Omicron-Containing Bivalent Booster candidate, mRNA-1273.214, demonstrates significantly higher neutralizing antibody response against Omicron subvariants BA.4/5 compared to currently authorized booster.

One month after administration in previously vaccinated and boosted participants, a 50 µg booster dose of mRNA-1273.214 elicited significantly higher neutralizing antibody responses against the Omicron subvariants BA.4 and BA.5 compared to the currently authorized booster (mRNA-1273) regardless of prior infection status or age (adults over 18, greater or less than 65 years old).

Among participants without prior infection, bivalent mRNA-1273.214 resulted in significantly higher neutralizing titers against BA.4/5 compared to the currently authorized booster, with a geometric mean ratio of 1.69 (95% CI: 1.51-1.90)1. One month after booster, BA.4/5 neutralizing titers were 776 (95% CI: 719, 838) for mRNA-1273.214 and 458 (95% CI: 421, 499) for the currently authorized booster. The BA.4/5 geometric mean fold rise (GMFR) from pre-booster levels was 6.3-fold (95% CI: 5.7, 6.9) for mRNA-1273.214 recipients, and 3.5-fold (95% CI: 3.2, 3.9) for mRNA-1273 recipients. Consistent results were demonstrated across subgroups, including in those age 65 and older. The complete data has been submitted for peer reviewed publication and shared with regulators.

Moderna is advancing two bivalent candidates for the fall based on different market preferences for Omicron subvariants. The mRNA-1273.214 bivalent booster is the only candidate expected to have demonstrated significantly higher titers against the BA.4/5 strain in a clinical trial before the fall booster season, when compared to the currently authorized booster. The second bivalent booster candidate, mRNA 1273.222, is based on the BA.4/5 strain and is being developed consistent with recent FDA advice. Both bivalent candidates contain 25 µg of the currently authorized booster (mRNA-1273) and 25 µg of an Omicron subvariant.