Moderna's combo Covid and flu mRNA shot outperforms current vaccines in large trial

Moderna’s combined Covid and flu shot outperformed the existing standalone vaccines for both viruses, according to the results of a phase 3 clinical trial published Wednesday in the Journal of the American Medical Association.

Moderna’s combined Covid and flu shot outperformed the existing standalone vaccines for both viruses, according to the results of a phase 3 clinical trial published Wednesday in the Journal of the American Medical Association. 

The vaccine uses the same messenger RNA technology as Moderna’s approved Covid vaccine. (There are no approved mRNA-based flu shots.)

The trial, funded by Moderna, included more than 8,000 adults ages 50 and older who were enrolled in October and November 2023. For people ages 50 to 64, the new vaccine was compared to Moderna’s Covid vaccine and the flu shot Fluarix. For people 65 and older, it was compared to the Covid vaccine and a different flu shot, called Fluzone, which is a stronger dose typically given to older adults. The trial participants either got the existing shots, or the new combination vaccine plus a placebo shot. (This way, both groups got two injections.)

The main goal of the trial was to see whether the combination vaccine generated more antibodies in blood samples than the current shots against multiple strains of influenza and the XBB.1.5 Covid variant. This so-called serological testing is a common way for researchers to gauge how well a vaccine shot might work and how long the protection might last.

The trial found that antibody levels were higher for Covid and all but one influenza strain in people who got the combination vaccine, compared to those who got the existing shots in both groups.