Flu Shot Linked to 85 Percent Lower Risk of Cardiac Arrest in Following Year Among Over 50s

Getting the flu vaccine does not only protect against the respiratory disease, but may also prevent those at risk of experiencing complications from heart problems, according to a study.

Researchers studied data from 2014 on 7,056,314 hospital patients in the U.S. who were at high risk of having complications from the flu, and looked at how many were vaccinated against the disease during their stay. The at-risk participants included adults aged 50 years old and over, people with chronic health conditions, AIDS patients, those living in nursing facilities, obese people, as well as American Indians and Alaskan natives.

Getting vaccinated was linked to better health in the following year in the study. Participants aged 50 plus who got the shot were 85 percent less likely to have a cardiac arrest, and 73 percent less likely to die. Their chance of having a transient ischemic attack, which is similar to a stroke, was 47 percent lower, and their risk of a heart attack 28 percent.

However, the data revealed only 168,325 patients had their flu shot while they were hospitalized. The researchers highlighted that those aged 50 and over were less likely to be vaccinated compared with the general population, at 1.8 percent versus 15.3 percent. For HIV/AIDS patients, the vaccination rate was 2 percent compared with 8 percent of those without the disease; and 1.8 percent versus 9.5 percent for nursing home residents and those living independently. Some 2.4 percent of obese patients were vaccinated, compared with 9 percent of those of a healthy weight.

The research was presented as an abstract at the virtual American Heart Association's Basic Cardiovascular Sciences 2020 Scientific Sessions. A spokesperson for the American Heart Association told Newsweek the abstracts go through a volunteer peer review process to be accepted for the meeting.

Lead author Roshni A. Mandania, a medical student at Texas Tech University Health Sciences Center Paul L. Foster School of Medicine in El Paso, said in a statement: "These groups should have the highest vaccination rates because they are the most at risk; however, our findings show the opposite—flu vaccinations are under-utilized.

"As health care providers, we must do everything we can to ensure our most vulnerable populations are protected against the flu and its serious complications."

Barry A. Franklin, a fellow with the American Heart Association and professor of internal medicine at Oakland University William Beaumont School of Medicine, who was not involved in the research, told Newsweek via email the results are not particularly unique or new. He pointed to a 2013 study published in the JAMA linking the flu vaccine with a decreased risk of what are known as cardiac events the following year.

"Thus, the higher risk patients, that is, those with known cardiovascular disease, demonstrated the greatest benefit from the flu shot—like these results."

Niro Siriwardena, professor of primary and prehospital health care at the U.K.'s University of Lincoln, who did not work on the paper, told Newsweek the study was limited because its methods meant the team for the flu shot was linked with a reduction in heart problems, "but we can't say [the] flu vaccine protects against heart disease."

There may be alternative explanations other than the flu vaccination for the results, according to Siriwardena. People who adopt healthier lifestyles—for instance by eating well, exercising, and not smoking—may be more likely to receive treatments to prevent cardiovascular disease and also tend to be more likely to ask for and have flu vaccination.

Siriwardena said the important take-away from the study is that people at risk of flu complications should get vaccinated, including people with heart, lung, kidney disease, diabetes, immune problems, those in care facilities, older people, and children who might spread flu to older family members.

"[The] flu vaccine has benefits in younger people but is often not recommended as a public health measure in younger adults because it is considered less cost-effective."

Siriwardena said: "As far as we know, the benefits during the COVID-19 pandemic will be the same, but flu vaccination could be important in reducing hospitalization where hospital and intensive care beds might be under pressure during the pandemic."

Senior cardiac nurse at the U.K.-based charity the British Heart Foundation Philippa Hobson, who was also not involved in the study, told Newsweek: "We know that people who have a history of heart and circulatory illnesses are at an increased risk of developing a bad flu, which could lead to serious complications.

"If you have had a heart attack, the flu puts you at a greater risk of having another one. The virus can also weaken the respiratory system, which the heart relies on, as well as directly harming the heart muscle—so it is important you take all safety precautions if you are at a heightened risk of the virus.

"We would urge everybody living with heart and circulatory conditions to get a flu jab this year—it could save your life."

The study is the latest to find potential benefits of having the flu shot aside from protecting against the disease. According to a study presented at the virtual Alzheimer's Association International Conference taking place between July 27 to 31, the flu vaccine may also protect against Alzheimer's disease.

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A stock image shows a doctor checking a man's chest. Scientists have explored the benefits of the flu vaccine in relation to heart problems. Getty