New Experimental Vaccine Targets Every Flu Type

A new experimental vaccine is showing promise in animal trials, raising hopes that the same mRNA technology that enabled the leading COVID-19 vaccines will tamp down future flu outbreaks.

Researchers led by Scott Hensley of the Univ. of Pennsylvania’s Perelman School of Medicine have developed a universal mRNA vaccine that encodes proteins from all 20 known subtypes of influenza A and B. In mice and ferrets, the vaccine reduced illness caused by even dissimilar subtypes, which means a similar shot for humans could blunt the impact of a newly emerging pandemic flu virus.

“I think it’s a really interesting idea of trying to immunize against everything to provide that pandemic preparedness,” says Jenna Guthmiller, an assistant professor of immunology and microbiology at the Univ. of Colorado Anschutz School of Medicine, who was not involved in the new study. “I’m excited to see it progress forward.”

Flu is a difficult nemesis to beat because so many different subtypes circulate in animal reservoirs, and even the dominant human subtypes change from year to year. Many attempts to develop a universal flu vaccine have focused on finding similar viral proteins across flu subtypes and vaccinating against those. The new version instead packs in the RNA instructions to make multiple viral proteins — one for each subtype of flu out there. This wouldn’t be feasible with a traditional vaccine that contains bits of viral proteins, simply because cultivating those proteins is so...