This article incorrectly identified Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy, as a physician. He has a doctorate in environmental health and a master's degree in public health.
Is there a history lesson from the swine flu of '76?
As more and more people receive the H1N1 shot, an earlier vaccine is casting a mysterious shadow over the attempt to immunize 200 million people in the next few months.
A vaccine made in 1976 in response to a different strain of H1N1 influenza led to an outbreak of a rare form of paralysis. Of the 43 million people who were vaccinated, about 400 developed Guillain-Barré syndrome (GBS), and 25 died.
Whether an equally unexpected surprise might be lurking in this year's swine flu shot is a big -- although not publicly acknowledged -- question hanging over the current immunization effort. That possibility is why the Centers for Disease Control and Prevention routinely reports, as it did Wednesday, on whether any notable side effects to the new vaccine have been discovered. (None have.)
Unlike today's bug, the 1976 virus never took off from where it originated at an army base in New Jersey. With nothing to be gained from vaccination, the widespread campaign was halted after less than three months.
For the 15 years after the "swine flu affair," scientists sought to nail down whether and how much the 1976 vaccine increased a person's risk of GBS. Almost nothing, however, was done to figure out how and why the flu shot had that effect. It's an oversight some public health officials are coming to regret.
"We should have made an exhaustive attempt to understand what happened from a biological standpoint," said Michael T. Osterholm, a physician who heads the Center for Infectious Disease Research and Policy.
Both the 1976 strain and the new H1N1 strain are closely related to viruses carried by pigs, making some wonder whether that "swinishness" makes their vaccines more likely to cause unusual effects.
"That is the right question to ask," said Peter Palese, an influenza virologist at Mount Sinai School of Medicine in New York. "And I would like to say that no one really knows."
Researchers stopped looking back at 1976, Osterholm said, when there were no subsequent problems with flu vaccines. "After we had a couple of seasons under our belt when there was no unusual risk to regular flu vaccines, we just let it go," he said.
Today's H1N1 vaccine is made, tested and administered the same way the seasonal flu vaccine is. There's no reason to think it's any more dangerous than the regular flu shot, whose risk of serious side effects is essentially zero.
But that was true of the 1976 vaccine, too.
A spike in cases?
Named after two French physicians who described it in 1916, Guillain-Barré [GEE-yan bah-RAY] syndrome causes weakness and tingling that starts in the legs, but over weeks can affect most of the body's muscles. The symptoms occur because the insulation on the outside of nerve fibers breaks down, damaging the normal conduction of impulses.