Flu Vaccine Could Potentially Be Prescribed to Prevent Dementia

Patients with heart failure who have had 3 or more vaccines had a 55% decreased risk of developing dementia.

Findings from a recent study suggest the influenza vaccine is associated with a decreased risk of dementia in patients with heart failure.

"Previous studies have shown that there is link between impairment in cognitive function and heart failure," said Ju-Chi Liu, MD, PhD. "Some reports have also suggested that inflammation after getting the flu might contribute to dementia. However, there are no solid data to demonstrate that influenza vaccination could decrease the relative risk of dementia in patients with heart failure."

The study, presented at Heart Failure 2016 and the 3rd World Congress on Acute Heart Failure, included 20,509 patients over 60-years-old diagnosed with heart failure from 2000 to 2012 from the National Health Insurance Research Dataset.

Of the patients, 10,797 had at least 1 influenza vaccination and 9712 were not vaccinated during the 12-year follow-up, according to the study.

Researchers found that patients who received the vaccine had a 35% decreased risk of developing dementia compared with patients who were not vaccinated. Patients who received 3 or more influenza vaccinations had a 55% decreased risk.

“We think that the flu virus can activate the immune response and cause inflammation which may injure the brain cells," Dr Liu said. "Respiratory infection during flu can induce changes in blood pressure and heart rate, referred to as an unstable haemodynamic status, which may also harm the brain tissue."

Researchers believe this effect could impact the development of dementia, especially in patients with heart failure since they have impaired circulation in the brain already, according to the study.

"Vaccination reduces the chance of getting the flu, which means that the associated immune activation, inflammation and unstable haemodynamic status do not occur,” Dr Liu said. “This could explain the reduced risk of developing dementia. The more vaccinations patients received, the less chance they had of getting the flu, which might be why they had an even lower risk of dementia."

Researchers also discovered that patients who received the vaccine and were over 70-years-old had a 44% decreased risk of dementia and a 26% decreased risk if they were 60- to 69-years-old. Researchers also found that vaccinated male patients had a 40% decreased risk of dementia, and women only had a 31% decreased risk.

Their findings suggest the influenza vaccine could potentially decrease the risk of dementia, as well as reducing the risk of respiratory infection and death from pneumonia.

"If influenza vaccination can prevent the inflammation induced by flu, it may decrease the risk of dementia in heart failure patients. This is an important prospect for dementia prevention,” Dr Liu concluded. “More efforts are needed to ensure that patients with heart failure are vaccinated against influenza every year. Our data suggests that these patients benefit even more from vaccination than was previously thought."