Flu shot linked to lower heart attack, stroke risk

http://www.health.harvard.edu/blog/flu-shot-linked-to-lower-heart-attack-stroke-risk-201310236795

Posted October 23, 2013, 1:31 pm
Julie Corliss, Executive Editor, Harvard Heart Letter

Ever since the winter of 2003, when my husband came down with nasty case of the flu that led to a three-week bout of walking pneumonia, he’s been religious about getting a flu shot each fall. But the benefits he gains may go beyond warding off respiratory-related problems.

A study published in today’s Journal of the American Medical Association finds that getting the influenza vaccine lowers a person’s odds of a having heart attack, stroke, heart failure, or other major cardiac event—including death—by about a third over the following year.

What’s the connection between flu and cardiovascular problems? “When you get the flu, your body mounts an impressive immune response, which causes a lot of inflammation. As a result, the plaque inside your blood vessels can become unstable, which can lead to blockage and a possible heart attack or stroke,” says study leader Jacob Udell, MD, a cardiologist at Women’s College Hospital in Toronto and a clinician-scientist at the University of Toronto.

Changes in the lungs wrought by the flu virus can lower blood oxygen levels, which makes the heart work harder. The virus can also directly injure heart muscle cells, leading to heart failure or making it worse.

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