Anticipating the authorization decision, Gen. Gustave F. Perna, who is overseeing the federal effort to distribute vaccines, said Monday the government was preparing to ship almost 6 million doses of the Moderna vaccine to 3,285 locations in the first week after approval.
“It will be a very similar cadence that was executed this week with Pfizer, where we’re hitting initial sites on Monday, [followed] on Tuesday and Wednesday,” Perna said.
Early in the meeting Thursday, the FDA addressed an issue that did not involve the Moderna vaccine directly: reports of allergic reactions to the Pfizer-BioNTech vaccine, which was authorized by the FDA last Friday, including in two health-care workers in Alaska, one of whom was hospitalized. Both are recovering.
“While the totality of data at this time continue to support vaccinations under the Pfizer [emergency use authorization] without new restrictions, these cases underscore the need to remain vigilant during the early phase of the vaccination campaign,” FDA vaccine expert Doran Fink said.
The agency is working with the companies to revise the fact sheets provided to patients and health-care professionals, and will highlight a requirement that facilities administering the vaccine ensure that treatment for a severe allergic reaction is immediately available.
The endorsement from the independent panel of outside advisers came two days after the FDA issued a detailed data review confirming that in the company’s clinical trial, the two-shot regimen was 94 percent effective at preventing illness, and particularly effective against severe illness.
The vaccine has not caused major safety problems, according to the FDA and Moderna, a biotechnology company with headquarters in Cambridge, Mass.
Moderna developed its vaccine in partnership with the National Institute of Allergy and Infectious Diseases, with the government underwriting the research and development of the vaccine and the advanced purchase of 200 million doses, bringing the government investment to $4.1 billion.
The FDA reviews of the Pfizer-BioNTech and Moderna vaccines cement the success of a new genetic vaccine technology, which could be used to rapidly create vaccines for other diseases.
Older vaccines work by injecting dead or weakened virus to teach the immune system to recognize the real pathogen. In contrast, the messenger RNA technology at the core of the Moderna and Pfizer-BioNTech vaccines delivers a strip of genetic material called RNA, encased in a fat bubble, to a person’s cells.
Once inside a cell, the messenger RNA co-opts the machinery used to make proteins to build tiny replicas of the spike protein that studs the outside of the coronavirus. The immune system learns to recognize — and block — the spike..
Paul A. Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and a member of the FDA advisory committee, said Wednesday on CNN that the two vaccines are similar in safety and efficacy. Asked whether people will have a choice of which to get, he replied, “There is not a lot of vaccine out there, so you are going to be asked to get the vaccine that the area has.”
In Moderna’s trial, 30,000 people were randomly assigned to receive either two shots of a vaccine given four weeks apart, or two saline shots. Neither the participants nor the people running the trial knew who was in which group.
Investigators then waited as people were exposed to coronavirus in their daily lives, to see if there were more cases of covid-19, the disease caused by the virus, in the group that did not receive the real vaccine. They counted cases starting two weeks after the second dose, to measure how well the vaccine protected participants after the immune system had mustered a full response.
The numbers were decisive: There were 196 cases in the trial, all but 11 of them in the group that received the placebo shots. There were 30 cases of severe covid-19 and one death from covid-19 in the trial, all in the group that received the placebo.
There was a suggestion that a first dose of vaccine afforded some protection from the virus, but the data lack key information. “These data do not provide sufficient information about longer term protection beyond 28 days after a single dose,” the review said.
One of the major outstanding questions about this and other coronavirus vaccines is whether they prevent infection, not just disease. Since most cases of covid-19 are asymptomatic, that question has major implications for how to best use the vaccines and whether people will need to continue wearing masks and social distance despite being vaccinated.
Additional data filed by Moderna provided a hopeful hint that the vaccine, which was shown to prevent symptomatic cases of disease, might also help prevent asymptomatic infections starting after the first shot. A vaccine that protects only against illness, but not infection, would still be incredibly valuable. But epidemiologists have worried about a worst-case scenario, in which people stop wearing masks but could remain vulnerable to asymptomatic infections and spread the disease.
Larry Corey, a virologist at the Fred Hutchinson Cancer Research Center who co-leads the government’s clinical trial network responsible for testing coronavirus vaccines, is working on a proposal for a trial that could test whether vaccines afford such protection, potentially giving shots to college students and having them swab themselves everyday. He said he hopes that study could begin in January.
There were three cases of Bell’s palsy, a temporary facial paralysis, in the group that received the Moderna vaccine, compared with one case in the placebo group. The people who developed Bell’s palsy had other risk factors, and the rate was similar to that expected in the general population. But the FDA concluded “a potential contribution of the vaccine to the manifestations of these events of facial palsy cannot be ruled out.”
Lymph node swelling was more common in the group that received the vaccine, with 16 percent of participants experiencing the symptom after the second dose. There were no severe allergic reactions, a concern that has emerged after two cases were reported in the United Kingdom after the first injections of the Pfizer-BioNTech vaccine.
Enrollment in Moderna’s trial was slowed down this summer because scientists were concerned it lacked sufficient racial diversity to determine whether it truly protected those at highest risk of the disease. In the end, a fifth of participants were Hispanic, 10 percent were Black and four percent were Asian. More than 40 percent of the participants were either over the age of older than 65 or had medical conditions that increased their risk of severe disease.
“The trial enrolled the right people at risk,” Corey said. “For us who were designing the trial and enrolling the people, that’s so fantastic.”
December 18, 2020 at 05:00AM
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FDA advisers recommend second coronavirus vaccine, with agency action expected soon - The Washington Post
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