Bundled up against the chill of autumn 2004, 69-year-old Ruby Vogelfanger waits in line outside New York City's District Health Center to receive a flu vaccine. A manufacturing problem with the vaccine produced by Chiron, one of only two suppliers for the United States, forced the company to withdraw its vaccines from the market, resulting in a severe shortage in the 2004-'05 season. On this October day, only a few hundred doses were available, designated for the city's older, "at risk" population.