Drug manufacturer Moderna is pursuing two vaccines to protect against the omicron variant of COVID-19, reporting positive clinical data.

Moderna is aiming to advance two vaccines to protect against the BA.4 and BA.5 subvariants of the virus. The bivalent Omicron (BA.1) booster candidate, mRNA-1273.214, lead to significantly higher neutralizing antibody responses BA.4 and BA.5 compared to the currently authorized booster (mRNA-1273). That was true regardless of prior infection status or age among adults over 18, greater or less than 65 years old, Moderna announced July 11.

The findings come as BA.5 has become the dominant subvariant in the United States. Cases, hospitalizations and deaths are all on the rise. 

"We are very pleased that our bivalent platform continues to demonstrate better performance than the current booster,” Stephane Bancel, CEO of Moderna, said in a statement. "Today's update extends the remarkable performance of mRNA-1273.214, demonstrating significantly higher titers against all tested variants, including the BA.4/5 and BA.1 Omicron subvariants, and adds to the largest body of data confirming the superiority of a bivalent approach. This superior breadth and durability of immune response following a bivalent booster has now been shown in multiple Phase 2/3 studies involving thousands of participants.”

Moderna shared data in May about the company's ongoing Phase 2/3 study in approximately 800 participants, which showed a 50 µg booster dose of mRNA-1273.214 met all pre-specified primary endpoints and was generally well tolerated, with a reactogenicity and safety profile that was consistent with the currently authorized booster.

Moderna is advancing two vaccines for the fall based on different market preferences for Omicron subvariants. According to Moderna, the mRNA-1273.214 bivalent booster is the only candidate expected to have demonstrated significantly higher titers against the BA.4/5 strain in a clinical trial before the fall booster season compared to the current authorized booster. The second vaccine candidate, mRNA 1273.222, is also based on the two Omicron subvariants and is being developed consistent with recent FDA advice.

"We are working with regulators to advance two bivalent vaccine candidates, mRNA-1273.214 and mRNA-1273.222, based on different market preferences for Omicron subvariants, clinical data requirements, and urgency of starting fall booster campaigns for vulnerable populations,” Bancel said.