In 1976, an outbreak of the swine flu, influenza A virus subtype H1N1 at Fort Dix, New Jersey caused one death, hospitalized 13, and led to a mass immunization program. After the program began, the vaccine was associated with an increase in reports of Guillain-Barré Syndrome, which can cause paralysis, respiratory arrest, and death. The immunization program was ended after approximately 25% of the population of the United States had been administered the vaccine.