Flu Shots Cut Some Cardiac Complications in Patients With Heart Failure

WEDNESDAY, Nov. 23, 2022 (HealthDay News) -- Flu shots reduce some cardiac complications among people living with heart failure, according to a study published in the December issue of The Lancet Global Health.

Mark Loeb, M.D., from McMaster University in Hamilton, Ontario, Canada, and colleagues assessed whether influenza vaccination reduces death and vascular events in patients with heart failure. The multicenter, international trial randomly assigned 5,129 adults with heart failure to 0.5 mL intramuscularly once a year for up to three years of either an inactivated standard-dose influenza vaccine or saline placebo.

The researchers found that the coprimary outcome of first-event composite for cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke did not differ between the groups (hazard ratio [HR], 0.93; 95 percent confidence interval [CI], 0.81 to 1.07; P = 0.30). The second coprimary outcome of recurrent-events composite for cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and hospitalization for heart failure was also similar between the groups (HR, 0.92; 95 percent CI, 0.84 to 1.02; P = 0.12). The vaccine group had significantly lower rates of secondary outcomes, including all-cause hospitalizations (HR, 0.84; 95 percent CI, 0.74 to 0.97; P = 0.013) and pneumonia (HR, 0.58; 95 percent CI, 0.42 to 0.80; P = 0.0006) versus the placebo group. The groups were similar with respect to all-cause death, cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, and hospitalization for heart failure.

"Although the prespecified coprimary outcomes during the entire period of observation were not statistically significant, the reduction during the peak influenza circulating period suggests that there is likely to be a clinical benefit of giving influenza vaccine, given the clear reduction in pneumonia, a moderate reduction in hospitalizations, and a reduction in cardiovascular events and deaths during periods of peak circulation of influenza," the authors write.

Two authors disclosed financial ties to the pharmaceutical industry.

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