Study: Only half of Americans with a history of heart disease get annual flu shot

Reviewed by Emily Henderson, B.Sc.May 5 2021

People with heart disease are more likely to become seriously ill from the flu and other respiratory illnesses, including the coronavirus. Yet, new research finds that only half of Americans with a history of heart disease or stroke report getting an annual flu shot, despite widespread recommendations to do so. Rates of vaccination were even lower among Blacks and Hispanics, according to data being presented at the American College of Cardiology's 70^th Annual Scientific Session.

Researchers say the findings should renew efforts to assure flu vaccination is a routine part of quality cardiovascular care.

As a nation, the U.S. health care system must do a better job protecting a population that is at very high risk for serious complications and death from the flu. As physicians, it is our job to help patients take these simple but effective preventative measures as well as to determine what the barriers to vaccination are, so we can help our patients get around them."

Varayini Pankayatselvan, MD, Internal Medicine Resident at Beth Israel Deaconess Medical Center in Boston and Study's Lead Author

The study, which used data from the 2018-2019 Behavioral Risk Factor Surveillance System survey conducted by the Centers for Disease Control and Prevention, provides the first real-world look at national flu vaccination patterns in adults with cardiovascular disease. Pankayatselvan said earlier studies in this area have been limited to inpatient samples from hospitalized patients.

A total of 101,210 respondents with a physician diagnosis of heart attack, coronary heart disease or stroke were included in the analysis. They were asked if they got a flu shot "within the past year." Only 50.4% of this population reported being up to date with flu vaccination, which is strikingly low given that the ACC and other leading health organizations strongly recommend that anyone with cardiovascular disease get a flu shot every year.

Key findings showed no difference in vaccination rates between women and men. People who went to college were more likely to have received a flu shot within the past year when compared with those who had less education. Black and Hispanic adults were about 20% less likely to report getting a flu vaccine compared with whites.

"We haven't made much progress when it comes to closing persistent vaccination gaps among racial and ethnic groups, and preliminary data on the COVID-19 vaccination also points to disparities still being an issue, which is concerning," Pankayatselvan said, adding that people with cardiovascular disease are also being urged to get the COVID-19 vaccine. "We need more research to better understand vaccine reluctance, inequities in access to vaccines as well as the value of seeking out community partnerships to improve vaccinations across the board."

Patients with chronic obstructive pulmonary disease, chronic kidney disease and diabetes were significantly more likely to have gotten a flu shot. Pankayatselvan said this suggests these patients may have more routine access to providers who administer the flu vaccine in their office; she said earlier studies have shown that compared with pulmonary and endocrinology practices, cardiology offices are much less likely to have the flu vaccine on-site. Additionally, when people think of the flu or COVID-19, they more readily think of lung issues, even though these infections can cause heart troubles too. These infections can place added stress on the body and heart by quickening heart rate, ramping up the body's fight or flight response and triggering inflammation.

What is Pankayatselvan's message to people with heart disease? "Next time you see a doctor--any doctor--ask about getting your flu shot. Your physician can answer any questions you have and help you make a plan to get it every year," she said. "It's an easy, fast and safe way to prevent a lot of potential complications including severe illness, pneumonia, heart attacks, heart failure, hospitalization and even death."

There are other benefits too, Pankayatselvan said. "Even flu aside, we know that getting the flu shot may be a cardioprotective measure for hospitalized patients with influenza. Previous research has shown that, among hospitalized patients with influenza, the flu vaccine is linked to a lower risk of acute heart failure and acute ischemic heart disease. Additionally, some research indicates the protective effect of getting the flu vaccine may be similar to smoking cessation and some heart medications," she said.

Getting a flu shot also prevents people from transmitting the flu to others, something researchers are hoping will prove true for the COVID-19 vaccine too.

This study is limited in that it relies on people's recollection of getting a flu shot. It also only gives a snapshot of vaccination patterns in 2018-2019; it remains to be seen whether the threat of COVID-19 may have prompted more people with heart disease to get vaccinated against the flu.