Every fall, you need a new flu shot. That's because today's vaccines train your immune system to recognize specific strains of flu—identified by two proteins on the virus's coat: hemagglutinin and neuraminidase. That's where the 'H' and 'N' come from in H1N1.

Problem is, those proteins are a moving target—they mutate quickly. Once they do, your immune system can't recognize them. And you've got something like the 2009 swine flu, a strain the flu shot never primed us to fight.

To make a more universal vaccine that would work year after year, researchers focused on a smaller, more stable protein called M2. In human strains, the protein has hardly changed since the 1930s.

Researchers engineered an M2 vaccine, and gave it to mice. Then they exposed the mice to lethal doses of human, swine and bird flus. All the vaccinated mice survived—their unlucky counterparts did not. The research appears in the journal Molecular Therapy. [Min-Chul Kim et al., Viruslike particles containing multiple M2 extracellular domains confer improved cross protection against various subtypes of influenza virus]

A good seasonal flu vaccine will still beat the M2 vaccine. But if the M2 gives us insurance against a surprise strain, well, it might be worth a shot.

—Christopher Intagliata

[The above text is a transcript of this podcast.]