Can Flu Shots Help Hearts?

Fewer cardiovascular events and deaths occurred among individuals getting flu shot

(RxWiki News) Getting a jab for the flu might do more than protect you from coming down with it. It might actually lower your risk of a heart attack. Two recent studies have found a possible benefit for your heart from the flu vaccine.

One study showed fewer heart attacks and deaths in vaccinated individuals. The other showed less treatment was needed for irregular heartbeats in vaccinated patients.

The researchers found that individuals who received the flu vaccine were half as likely to have a cardiovascular event as those who did not, regardless of whether the person already had heart disease or not.

"Ask your doctor about the flu vaccine."

Both studies were presented at a recent conference and are not yet published, though one is a review of published research.

The first study, led by Jacob Udell, a cardiologist at Women's College Hospital and the University of Toronto, involved reviewing all the randomized controlled trials involving the flu vaccine that compared people with and without cardiovascular disease.

The four studies identified included 3,227 patents total, about half of which (1,580) did not have cardiovascular syndrome. Among the other half, 796 had post-acute coronary syndrome and 851 had stable heart disease.

After a year, there had been 187 major cardiovascular events, including 65 deaths related to heart problems.

Those vaccinated against the flu were less likely to die from all causes.

In another study, led by Ramanan Kumareswaran of the Sunnybrook Health Sciences Center in Toronto, looked at 229 Sunnybrook patients who had implantable cardiac defibrillators (ICDs).

ICDs are small devices put on a person's chest or abdomen to help with irregular heartbeats by sending electrical pulses to the person's heart.

Of these patients, 179 of them (78 percent) received the flu shot the year before.

Over the following year, 39 of the overall patients needed at least one ICD therapy, which included 10.6 percent of those who had gotten the flu shot and 13.7 percent of those who did not get a flu shot.

The rate of ICD therapies per person was also lower during flu season among those who had the shot compared to those who didn't. The rate was 0.14 therapies per person among vaccinated patients, compared to 0.45 among those who didn't get the flu vaccine.

The authors concluded that the flu vaccine might be linked to needing a lower number of ICD therapies during flu season.

In the second study, the people who chose to get a flu vaccine might have made other lifestyle choices that made them healthier.

However, the first study involved randomizing individuals so that half received the flu vaccine and half received a placebo, so a bias of having vaccinated people with healthier habits would not be possible.

Neither study has been published in a peer-reviewed journal yet, so these findings should be regarded as preliminary. However, the four studies reviewed in Dr. Udell's work were published in peer-reviewed journals.

The studies were both presented October 28 at the Canadian Cardiovascular Congress. Information was unavailable on funding for both. The authors of Dr. Udell's study declared no disclosures.

Review Date: 
November 6, 2012