FDA grants approval for Moderna's mRNA flu vaccine for adults 50 and older

The Food and Drug Administration approved Moderna's mFlusiva, an mRNA influenza vaccine intended for adults 50 years of age and older. Full approval was granted for people 50-64 after a trial of 40,000 participants showed a roughly 27% reduction in flu cases compared with an existing vaccine, while an accelerated approval was issued for those 65 and older based on a smaller study that demonstrated a strong immune response relative to a high-dose vaccine currently used for seniors. Moderna said the vaccine caused temporary side effects such as injection-site pain, fever, headache, fatigue and aches, occurring somewhat more frequently than with standard flu shots.

The new vaccine joins several other flu products already on the market, including three formulations specifically recommended for people 65 and older. Because mRNA technology can be manufactured more quickly than traditional methods, experts note the addition could be valuable if the influenza virus undergoes rapid changes that require new vaccine formulations.

"The FDA granted full approval for mFlusiva’s use in people ages 50 to 64, based on a study of 40,000 people that found the new shot reduced flu cases by about 27% compared with another routinely used flu vaccine brand," Moderna said.

"For people 65 or older, the biotech and pharmaceutical company said the FDA granted what’s called accelerated approval for the shot -- based on a smaller study showing it generated a strong immune response compared with an existing high-dose vaccine for seniors – while it conducts an additional postmarketing study," the company added.

The approval follows a prior dispute in which a senior FDA official initially blocked the application, prompting a review by an independent advisory panel that later recommended approval.