The flu shot is good for your heart, studies say

Getting inoculated against influenza has been shown to reduce the risk of suffering a serious or fatal cardiac event.

Dave Yasvinski 4 minute read October 18, 2021

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The majority of adults on both sides of the border — including those with high-risk health conditions — continue to avoid getting inoculated against the flu despite evidence the vaccine substantially reduces the risk of suffering a serious or fatal cardiac event.

The analysis, published in the Journal of the American Heart Association, found that less than 50 per cent of American adults with heart disease below the age of 65 get the seasonal shot even though studies show cardiovascular events and influenza epidemics spike at around the same time.

Canadians didn’t fare any better, with just 42 per cent of adults receiving the vaccine during the 2019 to 2020 influenza season, according to a survey by the Public Health Agency of Canada — a number in line with previous seasons. Only 44 per cent of Canadians with chronic health conditions rolled up their sleeves, far short of the national goal of 80 per cent. Seniors were the most likely group to get inoculated, with 70 per cent deciding to do so.

“It seems that younger Americans with high-risk conditions have not gotten the same memo that their older counterparts have received about the importance of getting the influenza vaccine,” said Priyanka Bhugra, lead author of the analysis and an internal medicine specialist at Houston Methodist Hospital. “That’s dangerous, considering people with heart conditions are particularly vulnerable to influenza-related heart complications, whether they’ve reached retirement age or not.”

While most people are aware of the toll the flu can take on the respiratory system in the form of pneumonia, bronchitis and bacterial lung infections, not many realize the harm that can be dealt to the heart as the body tries to stave off an intruder. As white blood cells flood an area in response to a virus, bacteria or infection, parts of the body experience inflammation, tenderness, weakness and pain. This increased activity produces bottlenecks in the vascular system that can lead to blood clots, hypertension and even scarring or swelling of the heart.

It seems that younger Americans with high-risk conditions have not gotten the same memo that their older counterparts have received about the importance of getting the influenza vaccine

Any plaque present in the arteries becomes more likely to rupture under this pressure, causing blockages in the flow of oxygen to the heart that can cause a stroke or attack in an organ that may already be weakened by disease in some patients.

In one study included in the analysis, 11.5 per cent of 336,000 people admitted to the hospital for the flu also experienced a cardiac event. Another study involving 900,000 lab-confirmed flu cases found a similar 11.7 per cent of patients suffered an acute cardiovascular event.

The flu vaccine prevents infection from the constantly mutating virus, on average, 40 per cent of the time. While this number pales in comparison to the efficacy of the COVID-19 vaccines, it significantly lowers the risk of severe illness in the majority of people. In addition to protecting the most vulnerable groups from a serious case of the flu, recent study has shown the vaccine is also protective against cardiovascular mortality.

In one study, vaccinated adults were 37 per cent less likely to require hospitalization for the flu and 82 per cent less likely to require ICU care. Vaccinated patients also spent an average of four fewer days in the ICU than unvaccinated patients and inoculation was related to a lower risk of suffering a cardiovascular event. The vaccine produced consistently better outcomes among high-risk patients with active heart disease to the point the Centers for Disease Control and Prevention strongly recommends that patients with cardiovascular disease get the shot every year.

The researchers are calling on clinicians to do everything in their power to ensure high uptake of inoculation, particularly in patients with underlying chronic conditions. In addition to getting vaccinated as early as possible, patients with heart concerns are encouraged to take their medications regularly and follow their recommended diet, exercise and stress-reduction plans — now more than ever.

“In the context of the ongoing health crisis attributable to the COVID‐19 pandemic, increasing uptake of the influenza vaccine is even more crucial in preventing a concurrent epidemic,” the analysis concludes. “Lessons learned from enhanced influenza vaccine uptake in patients with (cardiovascular disease) will most likely inform vaccination efforts against COVID‐19 once vaccines become more widely available and accessible.”

Dave Yasvinski is a writer with