Flu Shots May Protect Your Heart, Too

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Sure, the flu shot offers protection against the influenza virus, but did you know it might also protect your heart? A recent review of five randomized trials indicated that the flu vaccine may be associated with a lower risk of death in people who have heart disease. The review, published in the Journal of the American Medical Association (JAMA) last month, included over 6,700 patients with an average age of 67, and spanned several decades. Some of the participants received a flu shot, while others received placebos. Reviewers examined how many of the participants eventually experienced a major cardiovascular event, including heart attacks, heart failure, and strokes.

According to the data, participants who had a history of heart disease had a 36 percent reduced risk of experiencing a heart attack, stroke, or death if they received the flu shot. Participants who had recently suffered heart attacks experienced an even more dramatic effect: They were 55 percent less likely to experience another cardiac event. Overall, everyone who was vaccinated had a 19 percent reduced risk of death, regardless of their health history.

Inflammation and Cardiovascular Disease

So what’s the connection? When you contract the flu, your body initiates an immune response that can cause inflammation. If you have cardiovascular disease, inflammation can eventually cause the plaque in the arteries to become unstable, leading to blockage.

Atherosclerosis, the process whereby plaque is deposited in one’s arteries, is a complex interplay between cells and molecules. The plaque consists of cholesterol, other lipoproteins, and various cell types, including white blood cells filled with lipids. According to One Medical Group’s Malcolm Thaler, MD, any inflammatory process, such as the flu, can cause the plaque to become “active,” damage the arterial lining and initiate the formation of a blood clot. If that clot completely blocks the artery, then–if it’s a coronary artery–it can cause a heart attack; if the clot blocks an artery supplying blood to the brain, it can result in a stroke.

The flu can also cause changes in the lungs, which can lower oxygen levels, making your heart work harder. Another complication of the virus is the risk of myocarditis, an inflammation of the heart that can weaken it or cause blood clots.

More research will need to be done to confirm whether the flu vaccine can be considered a safe, low-cost treatment for heart disease. But in the mean time, you can consider the vaccine a safe and effective way to ward off the flu–the Centers for Disease Control and Prevention (CDC) monitor the vaccines every flu season. The most common side effects of getting a flu shot are soreness, redness, tenderness, and swelling at the injection site, or some nasal congestion if the vaccine is administered via nasal spray.

Who Should Get the Flu Shot

One Medical Group recommends flu shots for everyone over six months of age. They’re particularly important for anyone who is pregnant, between six months and 19 years old, over age 50, or has a chronic medical condition. You should also consider getting one if you are a nursing mother or care for someone who can’t care for him or herself, like an elderly parent.

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The One Medical blog is published by One Medical, an innovative primary care practice with offices in Boston, Chicago, Los Angeles, New York, Phoenix, the San Francisco Bay Area, Seattle, and Washington, DC.

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