For people with heart failure, getting a seasonal influenza (flu) vaccine was associated with a 50 percent drop in the risk of death during flu season and a 20 percent drop in the risk of death during the rest of the year, according to research presented at the American College of Cardiology’s Annual Scientific Session. The study came out amid the 2017-2018 flu season that brought higher than normal rates of infection and death.

Influenza and flu-related complications can cause death even in otherwise healthy people. Previous research has found the risk of flu-related death is elevated in people with heart failure, a condition in which the heart becomes too weak to pump enough blood to meet the body’s needs. About 6.5 million U.S. adults have heart failure and are susceptible to influenza-related complications including the worsening of dangerous heart failure and secondary infections such as pneumonia.