Moderna announced new clinical data on its bivalent Omicron-containing booster, mRNA-1273.214. The data indicated that 90 days after administration as a fourth booster dose in previously vaccinated and boosted participants, a 50-mcg booster dose of mRNA-1273.214 produced a superior neutralizing antibody response against Omicron BA.1 when compared with a 50-mcg booster dose of mRNA-1273 in all participants, regardless of prior infection. Moreover, superior performance against Omicron BA.1 was also durable, with greater antibody titers sustained through 3 months.

In addition, mRNA-1273.214 demonstrated significantly higher neutralizing antibody responses against Omicron BA.4/BA.5 compared with mRNA-1273 28 days after administration, as previously reported. Potent responses were also noticed against the Omicron BA.2.75 variant 28 days after administration, indicating that the bivalent booster elicits broad cross-neutralization against Omicron variants.

Stéphane Bancel, CEO of Moderna, stated, "Our bivalent boosters continue to demonstrate a strong, enduring response to COVID-19 variants of concern. Clinical trial data now indicates that the superior immune response produced by our bivalent booster has durability for at least three months. As COVID-19 remains a global threat and a leading cause of death globally, this is an encouraging development, showing that a bivalent booster dose will offer important protection leading into the winter months."

Identified adverse effects of mRNA-1273.214 were comparable or less severe than those of either a second or third dose of the original vaccine. Additionally, no new safety concerns were discovered in the 3-month follow-up.

The company expects interim safety and immunogenicity results of its Omicron BA.4/BA.5–targeting bivalent vaccine, mRNA-1273.222, to become available later this year. Data will be produced from a clinical study designed in accordance with regulatory guidance for bivalent booster vaccines against COVID-19.

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