The flu vaccine substantially lowers the risk of fatal and non-fatal cardiovascular events, according to new research.
The flu shot should be recommended for patients with underlying heart problems, with new research showing that getting the vaccine significantly reduces the risk of heart attack and stroke.
A recent meta-analysis of seven studies, published in JAMA Network, found that participants who were vaccinated against the flu were more than 30% less likely to experience severe heart problems compared with those who weren’t vaccinated.
If high-risk participants with recent acute coronary syndrome (ACS) received the vaccine, their risk of heart attack or stroke was almost halved.
“Given influenza poses a threat to population health during the Covid-19 pandemic, it is integral to counsel high-risk patients on the cardiovascular benefits of influenza vaccination,” the Canadian researchers said.
The study combined a prior meta-analysis of six randomised control trials from the past two decades with results from a cardiovascular outcome trial published last year.
The meta-analysis revealed that the flu vaccine significantly reduced the risk of suffering a cardiovascular event within the space of a year. For patients with ACS, the reduction in this risk was even greater.
The meta-analysis revealed that across all six trials, 95 of the 3228 patients treated with the flu vaccine developed a major adverse cardiovascular event within a year compared with 151 of 3231 patients who developed a major adverse cardiovascular event in the placebo and control groups.
The authors also conducted a subgroup analysis of three trials involving patients with coronary artery disease (CAD). In these trials, among the 789 patients with a history of recent ACS, 10.25% of those who got the flu shot suffered a major adverse cardiovascular event compared with 23.1% in the placebo and control groups.
This revealed a much greater risk reduction than for patients with stable CAD. Among these patients, 6.9% of those who received the flu vaccine suffered a major adverse cardiovascular event compared with 7.4% of those in placebo and control groups.
The researchers also pointed to a 2013 meta-analysis, published in the JAMA Network, which also examined the link between the flu vaccine and prevention of cardiovascular events.
“Although acute influenza infection is an independent risk factor for fatal and nonfatal cardiovascular events, the mechanism underlying that risk is less clear, but may relate to triggering the rupture of a vulnerable atherosclerotic plaque, fluid overload heart failure, myocarditis, arrhythmia or the susceptibility of a frail and vulnerable patient,” the researchers wrote.
“Influenza vaccination may prevent cardiovascular events via avoidance of atherosclerotic plaque rupture or other forms of cardiac injury in a vulnerable patient and represents a simple once-annual protective therapy to reduce cardiovascular events.”
Since flu infection is linked to higher chances of hospitalisation and death due to heart problems, the study’s authors hope their findings will help raise awareness among clinicians and policy makers about the cardiovascular benefits of getting the flu vaccine.
