BLOG: Flu Vaccines – it’s not too late

It’s not too late to get the flu vaccine!  The CDC says vaccinations are still beneficial and should continue to be offered through January and February.

Here we are. It is after the holidays and time for the winter flu season.  I respond to the flu by crawling under the covers, turning out the light, and miraculously emerging three days later.  My wife, on the other hand, prefers chicken-noodle soup, with attentive coddling and assurances that the house remains tidy.

Although we may feel terrible, most people do not die from the flu. Rather, they die from aggravation of underlying illnesses such as heart failure or chronic obstructive pulmonary disease (COPD), secondary infections (e.g. pneumonia), or heart attacks.  This blog will focus on heart attacks.

A number of studies document the correlation between influenza and heart attacks.  Data from the Spanish flu pandemic in 1918 showed an increase in heart attacks for up to a year following the influenza peak.  Why does the flu increase the risk of heart attacks?

Infectious agents (e.g. influenza, chlamydia, CMV, etc.) initiate or aggravate chronic vascular or systemic inflammation. The inflammatory molecules (cytokines) contain a number of factors that recruit fibroblasts and foam cells, damaging the endothelial lining of artery walls and causing plaque buildup.  This causal relationship between inflammation and atherosclerosis is well vetted in basic research over the past 40 years.  In addition to promoting inflammation, the Influenza virus destabilizes vulnerable plaques, resulting in clot formation (thrombosis), and sudden blockage of vessel blood flow causing heart attacks and strokes.

If there is a relationship between influenza and heart attacks, can we decrease the likelihood of heart attacks following the influenza season?  Thankfully, the answer is YES!  Several studies show a reduction in the incidence of heart attacks after flu vaccination. One indicates that vaccination reduces acute myocardial infarctions (most commonly called a heart attack) by 45% in immunized 40 to 64-year -olds, and by 33% in immunized individuals aged 65 or older.  Total mortality is also reduced. In Sweden, vaccinated patients have a 57% reduction in total mortality compared to an unvaccinated group. In the U.S., it is estimated that vaccination could save 91,000 lives per year.

The effectiveness of the influenza vaccine is similar to that of other recommended therapies.  Smoking cessation reduces acute heart attacks by 32% to 43%, cholesterol reduction (e.g. statins) by 19% to 30%, and antihypertensive drugs by 17% to 25%.

In Chattanooga, vaccines can be obtained from local drug stores, primary care providers or the public health department. Although we do not give vaccines at the Heart Institute, it does not diminish the importance of the flu vaccine for preventing heart attacks during these winter months. Remember, prevention is the best medicine. Get your flu vaccine, wash your hands frequently, and avoid contact with those who have upper respiratory symptoms.

Dr. David J. Wendt