Analysis of research from five published studies shows that patients who received a placebo or no treatment experienced a major cardiovascular problem nearly twice as often as those who got a flu shot.
The combined studies involved 6,000 people, of whom the average age was 67 years old. Around a third of those studied had a history of cardiac problems.
Of those who received flu shots, 95 people -- 2.9 percent -- had a major cardiovascular event in the next year. Among those who did not get the vaccination, 151 people -- 4.7 percent -- had a major cardiovascular problem.
And among those who had already experienced heart problems, the difference was more pronounced. Just one in ten of those treated with the flu vaccine had another cardiac event within a year, compared to nearly one in four of those who did not receive the treatment.
While the study found only that the incidence of cardiovascular problems was associated with getting a flu shot -- not that the flu shot actually caused a reduction in heart problems -- researchers said avoiding the flu was what likely made the biggest difference.
Getting sick could trigger a number of problems in already vulnerable patients, such as the rupture of artery plaques, inflammation of the heart muscle or irregular heartbeat.
As such, the flu vaccination "represents a simple, once-annual protective therapy to reduce cardiovascular events," the researchers wrote in the study, published in the October 23 issue of the Journal of the American Medical Association.
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