While the flu shot can be less effective in older adults, it may protect them from developing an illness severe enough to require hospitalization, according to a new study.
Last year's flu shot reduced the risk of being hospitalized as a result of the flu by about 71 percent in adults of all ages, and 77 percent in people ages 50 and older, the study found.
The findings are "reassuring in light of recent reports that flu vaccination can be less effective in older adults," said study researcher Dr. Keipp Talbot, an infectious disease researcher at Vanderbilt University Medical Center in Nashville.
A report released last month showed that the current flu shot did not do a good job of preventing older adults from catching the flu. Adults ages 65 and over who got the shot were just as likely to visit the doctor for flu symptoms as those who weren't vaccinated.
The importance of the new study is that it suggests that individuals who do get sick develop a less severe illness if they are vaccinated.
"Although flu vaccination can vary in how well it works, it’s still the best tool we have against the flu, and this study shows just how important the flu vaccine can be in preventing severe illness in older adults," said study researcher Dr. Mark Thompson, a flu expert at the Centers for Disease Control and Prevention.
Older adults are at greater risk for hospitalization and death from the flu. Of the 10,721 people hospitalized with flu this season, more than half were ages 65 and over.
Increasing flu vaccination rates in older adults could prevent more than one-third of flu hospitalizations each year, Talbot said.
Regardless of whether or not they've been vaccinated, older adults who develop symptoms of the flu (including fever, cough, body aches, headache, chills and fatigue) should seek medical care right away. Antiviral medications can ease flu symptoms, but they work best if they're given within 48 hours of the onset of symptoms.
Because the new study only looked at hospitalizations for flu in Tennessee, it's not clear if the results translate to the population as a whole, but they are similar to those found in earlier studies.
The new study was published online Feb. 28 in the journal Clinical Infectious Diseases.
Pass it on: Flu vaccination significantly reduces the risk of hospitalization with the flu, especially for older adults.
Live Science newsletter
Stay up to date on the latest science news by signing up for our Essentials newsletter.
Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.