Flu Vaccination Lowers Risk of First Heart Attack

The season flu vaccine is associated with a 19% reduction in the rate of acute myocardial infarction, according to a study published in the Canadian Medical Association Journal, which also found that early vaccination in the fall also reduced the rate of heart attacks.

Niroshan Siriwardena, MD, of the University of Lincoln, United Kingdom, and colleagues conducted a large-scale study to investigate the possible link between influenza vaccination and pneumococcal vaccination with acute myocardial infarction. Previous studies, they noted, have demonstrated an association between acute myocardial infarction and preceding respiratory infection; however, “contradictory evidence exists on the influence of influenza vaccination and pneumococcal vaccination in preventing cardiovascular disease.”

Using a matched case-control design with data from family practices in the UK and Wales, the researchers looked at 78,706 patients aged 40 years and older, including 16,016 subjects who had suffered a first acute myocardial infarction, and 62,694 matched controls. Of the patient group, 8,472 had received an influenza vaccination during the previous year.

Siriwarden and colleagues found that influenza vaccination was associated with a 19% reduction in the rate of acute myocardial infarction, and that early seasonal influenza vaccination (between September and mid-November) was associated with a lower rate of acute myocardial infarction than vaccination after mid-November.

“This association and the potential benefit of early seasonal vaccination need to be considered in future experimental studies,” said the authors.

Pneumococcal vaccination, however, was not linked with a reduction in the rate of acute myocardial infarction.

“Our findings reinforce current recommendations for annual influenza vaccination of target groups, with a potential added benefit for prevention of acute myocardial infarction in those without established cardiovascular disease," they wrote. "This benefit may lead to an increase in suboptimal rates of vaccination, particularly among younger patients."

For more:

• Flu shots: Especially important if you have heart disease
• JAMA—Pneumococcal Vaccination and Risk of Acute Myocardial Infarction and Stroke in Men
• New York Times—Cost and Lack of Awareness Hamper Adult Vaccination Efforts