So strong was the commitment of the woman who is now the Nevada state health officer that she volunteered to be an experimental subject for a vaccine hurriedly being produced to immunize all 220 million Americans.

"It was the first time CDC employees were allowed to be experimental subjects," Guinan recalled. "We were in the middle of a very worrisome time, and we needed to see what an appropriate dose of vaccine should be."

Shortly after noon Thursday, Guinan had finished yet another staff meeting dealing with the ongoing swine flu outbreak in Nevada. This researcher, whose big brim hats are a reflection of a bout with skin cancer, said she expects public health officials before the winter flu season will once again make a swine flu vaccine available to Americans.

Yet Guinan, who said she suffered no ill effects from two swine flu vaccinations in 1976, admits she isn't sure how many Americans would take the flu shot.

"My biggest concern is that many people won't take it because of publicity about what happened in the past," she said. "But you have to weigh the risks of getting the disease and side effects from the disease. I know I would certainly want my children vaccinated."

A swine flu epidemic in 1976 never materialized amid fears prompted by one flu-related death of a 19-year-old Army recruit at Fort Dix, N.J., and the nonfatal spread of the virus to 500 of his fellow recruits.

But after receiving vaccinations, several hundred people developed Guillain-Barré syndrome, a neurological condition that causes temporary muscle weakness or paralysis. More than 30 people who developed the condition died.

Ten weeks after the vaccination campaign began -- after about 40 million people had been vaccinated -- the program was cut short by a fiery public backlash that questioned the safety of the vaccine.

Guinan said that to this day, despite many studies, no one knows why the 1976 swine flu vaccine caused the neurological condition, in which a person's immune system mistakenly attacks the nervous system.

And that, she said, makes it impossible to say definitively whether something in the cocktail of components for swine flu vaccine can uniquely heighten the risk for Guillain-Barré.

The Institute of Medicine of the National Academy of Sciences concluded in 2003 that the "evidence favored acceptance of a causal relationship" between the 1976 vaccine and Guillain-Barré, but left the "why" a mystery.

One theory has been that the vaccine was contaminated with a bacterium that triggered Guillain-Barré.

That argument has long made the most sense to Paul Rheingold, a New York City based attorney who represented 25 clients on swine flu vaccination cases.

"From the experts I talked to (in preparing cases), I learned that they somehow got an impurity in the vaccine," he recently told the Review-Journal.

Rheingold said he would not be afraid to take a new vaccine for swine flu today.

"I view what happened as a one time thing," he said.

Then-Las Vegas attorney Stewart Bell found it wasn't easy to take on the federal government.

When he tried to help a client who said he lost all feeling in his right leg after receiving a flu shot, he couldn't.

"Somehow his claim apparently got lost in government offices; and without a claim, you can't have a suit," said Bell, now a retired district judge.

The 1978 book "The Swine Flu Affair" revealed that developing Guillain-Barré syndrome was about 11 times greater with the vaccination than without. Yet it noted that the risk was very low; about one in 105,000 who were vaccinated got it.

"Since that time, technology has changed tremendously," Guinan said. "We're a risk averse society. People want zero risk. But you can't guarantee that."

Guinan said it would be irresponsible for public health officials to not do everything possible to combat a new influenza strain that could come back in a second wave in a far more virulent form.

"It would be a disaster for our society not to be prepared if we have the tools," she said.

Side effects can never be ruled out on any vaccination. But as a society, she said, Americans have concluded that the dangers from diseases such as polio and measles, for example, are more serious than risks associated with vaccinations.

Guinan said side effects to the 1976 swine flu vaccination were picked up quickly because so many people were vaccinated in a short time.

One of those affected was Jan Kinney, a 68-year-old Gig Harbor, Wash., resident, who said Thursday she spent a month in the hospital, much of it paralyzed from the neck down, after receiving a swine flu shot in 1976.

"I haven't had any kind of flu shot since," she said. "I'm pretty much OK now, but still a little weak."

Lila Scott, a 66-year-old Las Vegan, didn't get the syndrome, but she did get sick within hours of receiving the vaccine.

"I threw up and had diarrhea for a week," she said Wednesday. "I'd never have a flu shot again."

Though a number of countries have signed deals with vaccine makers that promise them millions of pandemic vaccines as soon as they're available, the United States has yet to reserve vaccine with any manufacturer.

Guinan said, however, that all indications from the CDC are that the United States will make swine flu vaccine available to Americans.

Guinan said she believes public health officials were doing the right thing in 1976 and are doing so now.

"But I think we're in better position to make safe vaccines now," she said.

"I feel it is worrisome that this new strain of flu looks like it has staying power. It will probably continue to move around the world and come back. We don't ever want to see 1918 again. We want to give people the best protection we can."

Contact reporter Paul Harasim at pharasim@reviewjournal.com or 702-387-2908.