MONDAY, June 10, 2024 (HealthDay News) -- An experimental vaccine that could offer one-stop prevention for both COVID-19 and influenza is showing positive results among older adults in trials, maker Moderna announced Monday.

The shot — for now called mRNA-1083 — "has met its primary endpoints, eliciting a higher immune response than the licensed comparator vaccines used in the trial," Moderna said in a statement.

The phase 3 trial is only another step towards approval of the dual-purpose shot, which won't be okayed in time for this year's flu season.

However, "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," Moderna CEO Stéphane Bancel said in the statement.

According to the company, the new vaccine contains "components of mRNA-1010, Moderna's vaccine candidate for seasonal influenza, and mRNA-1283, Moderna's next-generation COVID-19 vaccine candidate."

In a trial involving more than 4,000 adults ages 65 or older, the mRNA-1083 vaccine triggered immune responses to three influenza variants as well as to the SARS-CoV-2 virus (which causes COVID) that equaled those of vaccines already approved against either flu or COVID. The three influenza variants are H1N1, H3N2 and B/Victoria.

Similar results were also seen in another group of about 4,000 people between 50 and 64 years of age, Moderna said.

The trial was "blinded," meaning that neither the patients nor the people conducting the trial knew who got which vaccines.

Moderna added that the new combo vaccine's safety profile appeared similar to that of vaccines targeted to just one virus.

The new findings have not yet been peer-reviewed, although Moderna said it plans to submit the trial results for publication and to possible review by the U.S. Food and Drug Administration (FDA).

The real issue is whether vaccine-fatigued Americans will avail themselves of the dual-purpose vaccine, should it become available, said Sue Peschin, president and CEO of the non-profit Alliance for Aging Research.

Speaking with CNN, she noted the percentage of Americans who get any form of vaccine has dropped.

For example, only a quarter of eligible Americans have gotten the latest COVID-19 vaccine, according to a presentation to the FDA last week. Uptake of the flu shot did rise slightly last year, with the Centers for Disease Control and Prevention reporting that nearly half of adults got one last season.

“We want to see that go up and if there’s a way to do that by combining the vaccines, then that’s better for everyone because it helps protect everyone in the community,” Peschin said. “We would love to see the combination vaccines come to market if the FDA deems them safe and effective.”

More information

Find out more about preventing flu at the Mayo Clinic.

SOURCES: Moderna, news release, June 10, 2024; CNN