New European research has found that individuals with high blood pressure could lower their risk of death during flu season by getting the influenza vaccine.
Carried out by researchers at the University of Copenhagen, Denmark, the new study looked at 608,452 patients aged 18 to 100 years with hypertension (high blood pressure) during nine consecutive flu seasons.
The researchers recorded how many patients had received a flu vaccine before the start of each flu season and then followed them through the season, noting how many died from all causes, from any cardiovascular cause, and from heart attack or stroke.
The findings, presented on Sunday at ESC (European Society of Cardiology) Congress 2019 together with the World Congress of Cardiology, showed that after taking into account potentially influencing factors such as age, medications, and socioeconomic status, high blood pressure patients who received the flu vaccine appeared to benefit from an 18 percent reduced risk of death from all causes during flu season.
In addition, those who received the vaccine had a 16 percent reduced risk of death from any cardiovascular cause, and a 10 percent reduced risk of dying from heart attack or stroke.
"Given these results, it is my belief that all patients with high blood pressure should have an annual flu vaccination," commented first author Daniel Modin. "Vaccination is safe, cheap, readily available, and decreases influenza infection. On top of that, our study suggests that it could also protect against fatal heart attacks and strokes, and deaths from other causes."
Previous research has suggested that the stress the flu infection puts on the body could trigger heart attacks and strokes, with Modin adding that the strong immune response to the infection can also cause inflammation which could lead to heart attacks and strokes.
"Heart attacks and strokes are caused by the rupture of atherosclerotic plaques in the arteries leading to the heart or the brain. After a rupture, a blood clot forms and cuts off the blood supply. It is thought that the high levels of acute inflammation induced by influenza infection reduce the stability of plaques and make them more likely to rupture," explained Modin.
Those with high blood pressure already have a higher risk of heart attack and stroke, and so preventing a flu infection through vaccination may help to protect against cardiovascular events.
"We show that influenza vaccination may improve cardiovascular outcomes in patients with hypertension. During the nine flu seasons we studied, vaccine coverage ranged from 26 percent to 36 percent, meaning that many patients with high blood pressure were not vaccinated. If you have high blood pressure, it would be worth discussing vaccination with your doctor," advised Modin.