"If we had that knowledge then, we might have done things differently," Sencer said. "We did not know what sort of virus we were dealing with in those days. No one knew we would have Guillain-Barre syndrome. The flu vaccine had been used for many years without that happening."
Wenzel also recommended vaccination in 1976. "It was a great effort," he said. "It just had unexpected, unfortunate side effects."
In Mexico, where 22 people have died from the current swine flu outbreak, government officials are under fire for their handling of the situation. But people fail to understand the challenges faced by health officials with such a mysterious threat, said Dr. Peter Katona, an infectious disease expert at UCLA.
"You have to look at not only 1976 but 1918," he said. "The pandemic flu that occurred in 1918 lasted a year and a half. In 1976, we didn't know what was going to happen. The virus might burn out. It might proliferate. These viruses have a mind of their own, and we don't know how to predict what will happen."
CDC officials have been wisely circumspect in their comments about the current outbreak, Sencer said.
"I like the fact that they have said, 'We may change our minds,' " he said. "Don't expect health officials to have the answers overnight. These things need time to be sorted out. We're still in the learning curve."
Dr. Richard Krause, who headed the National Institute of Allergy and Infectious Diseases in 1976, has noted drolly that public health officials involved in the next pandemic flu threat "have my best wishes."