TORONTO - News that public health authorities are investigating human cases of swine flu was, to borrow from a phrase from the inimitable Yogi Berra, like deja vu all over again for Dr. Harvey Fineberg.
Fineberg is one of two academics commissioned by the U.S. government to investigate what became known as "the Swine Flu Affair" of 1976 - the premature pulling of the trigger in the U.S. government's response to the discovery of a cluster of human cases of swine flu among soldiers at Fort Dix in New Jersey.
"It is sort of eerily reminiscent," Fineberg, now president of the U.S. Institute of Medicine, says of hearing that the Centers for Disease Control and California public health officials are investigating human infections with swine flu viruses in two unrelated children who had had no contact with each other or with pigs.
Others involved in the 1976 episode share the sense that history is being replayed before their eyes.
"In fact, I got exactly that email from Dave Sencer - just this morning he said: 'Deja vu all over again,"' says Dr. Walter Dowdle.
Dowdle, retired from the CDC and now with the Atlanta-based non-profit Task Force for Global Health, was the agency's chief of virology during the swine flu incident. Sencer - Dr. David Sencer - was head of the CDC at the time. He was fired in the fallout from the episode.
Both men were in the thick of the response to what was thought to be the start of a flu pandemic with a virus feared to be similar to the 1918 Spanish flu, which killed upwards of 50 million people worldwide.
This time, authorities are being cautious in interpreting the significance of the swine flu cases, saying much more investigation is needed to see if more people have been sick, if some are still falling ill and whether the virus - a swine version of the H1N1 subtype - poses a threat to the population at large or only selected age groups such as children.
"While we have a low index of suspicion that this is a pandemic, we're being very careful in our investigation to rule out every possibility," Dr. Lyn Finelli, of the CDC's influenza division, explained when revealing the existence of the cases on Tuesday.
The caution likely stems from lessons learned from the 1976 response to a pandemic that didn't materialize.
Early that year an explosive outbreak of a respiratory illness swept through recruits at Fort Dix. While samples taken from sick soldiers were being tested, one man died of his illness.
In mid-February, it was discovered several of the men had been infected with swine influenza viruses - viruses similar to that responsible for the 1918 Spanish flu pandemic.
U.S. officials ordered the manufacture of swine flu virus vaccine and the country proceeded to launch a mass immunization program that saw upwards of 40 million people injected with the vaccine.
The feared pandemic never occurred. But the vaccine appeared to trigger a high level of cases of Guillain-Barre syndrome, a type of paralysis that is often, though not always, time limited. The immunization program was scrapped and thousands or recipients filed injury claims.
Fineberg and Richard Neustadt wrote "The Swine Flu Affair: Decision-Making on a Slippery Disease" at the request of then secretary of health Joseph Califano. Looking back on the event, Fineberg says it offers clear lessons on what not to do for officials leading today's investigation.
"One of the big lessons from the last experience that I think does apply is to be careful not to decide more than you need to decide at any particular time," he said in an interview from Washington.
"So the investigation in an intensive way is critical. But you don't start out by declaring or deciding that you're going to embark on whatever immunization or protection program or something at this stage."
Still, Fineberg thinks the swine flu episode may be a double-edged sword in the current context.
"The experience of the swine flu episode itself could be a handicap because it could lead in a way to misplaced expectations that this will be just like the last one," he says.
"And we don't know enough scientifically to be able to say that with confidence."
Dowdle also served as head of the World Health Organization collaborating centre for influenza at the CDC while he was with the agency, so he has had a lot of experience with the famously unpredictable virus.
He says if the swine virus responsible for the California cases continues to spread among people, "I think that would be a new chapter in influenza and we have to see what happens."
"Nothing's surprising with flu. Nothing at all." Dowdle say.
