Avian-influenza virus is evolving, so no one can predict the exact genetic makeup of a killer bird-flu strain that would spread from person to person and cause a pandemic. So, if such a strain arose, manufacturers would be hard-pressed to rapidly make enough effective vaccine.
Scientists are looking for ways to stretch the amount of vaccine that would be available. One team now reports that priming people against bird flu with an existing, if not perfectly specific, vaccine might render a specially tailored one more potent during a pandemic.
Currently, three strains of the bird-flu virus, called H5N1, are known to infect people. Nega Ali Goji, a physician at the University of Rochester School of Medicine and Dentistry, and his colleagues identified 37 people who 8 years ago had received two doses of an experimental vaccine against one H5N1 strain of bird flu. That strain from Hong Kong was the first to jump the species barrier from birds to people.