Flu Vaccine and Heart Attack Risk

Adults vaccinated for seasonal influenza may be less likely to suffer heart attacks.
Bloomberg News (9/20, Randall) reported that, according to a study published online Sept. 20 in the Canadian Medical Association Journal, "adults vaccinated for seasonal influenza were less likely to suffer heart attacks." After examining "vaccination rates of 16,012 people who had heart attacks and 62,694 patients of similar age and background who didn't," researchers found that "people at least 40 years old who were vaccinated during the flu season showed a 20 percent reduction in first heart attacks within a year, compared with patients who didn't get shots."
"The relationship was stronger if immunization occurred early in the season (before mid-November)," MedPage Today (9/20, Neale) reported. However, the "pneumococcal vaccination did not show the same effect."
HealthDay (9/20, Holohan) reported that the study's findings "drew some criticism from US experts." For instance, "Dr. Kirk Garratt, associate director of the division of cardiac intervention at Lenox Hill Hospital in New York City, said the study found there were 19 percent fewer heart attack patients vaccinated in the previous year, not that there was a 19 percent reduction in heart attacks among the vaccinated." He added that "if getting a flu shot could prevent 19 percent of heart attacks, it would have been noticed before now." Dr. Harlan Krumholz, director of the Yale-New Haven Hospital Center for Outcomes Research and Evaluation at Yale Medical School, observed that "the study's claim of a 19 percent reduction in heart attacks is not justified by the data."
HeartWire (9/20, Nainggolan) reported, "Asked if this could mean that the recommendations for vaccination could change," the study's lead author "said that it's unlikely at the moment, until the reduction in MI with flu vaccine is proven, because 'the risk of heart attack in the population among those aged 40 to 65 is generally low.'" However, were it indeed "proven, it's possible that the advice could be amended to recommend flu vaccination for those aged 40 to 65 who are at high risk of heart attack but not necessarily of flu and who are not covered by the current high-risk categories," such as "those who smoke and/or have high cholesterol, for instance," he explained.