Fort Worth, Texas ? For years, senior citizens have been told to get a flu shot even though the vaccine is often considered less effective in those older than 65.

A study in today’s New England Journal of Medicine revealed that flu shots are not only effective for the elderly, but that the older a person is, the greater the benefits. With each decade of life, it appears that the vaccine reduces the risk of hospitalization and death, said Dr. R. Doug Hardy, an infectious disease specialist at UT Southwestern Medical Center in Dallas.

“The influenza vaccine does work and we shouldn’t be downplaying its importance,” he said.

The decadelong study looked at more than 700,000 adults, and found that getting a flu shot each year decreased the rate of hospitalizations and greatly decreased the risk of death, Hardy said.

The study disputes reports that question the effectiveness of the shot in older adults.

One reason the vaccine might not be as effective among the elderly is the immune system gets weaker with age, health officials said. Still, the Centers for Disease Control and Prevention has recommended flu shots for older adults, who face a greater risk of serious complications. About 90 percent of the estimated 36,000 Americans who die annually from the flu are 65 and older, according to the CDC.

Complications from the flu, such as pneumonia, can lead to respiratory failure, said Dr. Susan Conroy, a Fort Worth internist and assistant professor at the UNT Health Science Center. Inpatient care also puts people at risk for a hospital-acquired infections.