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Moderna urges FDA to allow half-dose booster of its Covid-19 vaccine for certain adults

The company is seeking approval for a booster dose of 50 micrograms, or half of the 100 microgram doses used in the primary series of the two-dose vaccine. The company says halving the dose increases protection against the coronavirus while helping the global supply of Covid-19 vaccines.

The FDA’s Vaccines and Related Biologics Advisory Committee is meeting this week to review booster doses for Moderna and Johnson & Johnson Covid-19 vaccines. The FDA had previously cleared recalls of Pfizer’s Covid-19 vaccine for certain adults.

Moderna is requesting authorization of a booster dose of 50 micrograms at least six months after the second dose for certain groups: people aged 65 and over; people aged 18 to 64 who are at high risk of severe Covid-19; and people aged 18 to 64 whose exposure to the coronavirus in their environment or work exposes them to complications or serious illness from Covid-19.

Antibodies have been shown to decrease several months after people have completed their Moderna or Pfizer vaccine series, but protection against serious illness and death remains strong after two doses. However, according to Moderna, trial data and real-world evidence “support interventions to restore or improve” antibodies that have declined over time.

“Data from clinical trials on breakthrough infections as well as actual evidence of reduced efficacy against the Delta variant indicate that a booster dose of mRNA-1273 for people vaccinated more than 6 months previously may be beneficial for restore antibody titers to a higher level than post-dose 2. levels and reduce the number of breakthrough cases, especially against (variants of concern), ”Moderna said in its background paper.

Moderna’s application for authorization includes the results of a study of 171 people who received the authorized doses of 100 micrograms of Moderna’s vaccine and a booster dose of 50 micrograms at least six months later. Moderna also included safety data from another group of Moderna trial participants.

Efficacy against symptomatic Covid-19 has not been evaluated in booster dose recipients, the FDA notes in its analysis published Tuesday.

Similar to Pfizer’s booster dose submission, the FDA did not take a position on the EUA for a booster dose of Moderna’s vaccine in its VRBPAC backgrounder.

Moderna urges FDA to allow half-dose booster of its Covid-19 vaccine for certain adults

“The expected benefit of the booster vaccination will depend on the impact of the booster vaccination on disease reduction compared to the primary series,” the FDA analysis said. “If the Moderna COVID19 vaccine primary series is still effective in preventing important COVID-19-related outcomes, then the benefit of the booster vaccination will likely be more limited than if the effectiveness after the primary series had declined significantly. “

He said factors to consider include the effectiveness of the primary series over time and against circulating variants, the effectiveness of a booster against outcomes such as death, hospitalization and long Covid, the dynamics of the pandemic in the United States and the risks of a dose booster.

“Some real-world efficacy studies have suggested a decrease in the effectiveness of the Moderna COVID-19 vaccine over time against symptomatic infection or the Delta variant, while others have not.” , according to the agency’s analysis. “However, overall, the data indicates that the COVID-19 vaccines currently licensed or authorized in the United States still provide protection against severe COVID-19 illness and death in the United States. There are numerous studies available. potentially relevant, but the FDA has not independently reviewed or verified the underlying data or their conclusions.

Safety of Moderna boosters

In addition to the efficacy, the backgrounders included details on the safety of the booster doses of Moderna’s vaccine.

The two-dose Covid-19 mRNA vaccines made by Moderna and Pfizer have been linked to rare cases of heart inflammation, especially in younger men. Studies have shown that these cases of myocarditis and pericarditis are usually mild.

Moderna urges FDA to allow half-dose booster of its Covid-19 vaccine for certain adults

The FDA analysis notes that pre-authorization trials may not be large enough to fully understand the rare and potentially serious side effects of a booster dose.

“It is currently not known whether there will be an increased risk of myocarditis / pericarditis or other adverse effects after a booster dose of Moderna COVID-19 vaccine,” the FDA analysis indicates. “These risks and the associated uncertainties must be taken into account when assessing the benefits and risks.”

There was a higher rate of swollen lymph nodes after the booster dose compared to the second dose of the Moderna primary series, but safety data did not otherwise show an increased frequency or severity of reactions after a booster dose. booster dose.

What happens next?

On Thursday, the FDA’s independent vaccine advisers are expected to discuss and vote on whether to recommend recalls for the Moderna Covid-19 vaccine to be approved.

Councilors are expected to discuss and vote on whether to recommend the authorization of recalls for Johnson & Johnson’s Covid-19 vaccine on Friday.

Both vaccines are already approved for use in people 18 years of age and older.

VRBPAC members will also hear a presentation on Friday on “mix and match” booster doses.

The committee of independent advisers typically discusses and makes recommendations to the FDA regarding vaccine authorizations and approvals, and the agency then makes the final decision on whether or not to accept the vaccines. If allowed, CDC vaccine advisers are due to meet on October 20 and 21 to discuss whether to recommend them.