On Jun. 8, 2022, Moderna announced new clinical data on its Omicron-containing bivalent COVID booster candidate, mRNA-1273.214, containing mRNA-1273 (Spikevax) and a vaccine candidate targeting the Omicron variant of concern.

A 50 ﾵg booster dose of mRNA-1273.214 met all pre-specified endpoints including superior neutralizing antibody response (geometric mean ratio) against the Omicron variant one month after administration when compared to the original mRNA-1273 vaccine.The booster dose of mRNA-1273.214 was generally well-tolerated, with side effects comparable to a booster dose of mRNA-1273 at the 50 ﾵg dose level.