The death of a dozen pigs from swine influenza last week in theÂ Philippines reminded me of an incident at Fort Dix, NJ in 1976. The infection of humans with a strain of swine influenza lead to a nationwide immunization campaign to curb a pandemic that never occurred.
An explosive outbreak of febrile respiratory disease raced through the 19,000 personnel at Fort Dix in January 1976. Virological laboratory studies revealed the presence of a new swine influenza strain which was named A/New Jersey/76 (Hsw1N1). The virus infected 230 soldiers and caused severe respiratory disease in 13, including one death.
At the time it was believed that a swine virus had caused the 1918-19 influenza pandemic. Therefore scientists were concerned that the virus had returned to Fort Dix and would soon cause another catastrophic outbreak. Dr. Edwin Kilbourne, a noted influenza researcher, and others convinced the US Public Health Service to contract for the production of 150 million doses of vaccine. In March of 1976 President Gerald Ford announced a program to inoculate every man, woman and child in the United States against swine flu. Immunizations began in October, but only 45 million doses had been distributed when the program was halted in December. By then it was clear that A/New Jersey/76 was going nowhere. An unfortunate consequence was that many individuals developed Guillain-BarrÃ© syndrome, a neurological disease involving muscle weakness, paralysis, and sometimes death.
Why didn’t A/New Jersey/76 spread to the general population? One factor was the limited contact between basic trainees and others who more frequently travel outside the facility. Older personnel may have been immune, because military influenza vaccine formulations from 1955 through 1969 contained a swine influenza component. Competition with concurrent circulating influenza virus strain, A/Victoria, might haveÂ limited the impact of A/New Jersey virus which is believed to transmit poorly among humans.
In retrospect, the swine flu program had many flaws. The vaccine should have been stockpiled until it was clear that an epidemic was taking place. Today we realize that the 1918 influenza virus is derived from an avian strain, not a swine strain – had this information been available in 1976, the immunization campaign would not have taken place. Presumably these and many other errors will not be repeated when the time comes to immunize against the next pandemic strain.
To this day the origin of A/New Jersey/76 virus is an enigma. One theory is that a swine virus was brought to Fort Dix early in 1976 as recruits returned after the holidays. However, none of the personnel who were interviewed admitted to having contact with pigs. The virus seems to have circulated at Fort Dix for about a month, then disappeared.