FDA Advisory Panel Supports Moderna, J&J COVID Boosters in Back-to-Back Votes

A vaccine advisory committee to the US Food and Drug Administration (FDA) on Thursday unanimously endorsed booster shots of the Moderna mRNA vaccine for Moderna recipients who are aged ≥65 years, those aged ≥18 years at risk of severe COVID-19 infection, and those who are at risk for extended occupational or residential exposure to the virus. 

The populations that qualify for the Moderna booster mirror those eligible under the emergency use authorization (EUA) granted for the Pfizer-BioNTech vaccine booster in September

The Vaccines and Related Biological Products Advisory Committee (VRBPAC) support an EUA for the booster dose to be administered at least 6 months after completion of the original 2-shot series. The third shot will be a 50-µg injection, ie, half the 100-µg dose given in the first 2 doses.

The VRBPAC recommendation was based on part on analysis of data from Moderna’s phase 2 clinical study of the mRNA-1273 vaccine which the manufacturer amended to offer the 50-µg booster dose to interested study participants 6 to 8 months after completion of the original series, according to a company statement. Before the booster administration, neutralizing antibodies had waned at approximately 6 months, the statement notes, and particularly against circulating variants of concern, including the Delta variant. The 50-µg Moderna booster increased neutralizing titers significantly above the benchmark level established for the phase 3 trial. A similar rise in titers was seen across age groups and, most notably, in adults aged ≥65 years. There were no new safety signals, the company said.

On Friday, according to the Associated Press, VRBPAC also unanimously recommended that the FDA authorize a booster shot of the Johnson & Johnson (J&J) adenovirus-based COVID-19 vaccine. The recommendation is that the booster be administered at least 2 months after the initial shot.

According to J&J studies, a booster dose at between 2 to 6 months can boost the vaccine's efficacy to 94% against symptomatic COVID-19, increasing antibody levels 4- to6-fold when given at 2 months post-original injection and as much as 12-fold when given at 6 months.

FDA regulators are not obligated to follow the advisory panel’s recommendations, but they typically do.

If EUA is granted to either the Moderna and/or J&J boosters, the Centers for Disease Control and Prevention vaccine advisors will convene to discuss final recommendations for which population groups will be eligible. The CDC’s Advisory Committee on Immunization Practices is scheduled to discuss boosters on October 21, 2021.