On Oct. 14, 2021, Moderna confirmed that the U.S. Food and Drug Administration’s (FDA) Vaccines and Related Biological Products Advisory Committee (VRBPAC) had recommended that the FDA grant an Emergency Use Authorization (EUA) for a booster dose of the Moderna COVID-19 vaccine (mRNA-1273) at the 50 ﾵg dose level for people aged 65 and older; people aged 18 to 64 who are at high risk of severe COVID-19; and people aged 18 to 64 whose exposure to COVID-19 puts them at risk for COVID-19 complications or severe illness.

The positive vote was unanimous with 19 VRBPAC members recommending EUA. The booster dose was to be administered at least six months after completion of the primary series.

The VRBPAC based its recommendation on the totality of scientific evidence, including a data analysis from the Phase 2 clinical study of mRNA-1273, which was amended to offer a booster dose of mRNA-1273 at the 50 µg dose level to interested participants 6-8 months following their second dose (n=344). Neutralizing antibody titers had waned prior to boosting, particularly against variants of concern, at approximately 6 months. Notably, a booster dose of mRNA-1273 at the 50 µg dose level boosted neutralizing titers significantly above the Phase 3 benchmark. After a booster dose, a similar level of neutralizing titers was achieved across age groups, notably in older adults (ages 65 and above). The safety profile following the booster dose was similar to that observed previously for dose 2 of mRNA-1273.