• Posted November 21, 2025

New Trial Shows Pfizer’s mRNA Flu Shot Beats Traditional Flu Vaccine

FRIDAY, Nov. 21, 2025 (HealthDay News) — Pfizer’s mRNA flu vaccine worked better than a standard flu shot in a large Phase 3 trial, researchers reported.

The results, published Nov. 19 in The New England Journal of Medicine, suggest that mRNA technology may help improve protection in future flu seasons.

The Pfizer flu vaccine uses the same type of messenger RNA science that was used in the company’s COVID-19 shot.

More than 18,000 adults took part in the Phase 3 trial during the 2022–2023 flu season. Some received Pfizer’s mRNA flu shot, while the others received Fluzone, a standard seasonal flu vaccine.

Researchers found that people who got the mRNA flu shot had 34.5% fewer flu-like illnesses than those who got Fluzone. There were 57 cases in the mRNA group compared to 87 cases in the Fluzone group.

Nearly all were caused by two common influenza A strains: H3N2 and H1N1. The mRNA vaccine also protected against two B strains: Victoria and Yamagata.

The vaccine could be a "game-changer," Dr. Buddy Creech of Vanderbilt University Medical Center in Nashville, Tennessee told NBC News.

He noted that mRNA vaccines can be made faster, which could help scientists better match the shot to the strains that actually end up circulating each year.

Even so, experts warn that approval may not come easily. Several public officials have recently raised doubts about mRNA vaccines, and in August the U.S. Department of Health and Human Services (HHS) canceled nearly $500 million in funding for mRNA vaccine research.

"Despite all the advantages of mRNA, I’m concerned that our current HHS has no or little interest in the science," Dr. Peter Hotez of Baylor College of Medicine in Houston, told NBC News.

Pfizer says discussions with federal regulators are happening, but the company has not shared a timeline for approval.

Side effects were reported with both shots, but they were more common among people who got the mRNA vaccine. About 5.6% reported fever, compared with 1.7% of those who got the traditional shot.

Most symptoms were mild and went away within a day or two, researchers said.

More information

The Mayo Clinic has more on flu shots.

SOURCE: NBC News, Nov. 19, 2025