An independent committee of experts recommended that the Food and Drug Administration authorize the Moderna COVID-19 vaccine for people 18 and older. This is the second COVID-19 vaccine to go before the committee — the first, made by Pfizer and BioNTech, was authorized last week. The agency is expected to issue an authorization for Moderna’s vaccine within a day or two.
“This is a really opportune time for us to move science forward,” said Hayley Gans, a committee member and professor of pediatrics at Stanford University Medical Center, during the committee’s deliberations. The evidence available for benefits of the vaccine outweighs any issues, she said. “That really supports us being able to, with the pandemic in the background, really move forward, and finally provide a safe and effective way to get to herd immunity.”
The FDA’s review of the vaccine ahead of the meeting confirmed that it’s safe and 94 percent effective at preventing symptomatic COVID-19, all but guaranteeing a vote of confidence. The Vaccines and Related Biological Products Advisory Committee (VRBPAC), which met to discuss the data, spent the day discussing the additional questions remaining around the vaccine and how Moderna should handle vaccinations in the placebo group of its clinical trial.
To test how well the vaccine works, during the clinical trial some people received a placebo, or an inactive shot instead of the vaccine. Moderna said during its presentation that the company plans to offer active vaccines to people who got the placebo quickly. Pfizer and BioNTech, on the other hand, plan to wait for participants in the placebo group to become eligible under their vaccine prioritization plans before telling them of their placebo status. Moderna would vaccinate this group with doses set aside for the clinical trial, which the company argues means study participants aren’t cutting in line.
Telling the placebo group that they did, in fact, receive a placebo limits the ability to study the vaccine. If people know they didn’t get a vaccine, their behavior might change, and once they actually get a vaccine, researchers will no longer have a control to compare with the vaccinated group. That worries the VRBPAC, which would like to collect data for as long as possible. The pharmaceutical companies, though, both said they think they have a responsibility to offer vaccines to the placebo group.
The committee also pointed to a handful of issues the clinical trials still haven’t addressed. Moderna still doesn’t know, for example, if the vaccine can protect against asymptomatic cases of COVID-19 — stopping infection with the coronavirus entirely — or if it just prevents symptoms. Early data from Moderna hints that it could block asymptomatic infection. Trial participants who didn’t have symptoms were tested for the coronavirus between their first and second dose. People who took the vaccine were less likely to test positive than people in the placebo group. More answers on that question are coming in January, Moderna said.
Moderna is still analyzing data collected after it submitted the vaccine for authorization. There were 450 more cases of disease reported in the trial after that submission, and that will add to the understanding of the vaccine’s efficacy.
As this vaccine and the Pfizer and BioNTech vaccine are distributed throughout the country, the pharmaceutical companies and federal agencies will track how well they work and how safe they are in the real world. Already, regulators are finding effects that weren’t seen in clinical trials — a handful of allergic reactions and cases of anaphylaxis were reported in the US and United Kingdom in people vaccinated with the Pfizer and BioNTech vaccine, for example. The FDA is investigating the US incidents.