(KABC) --
Wouldn't it be nice to have one flu shot last a lifetime? Researchers say they're close to developing such a vaccine, and it would be effective against the bird flu, too.The Universal Vaccine would protect against strains of the flu that haven't happened yet. By altering proteins on the surface of the bird flu virus, researchers developed a strain that can infect human cells. Now they can make a prototype vaccine against that bird flu strain. The same technology will be used to figure out which viral proteins might trigger immunity against all types of flu.