An advisory committee to the U.S. Food and Drug Administration has given a thumbs up to the nation’s second COVID-19 vaccine.
The independent Vaccines and Related Biological Products Advisory Committee voted 20-0 with one abstention to support mRNA-1273, a vaccine made in collaboration with the U.S. government by Moderna, a decade-old Cambridge, Massachusetts-based biotechnology company.
“There’s no doubt in my mind – it looks like the benefits outweigh the risks from what I’ve seen,” said Dr. Steven Pergam, a committee member and infectious disease and vaccine expert at the Fred Hutchinson Cancer Research Center in Seattle, expressing the group’s consensus.
“What a remarkable scientific achievement this is,” added Dr. James Hildreth, a committee member, immunologist and president and CEO of Meharry Medical College in Nashville, Tennessee. “To go from having a sequence of a virus in January to having two vaccines available in December is a remarkable achievement.”
FDA Commissioner Stephen Hahn could officially authorize the vaccine as soon as late Thursday, with delivery to begin nationwide on Monday.
Unlike the vaccine the FDA authorized last week, made by Pfizer and its German collaborator BioNTech, the Moderna one will be approved for use only in adults. Moderna recently expanded its research trial to teenagers, but they have not been enrolled long enough to draw conclusions.
Pregnant and nursing women, and people who are severely immunocompromised with conditions like HIV, also were not included in large enough numbers to provide clear guidance, although they will not be specifically excluded from receiving the vaccine.
A late-stage trial with more than 30,000 participants, half of whom received the active vaccine and half a salt-water placebo, showed the vaccine to be safe and more than 94% effective.
Most participants endured side effects like arm pain, fatigue and muscle aches, especially after the second of the two recommended doses. But there were very few serious health events among vaccine recipients and all might have happened by chance, according to the company and the FDA.
As it did with the Pfizer-BioNTech vaccine, the FDA will stop short of fully approving Moderna’s, but instead will issue an “emergency use authorization” to speed the process of providing vaccine to the public. The FDA expects the companies to be ready to apply for full approval as soon as next spring, once they have followed trial participants for longer, and have fulfilled a few other requirements.
The two vaccines are both made with a technology called messenger RNA, which uses the body’s own system of protein manufacturing to make a protein found on the surface of the virus that causes COVID-19. Once primed to see this viral protein, the immune system attacks it when exposed again.
The VRBPAC committee spent the first half of Thursday, reviewing company data, hearing from members of the public, and discussing the ethics of when to provide vaccine to the trial participants who received the placebo. They spent several hours asking questions about the data.
Moderna is proposing to allow placebo recipients to receive the vaccine shortly after receiving authorization.
The company wants to keep as many people in the trial as possible to better understand long-term benefits and effects of the vaccine, but give the active vaccine recipients a placebo, and placebo recipients the vaccine, in a “crossover” trial design. Both would be informed about what they got.
The company would supply vaccine that was manufactured for the clinical trials, and would therefore expire if it wasn’t used soon, so it wouldn’t take away from supply designated for health care workers and nursing home residents.
While the trial showed the vaccine to be more than 94% effective at preventing symptomatic COVID-19, it hasn’t been clear whether the vaccine also would prevent transmission of the disease.
Preliminary data Moderna presented Thursday suggested that it will be. There were 38 people in the placebo group and 14 in the active vaccine group who contracted the virus but never developed COVID-19 symptoms, according to Moderna’s data.
Preventing asymptomatic infection will help slow the spread of the virus, and, if confirmed, will allow vaccinated people to confidently stop wearing masks and keeping their distance.
Only about 2% of the trial participants had already had COVID-19 at the start of the study, said Moderna senior vice president Dr. Jacqueline Miller, but the data suggested the vaccine was equally safe for them. “We think the vaccine can be given to people who have been previously exposed,” she said.
Although several people have had severe allergic reactions to the Pfizer-BioNTech vaccine – with at least two reactions reported in the U.K. and two in Alaska – Moderna has not seen any severe reactions to its vaccine.
Although more data is needed to understand these reactions, Dr. Tal Zaks, Moderna’s chief medical officer, said it’s possible that chemical differences between the two vaccines could explain the difference.
Both sets of vaccine makers will be required to follow members of the public as they receive the vaccine to make sure that no new safety problems emerge.
Contact Karen Weintraub at email@example.com
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