Flu Vaccine Shown to Reduce Mortality, CV Events in Adults with CVD

Influenza vaccination is associated with lower risk for all-cause and cardiovascular death in patients with CVD vs no vaccination, a new meta-analysis found.

Influenza vaccination is associated with lower risk for all-cause and cardiovascular (CV) mortality in patients with cardiovascular disease (CVD) vs no vaccination, according to a new meta-analysis published in the March issue of the Journal of the American Heart Association.

“Influenza is the most common respiratory infection. Yet, only 45% of adults in the United States were vaccinated against influenza during the 2018 to 2019 season despite the available evidence favoring survival benefit in CVD,” wrote authors led by Siva H. Yedlapati, MD, internist, Department of Medicine, Erie County Medical Center, Buffalo, New York.

“Influenza vaccination in patients with or at risk for CVD is a standard of care, and all providers should assume the responsibility of inquiring about vaccination status, providing education, and ensuring that patients have the opportunity to be vaccinated,” continued authors.

Yedlapati and colleagues identified 16 studies (4 randomized; 12 observational) that enrolled a total of 237 058 participants (mean age, 69.2 years; 36.6% women) to assess the effects of the influenza vaccine on mortality and CV outcomes in individuals with CVD.

Approximately 65% of participants had hypertension, 31% had diabetes, and 23% were smokers.

At a median follow-up of 19.5 months, influenza vaccination was associated with a lower risk of all-cause mortality (risk ratio [RR] 0.75; 95% confidence interval [CI], 0.6-0.93; P=0.01), CV mortality (RR 0.82; 95% CI, 0.8–0.84; P<.001), and major adverse CV events (MACE) (RR, 0.87; 95% CI, 0.8–0.94; P<.001) vs control.

Influenza vaccination, however, was not associated with a statistically significant reduction of myocardial infarction (MI) (RR, 0.73; 95% CI, 0.49-1.09; P=0.12) vs control.

“Our meta‐analysis provides further confirmation that preventing influenza infection through vaccination can reduce MACE and mortality risk,” concluded study authors. “Despite lack of statistically significant reduction for MI, the directionality of the effect estimates with numerical 27% RR reduction appears to influence MACE, which consequently resulted in the observed survival benefit with influenza vaccine. However, since these findings do not represent causative effect, these observations should be considered hypothesis‐generating.”