In February 1976, an outbreak of swine flu struck Fort Dix Army base in New Jersey, killing a 19-year-old private and infecting hundreds of soldiers. Concerned that the U.S. was on the verge of a devastating epidemic, President Gerald Ford ordered a nationwide vaccination program at a cost of $135 million (some $500 million in today's money). Within weeks, reports surfaced of people developing Guillain-Barr syndrome, a paralyzing nerve disease that can be caused by the vaccine. By April, more than 30 people had died of the condition. Facing protests, federal officials abruptly canceled the program on Dec. 16. The epidemic failed to materialize. Medical historians and epidemiologists say ... the decisions made in the wake of the '76 outbreak - and the public's response to them - provide a cautionary tale for public health officials, who may soon have to consider whether to institute draconian measures to combat the disease. I think 1976 provides an example of how not to handle a flu outbreak," says Hugh Pennington, an emeritus professor of virology at Britain's University of Aberdeen. Despite modern advances in microbiology, today's health officials still make decisions in a "cloud of uncertainty," Pennington says. "At the moment, our understanding of the current outbreak is similarly limited. For example, we don't yet understand why people are dying in Mexico but not elsewhere." Howard Markel, director of the Center for the History of Medicine at the University of Michigan and a historical consultant to the CDC on flu pandemics, says the most vexing decision facing health officials is when to institute mass vaccination programs.