For decades, researchers have been doggedly pursuing a universal flu vaccine--one that would protect against the evolving influenza virus for years rather than just a single season--with little success. The bug mutates so quickly that a new vaccine must be specially formulated each year. But a relatively new strategy, targeting a rarely seen portion of the virus, is now showing some success.

A novel vaccine developed by microbiologist Peter Palese and collaborators at Mount Sinai School of Medicine in New York showed protective effects in rodents against three different flu strains, with protection ranging from mild (against hemagglutinin 1, such as that of the H1N1 or "swine" flu) to middling (against the avian flu H5 subtype) to absolute (against the common H3 flu subtype). While the results are far from perfect, the proof-of-principle demonstrates the potential for a universal flu vaccine.

"This has been the dream of people in the influenza field forever and ever--finding a broadly cross-reactive vaccine, instead of having to make yearly changes that account for variance within a subtype, let alone between subtypes," says Robert Webster, an influenza expert at St. Jude Children's Research Hospital in Memphis, who was not involved in the research. "If this is as good as the mouse says, it'll be fantastic."