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Flu shots may prevent heart attack deaths

Higher seasonal risk, study finds

COPENHAGEN -- Add a seasonal flu shot to the list of medicines that can help prevent heart attack deaths, according to a study in the European Heart Journal.

Researchers examined the deaths of 35,000 residents of St. Petersburg, Russia, who died of heart disease between 1993 and 2000. They found more people die of heart attacks during influenza season than at any other time of the year, suggesting those with a history of cardiac disease should be inoculated against the virus.

Heart disease is the leading cause of death worldwide, killing more than 7 million people a year, according to the World Health Organization. Flu infection increases the chance of dying from a heart attack by 30 percent, the study's lead author, Mohammad Madjid, said in an e-mail.

"In the whole population, these numbers accumulate to a large number of deaths which can potentially be prevented by vaccination," said Madjid, a professor at the University of Texas Health Science Center in Houston.

Madjid estimated that as many as 92,000 people die in the United States each year from heart attacks triggered by the flu. About 60 percent of Americans who should have a flu shot get one, and the percentage is lower in Europe. The risk of an influenza pandemic makes vaccinations particularly important, he said.

Health specialists are concerned that the avian flu virus killing birds in Europe, Asia, and Africa may mutate to spread more easily among humans. Fifty-nine percent of the people infected with the disease have died, according to the Geneva-based WHO. At least 291 people have been sickened since 2003 and 172 died.

Among flu-shot makers are Novartis AG, Sanofi-Aventis SA, GlaxoSmithKline Plc, and MedImmune Inc. As many as 10 drugmakers are developing vaccines specifically against a mutated avian influenza virus, including Novavax Inc.

Researchers used autopsy reports rather than death certificates, improving the accuracy of the findings, they said in the study. The group chose St. Petersburg as their study site because autopsies are conducted in 70 percent of deaths and flu vaccinations were uncommon during the period that researchers examined.

During flu season, doctors also should prescribe aspirin and other drugs that stabilize plaque built up in arteries, Madjid and his co-authors advised. The medicines help prevent plaque from ripping free and triggering blood clots which can cause heart attacks.

"Flu causes severe inflammation in the body, including at the coronary artery level," Madjid said. That inflammation appears to "play a key role in plaque rupture and consequent heart attack," he said.