Here we are in the run-up to another flu season, where many people will happily trade a few dollars for a dose of the magic vaccine.
After all, a 103-degree fever, bad dreams, and feeling like yesterday you played linebacker in an NFL game without padding, can be pretty persuasive. Once you tangle with flu, you will be a flu vaccine believer ever more.
But there is good reason to change that.
Last year at the end of the flu season came some news straight out of left field: influenza vaccine prevents heart attacks. Few people heard it, and even fewer believed it. Most doctors thought it was one of those strange results that would fail to pan out under serious scientific scrutiny. I thought the same.
This year the story of flu shots preventing heart attacks re-emerges, and this time there are good studies backing it up.
Let’s talk about inflammation first. Inflammation has been one of the hottest areas of research in the last decade. It started when we discovered a high C-reactive protein, a blood test showing inflammation was associated with heart attacks. Hmmm!
The more we looked, the more we found inflammation causing trouble. In virtually every system we can find examples of this. Cervical inflammation causes cervical cancer. Brain inflammation causes multiple sclerosis. Less exotically, joint inflammation causes destruction of the joint which we call degenerative arthritis.
Inflammation of the heart valves from Rheumatic fever causes them to become deformed and not work properly. Almost anywhere we look in our bodies, inflammation causes bad stuff. There is even a theory that inflammation causes aging – but that’s another blog.
It turns out that inflammation is bad for blood vessels, too. To understand that, we need to talk about Atherosclerosis: “hardening of the arteries.” That is an unfortunate name for changes that inflammation causes in blood vessels.
It should be called narrowing of the arteries, or plugging of the arteries. Plugged arteries don’t let blood through – that’s a bad thing. No blood results in that tissue dying. Inconvenient if it is heart tissue or brain tissue.
Inflammation of the artery wall starts the whole process of accumulating abnormal cells and cholesterol in the blood vessel wall. This causes the gradual narrowing of blood vessels. Acute (sudden) inflammation can cause the smooth lining of the arterial wall to rip, causing a blood clot and blockage.
What does all this have to do with the flu vaccine? Inflammation is the body’s response to infection among other things. Influenza infection causes a massive amount of inflammation in your respiratory system and we see changes in the bloodstream during the course of infection.
Influenza is a significant insult to patients with borderline blood flow to their heart. It is the proverbial triple whammy. The infection stresses the heart and increases the need for good blood flow. The infection also causes fluid in the small airways, decreasing the oxygen levels in the blood. Finally, the inflammation can trigger an interruption in the blood flow of a crucial coronary artery.
Looking at patients with known heart disease, getting the flu shot cuts down the risk of major cardiac event over 50 percent. If we take all comers – the healthy, the train wrecks, and everyone in between – a flu shot cuts down heart attacks and similar by a third.
Those are numbers that could get the flu vaccine approved as heart treatment. Much of what we do to protect the heart – eat right, exercise, take blood pressure or cholesterol pills – gives a similar reduction in cardiac risk (30 to 50 percent).
It does all that and it even keeps you from getting the flu. Petty cool, huh!
Donald Bucklin, MD (Dr. B) is a Regional Medical Director for U.S. HealthWorks and has been practicing clinical occupational medicine for more than 25 years. Dr. B. works in our Scottsdale, Arizona clinic.
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