Oct. 14 (UPI) -- An advisory committee for the Food and Drug Administration voted Thursday to recommend the Moderna COVID-19 booster shot for people age 65 and older and those with underlying medical conditions or who are at higher risk of exposure to the virus.
In the first day of a two-day meeting to evaluate requests from both Moderna and Johnson & Johnson to authorize their booster doses, the panel voted 19-0 to approve Moderna boosters beginning at least six months after completion of the initial two-dose regimen.
Friday's meeting will evaluate the extra Johnson & Johnson dose, which is produced by subsidiary Janssen. The experts will also discuss a "mix-and-match" approach to boosters, using different types of vaccines from different manufacturers.
"We are grateful for the opportunity to present the clinical data package for our COVID-19 booster vaccine to the FDA's advisory committee today," Moderna officials said in a tweet. "We thank the committee for their review & for their unanimous vote in support of EUA of the 50 [microgram] booster dose."
The Vaccines and Related Biological Products Advisory Committee's recommendation now goes to the FDA for approval. If approved, the Centers for Disease Control and Prevention then would review it and make a final decision in the next couple of weeks.
Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in introductory remarks that booster shots are necessary because "vaccine effectiveness against mild and moderate disease appears to wane over time," which could lead to blood clots and "long COVID" in some cases.
Israeli researchers also presented findings on the use of booster doses of the Pfizer-BioNTech vaccine in that country, which, like the Moderna product, is a messenger RNA vaccine.
The booster doses helped contain the fourth wave of the pandemic with few serious side effects apparent, said Dr. Sharon Alroy-Preis of the Israel Ministry of Health.
Several members of the advisory committee cautioned that there was insufficient data and a lack of diversity in the people chosen by Moderna for the clinical trials.
Only 149 subjects were involved in the trial, and 95.3% of them are White and 60.4% of them are women, according to the FDA.
Patrick Moore, American Cancer Society professor at University of Pittsburgh, pointed out the issue but nonetheless voted yes. He said he went with his gut feeling.
"Data are not perfect. But it's an extraordinary time and we have to work with imperfect data," said Dr. Eric Rubin, editor-in-chief of New England Journal of Medicine and a committee member.
On Sept. 3, Moderna requested authorization of its half-dose booster shot to be used at least six months after the two-dose primary series for those 65 and older and those above 18 who have underlying medical conditions or are at higher risk of exposure, including healthcare workers, teachers and prisoners.
This is the same population group for which Pfizer and BioNTech's COVID-19 third dose was approved to distribute on Sept. 24.
Moderna's therapeutic area head, Jacqueline Miller, told the panel that the Moderna's booster shot leads to a 17-fold increase in antibody level countering the delta variant. Miller also said that the adverse reactions of the booster shot are not more severe than those of the second dose.
During Thursday's meeting, a clear distinction was made between the half-dose (50 mcg) booster shot and the full-dose (100 mcg) third dose of Moderna's COVID-19 vaccine. The 100 mcg third dose was made available to only the immunocompromised individuals on Aug. 12. Some experts questioned how Moderna plans to prevent confusion during the distribution process.
"We recognize that this will require some education and enforcement and so we are preparing to send a 'Dear Health Care Provider' letter explaining how the doses are to be administered," Miller responded.
Last month, the FDA approved a third shot of the vaccine made by Pfizer for people over 65, as well as recipients between 18 and 64 who are at high risk of severe illness and who face frequent institutional or occupational exposure to COVID-19.
The agency recommended the Pfizer booster dose six months after the second shot.
Almost 9 million people in the United States have received a booster dose of the Pfizer vaccine over the past few weeks, according to the Centers for Disease Control and Prevention.
FDA scientists announced findings for both the Johnson & Johnson and Moderna boosters this week.
Tuesday, they said that data show that Moderna's two-dose regimen provides sufficient immunity that precludes the need for a third dose. They said, generally, a Moderna booster seems unnecessary to protect against the more contagious Delta variant.
A study released by Moderna in August showed that its vaccine remained 93% effective in recipients six months after the second dose, and that a third shot created a "robust antibody response" against the Delta variant.
In their remarks about the Johnson & Johnson shot on Wednesday, FDA scientists said its booster appears to offer added protection, but they're unsure when is the best time to receive the extra dose. Johnson & Johnson recommends the booster between two and six months after the first shot.
The Johnson & Johnson vaccine, unlike those from Moderna and Pfizer, requires only one dose.
In their evaluation for a booster, the scientists said some of the data provided by Johnson & Johnson was incomplete. For example, they said, the company offered only a small sample size of recipients who received a booster after six months.
Johnson & Johnson in September reported that a booster after two months was 100% effective in protecting recipients from severe COVID-19, and 75% effective in preventing symptomatic COVID-19 in recipients worldwide.
The company said the booster had greater efficacy in the United States, 94%, in preventing symptomatic COVID-19.
Johnson & Johnson also noted that one dose of the vaccine showed to be 79% effective against infection in the United States between March and late July, and 81% effective in preventing hospitalization.
Another development that may impact the distribution of booster doses came on Wednesday, when a National Institutes of Health-led study concluded that "mixing and matching" booster doses appears to be effective, and will also be reviewed by the FDA advisory committee.
In fact, the study said that people who received the Johnson & Johnson vaccine are better off getting a booster dose of the Moderna or Pfizer formulation.
That means that the FDA and CDC, for example, may ultimately approve a Moderna booster for people who received the Pfizer vaccine and vice versa. It's not yet known when the FDA panel will make its recommendation on that possibility.
The NIH study is expected to be a factor in the FDA panel's recommendations for Moderna and Johnson & Johnson boosters.
After the panel makes its recommendations, they will have to be approved by the FDA and CDC before Americans could begin to receive the Moderna and Janssen boosters. The soonest the agencies could grant that approval is Oct. 22.