Pfizer's New Flu Shot Could Be a 'Game Changer'

A new mRNA-based flu vaccine from Pfizer has shown greater effectiveness than the standard flu shot in a large Phase 3 trial, according to results published in the New England Journal of Medicine. The vaccine employs the same messenger RNA technology as Pfizer's COVID-19 shot, and experts have long considered flu prevention a logical next step for the platform, per NBC News. No country has yet approved an mRNA flu vaccine, but the trial results suggest the technology could offer a significant improvement over current options.

Dr. Buddy Creech of Vanderbilt University Medical Center called the vaccine a potential "game changer," noting that mRNA shots can be manufactured more quickly than traditional flu vaccines. This speed could allow scientists to more closely match the vaccine to circulating flu strains, which is a key limitation of current flu shots that must be formulated six to eight months in advance.

The trial, funded by Pfizer, compared the new vaccine with Fluzone, a widely used flu shot. More than 18,000 adults across the US, South Africa, and the Philippines received either the Fluzone shot or the new Pfizer one. The mRNA vaccine reduced flulike illnesses by 34.5% compared with Fluzone, with nearly all infections in the study caused by the H3N2 and H1N1 strains of influenza A. The vaccine also offered protection against two influenza B strains. Side effects, including arm pain and fatigue, were more common with the mRNA shot, but most were mild and resolved within a couple of days.

"This really is exciting and promising," Harvard epidemiologist Bill Hanage, who wasn't involved in the study, tells the University of Minnesota's Center for Infectious Disease Research and Policy, or CIDRAP. Despite the promising results, regulatory approval could be challenging. Moderna withdrew its application for a combination COVID-flu mRNA vaccine earlier this year after the FDA requested more data, and Health and Human Services recently nixed nearly $500 million in mRNA vaccine research funding.