Medical researchers are working on a “universal” flu vaccine that could offer immunity from all flu strains for long periods of time, or even throughout a person’s life. That may now be one step closer to reality. A study of antibodies from survivors of the H1N1 swine flu adds proof that scientists are nearer to creating a “universal” flu shot, suggesting that such a vaccine “is really possible,” Patrick Wilson of the University of Chicago, who worked on the paper, told Reuters. Influenza kills between 3,300 and 49,000 people in the U.S. each year, so such a vaccine could have a potentially huge impact. Wilson’s team created antibodies from nine people who were infected in the first wave of the H1N1 pandemic, before a vaccine was available. Five of these were cross-protective, meaning they could interfere with several flu strains (including one strain of H5N1, avian flu). After testing these antibodies in mice, they found they were safe against an otherwise lethal dose of flu; some of these cross-protective antibodies were structurally similar to those other teams have pinpointed as having potential for a universal flu vaccine.