Moderna's prototype combination influenza and Covid vaccine outperformed currently authorized standalone shots for those viruses in a clinical trial, the US biotech firm said Monday.

Other companies including Pfizer and Novavax are also working toward combination vaccines to fight respiratory illnesses, but Moderna is the first to report data from an advanced stage clinical rival, giving it a leg up on its rivals.

"Combination vaccines have the potential to reduce the burden of respiratory viruses on health systems and pharmacies, as well as offer people more convenient vaccination options that could improve compliance and provide stronger protection from seasonal illnesses," said CEO Stephane Bancel.

The shot, which uses messenger RNA technology and is called mRNA-1083, was tested in an ongoing clinical trial of 4,000 adults, split into age groups of 50-64, and 65 and older.

In both cases, it produced stronger immune responses compared to the standard flu vaccines for those age groups that were co-administered with SpikeVax, Moderna's current Covid vaccine.

The company plans to present the results at an upcoming conference and to "engage with regulators on next steps."

Moderna is also developing a triple-combo shot against flu, RSV, and Covid.