Moderna’s two bivalent Omicron-targeting booster candidates, mRNA-1273.214 and mRNA-1273.222, demonstrated a superior antibody response compared to a booster dose of mRNA-1273, the company’s prototype vaccine, against Omicron BA.4/BA.5 subvariants in phase 2/3 clinical trials.
Data from the studies showed that the two Omicron-tailored boosters, both at a 50µg dose, produced a higher antibody response against BA.4/BA.5 compared to a 50µg booster dose of mRNA-1273.
The results build upon the data recently published in the New England Journal of Medicine that confirmed mRNA-1273.214 – the company’s BA.1 bivalent vaccine – elicited a superior neutralising antibody response against BA.1 compared to a booster dose of mRNA-1273
The superior response was seen in all participants, regardless of prior infection, with higher antibody levels sustained for at least three months, the company reported.
In terms of safety, the frequency of adverse reactions with both vaccines were similar or lower than that of either a second or third dose of the original vaccine. Additionally, no new safety concerns were identified after approximately one month and three months of follow-up, respectively.
In an exploratory analysis, however, the company said levels of neutralising antibody response dropped nearly five-fold against the emerging BQ.1.1 subvariant when compared with BA.4/BA.5, in an analysis of approximately 40 participants, although the virus neutralising activity demonstrated by both bivalent vaccines remained ‘robust’.
Commenting on the positive results, Stéphane Bancel, Moderna’s chief executive officer, said: “We are pleased to see that both of our bivalent booster vaccine candidates offer superior protection against Omicron BA.4/BA.5 variants compared to our original booster, which is encouraging given COVID-19 remains a leading cause of hospitalisation and death globally. In addition, the superior response against Omicron persisted for at least three months after the mRNA-1273.214 booster.
“Our bivalent boosters also show, in research assays, neutralising activity against BQ.1.1, an increasingly dominant emerging variant, confirming that updated vaccines have the potential to offer protection as the virus continues to evolve rapidly to escape our immunity.”
In July 2022, Moderna announced the advancement of two bivalent candidates for autumn, based on different population health security strategies in different countries. mRNA-1273.214 contains the BA.1 Omicron strain, while mRNA-1273.222 contains the BA.4/BA.5 Omicron strain. Both bivalent candidates contain 25µg of mRNA-1273 and 25µg of an Omicron subvariant.