Flu Shot May Guard Against Irregular Heart Rate: Study

WEDNESDAY, Feb. 10, 2016 (HealthDay News) — Along with reducing your flu risk, a flu shot may protect you from a common heart rhythm disorder that significantly increases stroke risk, researchers report.

Their study of about 57,000 people in Taiwan found a significant association between the flu and new cases of atrial fibrillation, a condition that causes an irregular and often abnormally fast heart rate. The condition has been linked to a fivefold increased risk of stroke, according to researchers.

Among people who had not received a flu shot, those who got the flu were 18 percent more likely to develop atrial fibrillation than those who did not get the flu. The risk among vaccinated people who got the flu was about the same as unvaccinated people who did not get the flu, the study authors said.

Flu vaccination was consistently associated with a lower risk of atrial fibrillation (AF) in different groups of patients, according to the study published online recently in the journal HeartRhythm.

“According to the findings presented here, the possibility of AF should be kept in mind when patients with influenza infection complain of palpitations or experience ischemic stroke,” lead investigators Dr. Tze-Fan Chao and Dr. Su-Jung Chen, of Taipei Veterans General Hospital, and colleagues wrote.

“Influenza vaccination should be encouraged for patients, especially those who have a high risk of atrial fibrillation, to try to prevent the occurrence of atrial fibrillation and subsequent stroke. However, a further prospective study is necessary to confirm our findings,” they added.

In an accompanying editorial, two cardiologists from Northwestern University in Chicago said the study suggests the flu vaccine has broader potential public health benefits.

“The results of this study beg the question as to whether the acute treatment of the influenza infection itself, or addressing the inflammatory response associated with infection, may help prevent secondary episodes of AF,” Dr. Nishant Verma and Dr. Bradley Knight wrote. “Beyond the prospective trial mentioned by the authors, we look forward to future studies into these and other areas that may help confirm and validate the observed findings.”

More information

The U.S. National Heart, Lung, and Blood Institute has more about atrial fibrillation.