An advisory committee to the Food and Drug Administration voted on Thursday 20-to-0, with one abstention, to recommend the Moderna Covid-19 vaccine for an emergency use authorization for people ages 18 and older, determining that the benefits of the vaccine outweigh the risks. This makes the Moderna Covid-19 vaccine the second one to receive a green light from the committee.
The FDA is expected to accept the recommendation from the Vaccines and Related Biological Products Advisory Committee within days, at which time the vaccine, which has an efficacy of almost 95 percent, can begin being distributed to health workers and high-risk populations.
“We’re in an unparalleled crisis, and I did not think an EUA was the way to go, but since the train has left the station, I appreciate that Moderna has given us a very transparent and thorough study that even from the beginning seemed very well organized,” said A. Oveta Fuller, an associate professor of microbiology at the University of Michigan and a temporary voting member of the committee, explaining her vote in favor.
The vote in favor of the Moderna vaccine comes a week after a similar approval for the Covid-19 vaccine developed by Pfizer and BioNTech, which also uses an mRNA platform to generate immunity and is administered as two doses spaced several weeks apart. That vaccine has begun deliveries in the United States this week across all 50 states.
Operation Warp Speed, the $10 billion program from the Department of Health and Human Services aimed at accelerating Covid-19 vaccine development, is expecting to have 12.5 million doses of the Moderna vaccine ready to dispense before the end of the month. Health and Human Services Secretary Alex Azar said at a press conference Wednesday that the program has purchased 100 million doses of the Moderna vaccine and 100 million doses of the Pfizer/BioNTech vaccine to be delivered by the end of March.
Unlike Pfizer, Moderna received direct support from the US government for its research and development, totaling $4.1 billion for clinical trials and manufacturing. Moderna’s vaccine also has less strict cold storage requirements. It demands long-term storage at minus 20 degrees Celsius (minus 4 degrees Fahrenheit) and is stable for 30 days between 2° and 8°C (36° to 46°F). Pfizer and BioNTech’s vaccine, on the other hand, requires temperatures of minus 70°C (minus 94°F) or lower.
An emergency use authorization for the Moderna vaccine would give the company the green light to increase manufacturing to deliver protection from Covid-19 to more Americans. But as with the Pfizer/BioNTech vaccine, there will not be enough doses to go around right away, so health officials will have to make tricky decisions about who gets the shots first.
And an EUA is still a step short of full approval, which means there remain some critical questions about the vaccine that need to be addressed with further clinical trials.
What we learned recently about the Moderna Covid-19 vaccine
The public received details about the Moderna vaccine for the first time outside of the company’s press releases in a briefing document published by the FDA on Tuesday.
Looking at 30,351 participants in their phase 3 clinical trial, Moderna’s latest results showed its vaccine had an efficacy of 94.1 percent against confirmed Covid-19 illness that produced symptoms. The study detected 185 Covid-19 cases in the placebo group and 11 cases in the group that received the vaccine.
The vaccine is administered as two doses spaced 28 days apart. However, it seems to begin to offer protection against Covid-19 shortly after the first dose, with protection continuing to build after the second.
In a presentation to the FDA vaccine committee, Moderna also highlighted that its vaccine not only prevents disease but also seems to prevent infection, including infections that don’t generate any symptoms.
“There were approximately 2/3 fewer swabs that were positive in the vaccine group as compared to the placebo group at the pre-dose 2 timepoint, suggesting that some asymptomatic infections start to be prevented after the first dose,” according to Moderna’s briefing.
This is hugely valuable for fighting the Covid-19 pandemic. The virus has shown an ability to spread between people before the infected show any symptoms, and some of the infected can be completely asymptomatic. That means people can unwittingly spread the virus. But with a vaccine that lowers asymptomatic infections in addition to disease, the spread of Covid-19 can be more easily controlled.
However, the results this week also shed some light on the side effects of the Moderna vaccine. In the phase 3 trial, about 16 percent of people in the vaccine group had a severe adverse reaction, defined by the FDA as a reaction that requires medical attention and prevents people going about their daily lives.
“The most common solicited adverse reactions associated with mRNA-1273 [Moderna vaccine] were injection site pain (91.6%), fatigue (68.5%), headache (63.0%), muscle pain (59.6%), joint pain (44.8%), and chills (43.4%); severe adverse reactions occurred in 0.2% to 9.7% of participants, were more frequent after dose 2 than after dose 1, and were generally less frequent in participants ≥65 years of age as compared to younger participants,” according to Moderna’s briefing to the FDA.
The briefing also acknowledged that there are many critical questions that remain unresolved. One is how long the protection from the vaccine will last, something that will require continued monitoring of the participants in the clinical trial and potential recipients under an EUA.
There is also limited information about how well the vaccine works in people with compromised immune systems and pregnant people. There is no information about the efficacy of the vaccine in people under the age of 18 since they were excluded from the clinical trials. It’s also not clear how well the vaccine blocks transmission relative to other measures like wearing face masks and social distancing.
Moderna has committed to monitoring its trial pool for two years and will conduct additional studies among the people who receive the vaccine under an EUA in order to get answers to these questions.
In the meantime, the FDA will consider the recommendation from its advisers. The FDA granted an EUA to the Pfizer/BioNTech vaccine just over a day after it received a vote of confidence from the vaccine advisory committee, so an authorization for the Moderna vaccine could come as soon as Friday.