Bivalent boosters address two viral strains in the same vaccine. The updated booster contains Moderna’s original vaccine, and a vaccine candidate that targets the Omicron variant.
The vaccine was generally well-tolerated, the company said, with side effects similar to booster doses of the current vaccine.
The 50-microgram bivalent booster, called mRNA-1273.214, generated a stronger antibody response against Omicron than the original Moderna vaccine. Omicron subvariants are driving virtually all the new Covid-19 cases in the United States right now.
In April, Moderna announced its first bivalent Covid-19 booster shot candidate — which combined elements of the current vaccine with updates based on the Beta variant — induced higher antibody responses against all variants of concern, including Omicron, when compared to the company’s original Covid-19 booster shot.