Fully 47% of adults age 65 and older are at high risk for serious flu complications, according to U.S. health officials. Those with heart disease and other chronic conditions are the most vulnerable.

In the 2018-2019 flu season, 93% of adults hospitalized for flu complications had an underlying condition, said William Borden, M.D., a population health officer at George Washington University. In those cases, the most common underlying conditions were cardiovascular disease and metabolic disorders like diabetes, obesity and chronic lung disease, he said during a National Foundation for Infectious Diseases news conference last week.

“Unfortunately flu infection is often just the beginning of the problem for certain patients with chronic health conditions,” Borden said. “An often unrecognized danger of the flu is that the resulting inflammation may last for several weeks after the acute infection.”

That inflammation can worsen the underlying disease, leading to events like heart attack and stroke, he added.

An annual flu vaccination offers significant protection against these risks, Borden said. One study he referenced demonstrated that flu vaccines are just as effective in protecting people with heart disease as smoking cessation and taking statins. In another study, flu vaccination reduced the risk of cardiovascular events by 53% among people who’ve had a heart attack in the last year.

It’s also been shown that flu vaccination protects people with lung disease and diabetes, Borden added. “This includes improving COPD exacerbations, admission rates for stroke, heart failure and other causes of death in people with type 2 diabetes.”

Additional stats relayed at the NFID conference include:

  • People with heart disease are six times more likely than people without the condition to have a heart attack within the first week of flu infection.
  • People with diabetes are three times more likely to die of flu complications than their peers without diabetes.

A video of the NFID news conference has been posted online.