People battling heart failure should make the time to get their flu shots now, a new study suggests.
Not only will the shots help prevent influenza in this high-risk group, but it could also reduce pneumonia infections and cardiac complications, researchers report.
"If you have heart failure, you should get your flu shot because it can save your life -- that is what we found in this study," said lead investigator Dr. Mark Loeb, a professor of pathology and molecular medicine at McMaster University in Ontario, Canada. "It is underappreciated that influenza vaccine can save people from cardiovascular death."
In the study, investigators from McMaster, the Population Health Research Institute of McMaster (PHRI) and Hamilton Health Sciences tracked more than 5,000 patients with heart failure in 10 countries across Africa, Asia and the Middle East. Few people in these areas get regular flu shots.
The patients received either an influenza vaccine or a placebo annually between June 2015 and November 2021.
Over a year, influenza vaccines reduced pneumonia by 40% and hospitalizations in patients with heart failure by 15%, according to the study. During the fall and winter flu season, it reduced deaths by 20%.
People with heart failure are already vulnerable to poor health outcomes, with a 50% chance of dying within five years, Loeb said. About 20% are hospitalized for cardiovascular complications every year.
"Importantly, we looked at low- and middle-income countries, where 80% of cardiovascular disease occurs and where flu vaccination rates are low," Loeb said in a university news release.
The study is the first clinical trial of the flu vaccine's effectiveness in patients with heart failure.
"The flu shot should be part of the standard practice in people with heart failure, given how simple, inexpensive and safe it is. Avoiding one-sixth of deaths from heart disease and preventing hospitalizations makes it very cost-effective and that can have an important public health and clinical impact," said study co-author Dr. Salim Yusuf, executive director of PHRI.
The international study was published in the December 2022 issue of The Lancet Global Health.
The American Heart Association has more on heart failure.
SOURCE: McMaster University, news release, Nov. 15, 2022