• Posted May 8, 2025

Moderna's Combo Flu and COVID Shot Shows Promise

THURSDAY, May 8, 2025 (HealthDay News) — A new vaccine that combines flu and COVID-19 protection in one shot shows promising results, but the U.S. Food and Drug Administration (FDA) says it wants more data before it can be approved.

Moderna researchers reported that the combo shot produced a stronger immune response against COVID-19 and most flu strains than the individual vaccines already on the market.

The results were published May 7 in the Journal of the American Medical Association.

The study focused on adults ages 50 and older and included 8,015 participants. Common side effects included pain at the injection site, fatigue and headaches, The Associated Press reported.

While the vaccine did create antibodies, which help the body fight disease, the FDA still wants proof that the shot also prevents people from getting sick or ending up in the hospital.

But Moderna said it now expects that approval of the shot may not come until 2026.

“I agree in this case with FDA that efficacy data are important to see,” Dr. Greg Poland, a vaccine expert at the Mayo Clinic, told AP.

The current findings are based on antibody levels in the blood 29 days after vaccination. While this shows short-term protection, it's not proof that people actually avoided getting sick.

The flu part of the shot uses mRNA technology, which is also used existing vaccines for COVID and respiratory syncytial virus (RSV). In mRNA vaccines, a lab-created molecule is used to trigger an immune response to fight a virus. 

mRNA has not yet been approved for flu shots, but Moderna is convinced it could speed vaccine production compared to older methods that use chicken eggs or giant vats of cells, AP reported.

Moderna also hopes that combining the shots will help improve vaccine rates. Poland, however, is not sure people will like the idea. He noted that flu is seasonal, while COVID spreads year-round, which makes timing the shot a bit more difficult.

Meanwhile, Moderna President Stephen Hoge told investors that talks with the FDA have been “business as usual,” despite public skepticism about mRNA vaccine safety from U.S. Health Secretary Robert F. Kennedy Jr.

Last week, Novavax announced that the FDA is requiring it to run a new trial of its protein-based COVID vaccine after the agency grants full approval, raising questions about future vaccine updates.

More information

There's more about vaccines at John Hopkins' Institute for Vaccine Safety.

SOURCE: The Associated Press, May 7, 2025