COVID-19 Roundup: FDA Mulls Moderna, J&J Booster Data; First Study on 'Mixing and Matching’ Vaccines; and More

Moderna Seeks FDA Approval for Booster Shot at One-Half Dose

An advisory committee to the U.S. Food and Drug Administration (FDA) voted unanimously Thursday to recommend granting emergency use authorization (EUA) to Moderna’s COVID-19 vaccine booster. In submitting its application to the FDA, Moderna asserted that a half-dose booster shot of its COVID-19 vaccine can provide a substantial boost in antibody levels — higher than what they had been before the second dose.

The FDA’s Vaccines and Related Biological Products Advisory Committee agreed that Moderna’s booster is safe and effective for certain individuals starting six months after they become fully vaccinated with Moderna’s second shot. The unanimous recommendation paves the way for the agency to approve the EUA for Moderna’s booster within days.

Moderna states that the rate of breakthrough infections, referring to mostly mild COVID cases among the fully vaccinated, represents falling levels of neutralizing antibodies from its vaccine six to eight months after a second dose. Antibodies is one measure of the immune system’s response to infection. Moderna did not to argue that its vaccine protection wanes against severe disease or hospitalization.

Moderna’s booster, or third dose, contains half of the mRNA vaccine found in each of the first and second doses. As was the case with the Pfizer-BioNTech booster shot recently approved by the FDA, Moderna is requesting the EUA for a booster dose at least six months after completion of the primary series in the following:

• individuals 65 years of age and older,
• individuals 18 through 64 years of age at high risk of severe COVID-19, and
• individuals 18 through 64 years of age whose frequent institutional or occupational exposure to COVID-19 puts them at high risk of serious complications.

Before the advisory’s committee’s vote on Thursday, the FDA declined to take a position on whether to back booster shots of Moderna’s vaccine — just as they did prior to approval of the Pfizer third dose. In both cases, the FDA said clinical data shows two doses are still enough to protect against severe disease and death from COVID-19 in the U.S.

“Some real-world effectiveness studies have suggested declining efficacy of Moderna COVID-19 Vaccine over time against symptomatic infection or against the Delta variant, while others have not,” the FDA states in a document on the agency’s website. “However, overall, data indicate that currently US-licensed or authorized COVID-19 vaccines still afford protection against severe COVID-19 disease and death in the United States.”

The FDA’s outside advisory committee is also meeting on whether to recommend emergency authorization of a booster shot of Johnson & Johnson’s vaccine (read below). The panel’s votes are not binding, but the FDA regulators usually follow the advice of the experts.

Johnson & Johnson: Second-Shot Boosts Protection Against COVID to 94%

Johnson & Johnson has submitted data on a second-shot booster of its COVID-19 vaccine to the U.S. Food and Drug Administration (FDA), asserting that the additional dose boosts protection from 75 percent to 94 percent given two months after the first dose.

When a booster was given six months after the single shot, antibody levels increased “nine-fold one week after the booster and continued to climb to 12-fold higher four weeks after the booster. All rises were irrespective of age,” Johnson & Johnson stated in a news release of findings submitted to the FDA. On Friday, an independent FDA advisory committee unanimously recommended authorizing J&J’s booster shot, given at least two months after the first dose. Of the three available COVID vaccines in the U.S., J&J’s is the only one with a single shot.

Johnson & Johnson’s single-shot vaccine, developed by its Janssen Pharmaceutical Companies, received “emergency use authorization” (EUA) in the U.S. in February of this year. About 15 million U.S. adults have received the one-dose vaccine.

In a new analysis of the Johnson & Johnson booster data, FDA scientists questioned the reliability of the test — known as “psVNA assay” — used by Johnson & Johnson to measure study participants’ immune response six months after the initial vaccine shot. The FDA’s analysis states that “psVNA assay” is “not yet qualified or validated.” The FDA added: “It is likely that the results seen are due to the low sensitivity of the psVNA assay used.” In a separate study by the National Institutes of Health (NIH), preliminary data found that people who received a Johnson & Johnson vaccine may get significantly stronger protection with a booster shot from the Moderna or Pfizer-BioNTech vaccines.

Nonetheless, the FDA advisers recommended J&J’s second shot. The FDA could issue a separate regulatory action that would allow Johnson & Johnson recipients to receive a booster shot of Moderna or Pfizer-BioNTech’s vaccines.

The FDA did indicate that a J&J booster shot given two months after the first shot, based on separate trial sponsored by the company, seemed to provide more encouraging results. “Although not independently confirmed by FDA from datasets, summaries of the data suggest there may be a benefit in a second dose administered approximately 2 months after the primary dose,” the FDA states in its analysis.

The agency will consider the recommendation of the FDA advisors, which is not binding, before issuing a final decision on booster approvals.

NIH Study: ‘Mixing and Matching’ Vaccine Boosters Safe and Effective

A highly anticipated study from the National Institutes of Health (NIH) has found the practice of “mixing and matching” COVID-19 vaccine boosters to be safe and effective, according to preliminary data released this week. However, those who received the single-shot vaccine from Johnson & Johnson are better protected by getting a booster from Moderna or Pfizer — instead of a second shot from J&J, the data indicates.

The most significant finding: If you initially got either the Pfizer or Moderna two-shot vaccines — as did the vast majority of the population — you can switch among the two mRNA vaccines for a potent booster. 

The study, which has yet to be peer-reviewed, involved 458 volunteers. They were divided into nine groups with about 50 volunteers in each group. Those who initially got the two-dose Moderna vaccine got either another Moderna shot, a Pfizer shot or a Johnson & Johnson shot as a booster four to six months after their primary immunization. People who initially got the two-dose Pfizer vaccine got either another Pfizer shot or a Moderna or J&J booster. And people who got the one-shot J&J vaccine, either got another J&J shot, or a Moderna or Pfizer booster.

Researchers measured antibody levels in all those groups two weeks and four weeks after the booster shot. Those who got the Moderna vaccine for their original shots and Moderna again for their booster appear to have gotten the best immune response. They were followed by those who got Pfizer and then were boosted by Moderna, and then those who initially got Moderna and were boosted by Pfizer. The differences among the mRNA vaccines — from Pfizer-BioNTech and Moderna — were too small to make a significant difference in protection in most groups.

The most significant finding indicated that people who initially got the J&J vaccine received a much more robust immune response if they got Pfizer or Moderna as their booster. The antibody levels of people in those groups went up 10 to 20 times higher, compared to those who got another J&J shot.

Merck: Anti-COVID Pill Cut Hospitalization or Death by 50% in Clinical Trial

Made by Merck and Ridgeback Biotherapeutics, first oral antiviral treatment to fight COVID-19 is being considered for “emergency use authorization by the U.S. Food and Drug Administration (FDA).

The experimental antiviral treatment, molnupiravir, which comes in capsule form, was found to halve the risk of hospitalization or death among adults with mild to moderate symptoms from COVID-19, according to Merck. Just 7 percent of those the pill in a clinical trial were hospitalized or died, compared with 14 percent of participants who received a placebo. Nearly 400 people took part in each of those two groups.

That FDA approval process could take weeks, but the antiviral treatment could become available before the end of the year. The pill is meant for unvaccinated people. It should be taken within five days of developing symptoms, Merck states. People who have been sick for longer than five days may not be eligible

If authorized, molnupiravir would be the first antiviral pill to treat COVID-19. However, public health officials caution that vaccination remains the best protection against severe illness and hospitalization from COVID-19. White House chief medical advisor Anthony Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases, has said that Merck’s announced clinical trial results are “very encouraging.” But he added that vaccines remain “our best tools against COVID-19” by preventing infection and illness.