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Safety of Swine Flu Vaccine to Face Tough Scrutiny

TUESDAY July 21, 2009 -- A high-level U.S. government decision in 1976 to vaccinate 43 million people against swine flu backfired -- badly.

Not only did the dreaded outbreak never materialize (illness never spread beyond 240 soldiers stationed at Fort Dix, N.J.) but some 500 Americans who did get vaccinated came down with a rare neurodegenerative condition called Guillain-Barre syndrome, which many experts believe was linked to the shot. Twenty-five of those 500 people died.

Now U.S. health officials are considering a fall immunization campaign that could involve an unprecedented 600 million doses of vaccine for the currently circulating H1N1 swine flu vaccine.

How do health experts know 2009 won't be a repeat of the 1976 fiasco? Are there any guarantees the vaccine will be safe?

The short answers to those questions, according to the experts, are "we don't know" and "no."

"There will be no way to be certain until trials this summer," said Dr. Harvey Fineberg, president of the U.S. Institute of Medicine and author of The Epidemic That Never Was, a look back at the 1976 outbreak.

"And if we talk about relatively rare side effects on safety, by probability they will not show up until more people get the vaccine. This speaks to the need for continued surveillance. But, as far as efficacy and immediate reactions, we will have good information on that with the round of trials planned for this summer," he added.

Another expert agreed.

"We won't know that the vaccine is safe until it's given to large numbers of people," said Dr. Scott R. Lillibridge, a professor at the Texas A&M Health Science Center School of Rural Public Health in Houston and executive director of the National Center for Emergency Medical Preparedness and Response. "Every vaccine has a trade-off and a safety profile."

A more complete answer is that the public health system has come a long way since 1976 and should be able to head off or at least detect and interrupt such problems, experts said.

The situation today is already very different from that seen three decades ago. Take health officials' ability to monitor the spread of a disease and pick up on adverse events, for example.

"The Department of Health and Human Services has a number of things in place that will be used to catch early signals if there's any kind of issue and to monitor the safety of vaccinations as they're performed," said Dr. John Treanor, professor of medicine and of microbiology and immunology at the University of Rochester Medical Center, in New York.

Experts also pointed to more sophisticated detection, connectivity and surveillance systems worldwide that are able to monitor changes on an hourly basis.

That should mean that governments are better able now than in 1976 to quickly switch gears as new information emerges.

"The biggest policy error in 1976 was rolling everything up into a single go-no-go decision early in the year," Fineberg said. "That problem has already been averted. Decision-makers and policy-makers are taking it one step at a time, keeping everyone informed. They have avoided that error."

He added: "The second problem [in 1976] was more a strategy problem. They failed to ever think about times when they could reconsider. I think that is something the current crew has avoided by making clear that they are thinking about on-ramps and off-ramps and trying to identify exactly what would go into those decisions. That is an ongoing process."

Rather than using 1976 as an example of public health strategy gone awry, expert suggest looking at the 2003 response to SARS as a public health success story. That outbreak, which emerged in Asia, was detected and contained in relatively short order, although not without casualties.

The pattern of today's swine flu is already vastly different than that in 1976, with experts basing decisions on entirely different factors.

"Although the name is the same, the situation we face right now is completely different than that faced in 1976," said Marc Lipsitch, professor of epidemiology at the Harvard School of Public Health in Boston. "The 1976 vaccination program followed an outbreak with little or no transmission beyond there [Fort Dix], and was largely based on the fear of a larger outbreak than the existence of a larger outbreak."

The H1N1 swine flu that first surfaced in the United States in mid-April has already infected an estimated 1 million Americans, killing close to 200 and has exploded through national borders.

Globally, the World Health Organization reports close to 100,000 cases of swine flu in more than 100 countries resulting in 429 deaths. In June, the organization declared a pandemic, triggered by the rapid spread of the virus across North America, South America, Europe, Australia and regions beyond.

"In 1976, we ended up having lots of people vaccinated and then having only a small number of people who got sick," said Lillibridge. "If there's no disease killing people or hurting people then the side effects of the vaccine dominate attention."

Lipsitch added: "If there had been a major flu epidemic with tens of thousands of deaths in 1976, I don't think there would have been much of a concern that the vaccine caused side effects."

All vaccine decisions are made under tremendous uncertainty, Lipsitch said, and the current situation is no exception.

But there are important differences.

"Not only do we know more today but we know that the virus is transmissible, it can transmit in all parts of the world and it can kill people," Lipsitch said. "The likely benefit of a vaccine is in saving many lives and we don't know how many but certainly more than have been lost so far, which is several hundred. The risk-benefit analysis is very, very different than in 1976."

More information

For the latest on the current H1N1 swine flu outbreak, visit the U.S. Centers for Disease Control and Prevention.

Posted: July 2009


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