The flu shot might just prevent a heart attack

A study just published in the Journal of the American Medical Association (JAMA) shows that patients who had received influenza vaccine had a lower risk of cardiovascular problems.

This study is a meta-analysis that reviewed data from several other previously done studies. (Udell, JA et al., JAMA. 2013;310(16):1711-1720. doi:10.1001/jama.2013.279206)

It has been known that patients who have had a recent case of the flu are at higher risk of having a cardiovascular event, like a fatal or non-fatal heart attack. The reason(s) for this is unclear. It is not known if a recent case of the flu predisposes you to plaque rupture in a coronary artery causing a heart attack, or whether it produces heart failure, or causes arrhythmias, or some other mechanism is involved.

Heart via Shutterstock

Heart via Shutterstock.

This study was not investigating the cause of the cardiac event, but rather, whether a recent influenza vaccination lowered the risk of a cardiovascular event. They defined a cardiovascular event as: hospitalization for a heart attack, fatal heart attack, heart failure, unstable angina or the need for a rapid coronary revascularization (e.g., heart catheterization, stenting), among others.

There were over 6,500 patients studied in all. Some had a previous cardiac history (like a heart attack), while others had no record of any cardiovascular disease. They were a mixture of men and women, with an average age in the mid-60s.

After review and analysis, the information shows that there is a decreased risk for cardiovascular events for people who receive influenza vaccine.

As the authors state:

“[I]nfluenza vaccination was associated with a lower risk of major adverse cardiovascular events within 1 year. Influenza vaccination was particularly associated with cardiovascular prevention in patients with recent ACS [Acute Coronary Syndrome]. Future research with an adequately powered multicenter trial to confirm the efficacy of this low-cost, annual, safe, easily administered, and well-tolerated therapy to reduce cardiovascular risk beyond current therapies is warranted.”

Even though each of the six studies from which the data for the meta-analysis was taken differed somewhat in their designs, the authors say:

“Still, despite differences in trial designs, risk of bias, sample size, cardiovascular risk of participants, circulating influenza activity, vaccination strategy, duration of follow-up, and number of observed events, our meta-analysis demonstrated a consistent association between influenza vaccination and a lower risk of cardiovascular events.”

This study supports earlier studies that suggested similar findings. And influenza vaccination has been recommended for several years as a means to possibly lower the risk of heart attacks.

More research is needed, specifically a study to look at exactly that question: Does preventing influenza by means of a vaccine directly cause a decrease in cardiovascular events.

However, since influenza vaccination is already recommended virtually universally, this just adds another reason why flu shots are a good idea.


Mark Thoma, MD, is a physician who did his residency in internal medicine. Mark has a long history of social activism, and was an early technogeek, and science junkie, after evolving through his nerd phase. Favorite quote: “The most exciting phrase to hear in science... is not 'Eureka!' (I found it!) but 'That's funny.'” - Isaac Asimov

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  • Whitewitch

    I did not mean to imply that my provider is not getting the shot – I am only saying that in times past the pressure from her for me to get one was quite intense and this year she told me her story and then dropped it. If someone wants the shot – more power to them…for me it is a no-go

  • benb

    Costco charges $14.99 for a flu shot. The dark days are coming and we’re all gonna be crowded in around the fire to keep warm.

  • Doctor John

    You flu shot is free, period. Doesn’t matter whether it’s done at the local pharmacy or at the doctor’s office. Free is free.

  • 2patricius2

    Thanks.

  • Bomer

    I think it’s Koger and CVS ’round here that offer flue shots for $5 and that’s without insurance. Not sure what the cost, if any, is with insurance.

  • http://www.americablog.com/ Naja pallida

    They discovered an all-inclusive antibody that protects against the 16 A-subtypes a few years ago. Will probably be only a few more years before there is a vaccine developed, but how long it takes to come to market usually depends on the the commercial viability, not the need. But it does give hope for other wide-spectrum antibodies, and more effective vaccines.

  • 2patricius2

    I know there are clinical trials going on to develop more effective and inclusive flu vaccines. I participated in one last year.

  • 2patricius2

    Yes, they should. I have Medicare. They have that info, and they don’t charge me.

  • emjayay

    The pharmacy should take your insurance for the cost of the shot, shouldn’t they?

  • http://www.americablog.com/ Naja pallida

    Problem is, the influenza virus is extremely variable – resulting in hundreds of possible subtypes, and vaccinations can only really cost-effectively cover three or four at a time. So they tend to manufacture the vaccines with the most common varieties predicted for a given flu season. Or specifically targeted ones for known outbreaks. That doesn’t mean there aren’t a dozen other strains you could catch. Plus, vaccinations can take anywhere from two weeks to a month to be effective. Many people will put off getting vaccinated until they feel they’re at risk, but that really doesn’t do you any favors. Most flu carriers are asymptomatic, or have symptoms so mild that they don’t pay them much attention. Not to mention, most people don’t know the differences between influenza and rhinovirus (the common cold). So many reports of “I got the vaccine and got sick anyway!” are people getting a cold, or other infection. The idea that a health care professional would forgo vaccination because they got sick, to me, is ridiculous. They spend day in and day out intentionally being around sick people. It is only sensible for them to be vaccinated for everything they possibly can. I work with animals, and have never seen an actual case of rabies in person, but got vaccinated anyway. That’s just sensible, you don’t know what you’re going to encounter.

    The flu vaccine isn’t as long-term effective as other disease vaccines, but it should give an otherwise healthy person good protection from those particular strains for up to two years, maybe longer… depending on your own immune system. Which is why they recommend that people with compromised immune systems keep on top of their vaccinations. But with so many potential strains, and the ease of catching the virus, it’s a lot like one of those old cartoons with the guy trying to plug holes in a dam with his fingers and toes. If you notice with other diseases, like the measles outbreak recently, when there is a large enough population of unvaccinated people, things just reach a critical mass and an outbreak happens.

  • Whitewitch

    The flu shot might be as effective as 50% (although it can be far less some years), it also seems to expire after a year (or at least losses its benefit) and seemingly if you are old you next the extra powerful shot (but of course they aren’t sure when that is). According to my doctor, who normally bugs the heck out of me to get the silly thing – she is no longer pressuring people after experiencing the non-effectiveness herself.

  • http://www.rebeccamorn.com/mind BeccaM

    Depends on the pharmacy. A lot of ‘em don’t charge a co-pay.

  • perljammer

    Yes, that is one of the provisions already in effect. Apparently not widely known, but nonetheless true. See http://aspe.hhs.gov/health/reports/2012/PreventiveServices/ib.shtml

  • silas1898

    My county holds clinics with free flu shots for all county residents. Just show a driver’s license or utility bill to prove residency. People who don’t get shots must never have had the flu. I don’t want to do that again.

  • Gene

    Yes – flu shots and other shots as well (like the tetanus shot I had last month) are free with health insurance (I have BC/BS Federal). I get my shots at a CVS Minute Clinic – takes longer than a minute, but less time than going to my doctor.

  • cole3244

    don’t be fooled america the socialist obama admin is putting micro chips in your body in lieu of the flu vaccine, be afraid , be afraid, lol lol lol!!!

  • http://AMERICAblog.com/ John Aravosis

    I didn’t even know that. Wait, it’s already free under our insurance?

  • S1AMER

    Most people still don’t know that, if you have health insurance, you have free flu shots. That’s thanks, of course, to the Affordable Care Act’s mandatory free coverage of preventive care measures.

    Too many people, alas, go to the local chain pharmacy or a phasmacy in a grocery shot. Yeah, you can get your shot there, but you’ll have to pay a drug co-pay (assuming you have health insurance that covers drugs).

    (Too many other people, alas, don’t get flu shots. That’s not smart.)

    Anyhow, get thee to your doctor and get your free flu shot! (Possibly avoiding heart attacks is a nice possible plus.)

  • Whitewitch

    If they can’t get you to go for a flu shot to prevent the flu – perhaps they can sell them to us to prevent a heart attack. The bottom line is the most important line.

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