Moderna said recently it was advancing two Omicron vaccine candidates for the fall, one designed against the BA.1 variant and another against the BA.4 and BA.5.
Moderna and Pfizer are developing updated vaccines to target the Omicron subvariants BA.4 and BA.5, which have gained a foothold in the US over recent weeks.
Moderna said its decision to develop the bivalent vaccines was based on different market preferences for shots against the subvariants.
Bivalent vaccines are designed to target two different coronavirus variants – the original variant from 2020 and the newer Omicron variants.
It also said new clinical data for its mRNA-1273.214 vaccine, designed to target the BA.1 variant, showed significantly higher neutralising antibody responses against the fast-spreading BA.4 and BA.5 compared with the currently authorised booster.
The company’s second booster candidate, mRNA 1273.222, is based on the BA.4/5 strain and is being developed in accordance with recent US Food and Drug Administration (FDA) advice.
Jefferies analyst Michael Yee said though the new data on the company’s BA.1 subvariant-targetting booster shows better durability and antibody response, the original Omicron variant has already shifted in the US and the FDA is likely to approve planned BA.4/5 boosters.
Edits by EP News Bureau