioNtech booster, VRBPAC members strongly opposed opening up the boosters to all – something that the Biden administration has been keen to do. Members once again pointed to stable protection against hospitalization and death among younger groups, who are at relatively higher risk for certain complications, namely myocarditis (inflammation of the heart.)
“Certainly, I don’t agree with [offering boosters] under 18,” said Paul Offit, a polling VRBPAC member and pediatric infectious disease specialist at Children’s Hospital of Philadelphia.
“I am impressed by the fact that we have excellent protection against moderate to severe disease in this country through Delta and all age groups,” Offit said in a discussion after the vote. “And I think we continue to send the wrong message by using words like ‘success’ and making people feel like they’re not safe until they get the third dose.”
Vaccines aim to prevent the worst outcomes — severe disease and death — not prevent mild infections, he and others argued. Although the term “breakthrough infection” gives an impression of vaccine failure, mild infections are always expected at some stage, Offit said. “If the goal of this vaccine is to prevent asymptomatic or mildly symptomatic infections …
Furthermore, that goal and the push to promote all vaccinated people is a distraction from the most important goal, Offit said. “The problem in this country is vaccination of illiterate people.”
For now, Moderna’s booster rollout will only be for people in the identified groups—and, in those groups, only people who initially received Moderna’s vaccine. Yesterday, researchers released preliminary trial data suggesting that mixing and matching vaccines provides better protection — and perhaps better — than sticking with a single type of vaccine for boosters. Although the study was small, it indicated that boosting with Moderna Vaccine may provide the strongest protection regardless of the original vaccination. However, the trial was conducted at shorter time intervals after the first two doses (increasing after 12 weeks, not after six months), and used a larger 100-microgram dose as a booster.
VRBPAC is meeting again tomorrow to discuss mix-and-match data as well as booster data for the Johnson & Johnson vaccine. In the meantime, the FDA will decide whether to sign off on VRBPAC’s recommendations for Moderna Booster authorization today, which it is likely to do. Then, the Centers for Disease Control and Prevention and its committee of advisors will weigh in with further recommendations on who should get the booster.