Infectious disease experts are calling on policy makers to consider funding the yearly influenza vaccine to all those aged over 50 to help prevent acute MI.
Professor Raina MacIntyre, a member of the ISG and Professor of Infectious Diseases Epidemiology at UNSW who has been investigating the association said the yearly jab was about 45% effective in preventing heart attack and should be an essential part of CVD prevention and management strategies.”
“A 45% vaccine effectiveness (VE) rate is very high,” she told the limbic.
“Especially when you consider that the heart attack prevention rate for statins or antihypertensives is around 25-35%.”
In a paper published in BMJ Heart, Professor McIntyre, who has previously published two studies investigating the protective affect of the flu vaccine against AMI, said the vaccine’s VE rate was comparable with other accepted routine coronary prevention measures such as smoking cessation (32–43%), statins (19–30%) and antihypertensive therapy (17–25%).
According to Professor McIntyre, while the evidence supporting a role for influenza
vaccine in coronary prevention is substantial, rates of influenza vaccination in patients with heart diseases are low – a factor that may, at least in part, be due to the fact that its recommendation in this group is seen as one that aims to prevent influenza rather than to reduce the risk of AMI, she suggested.
“Only about 30% of people under 65 with heart disease actually get vaccinated so the question is, can we improve the uptake so we have more people protected against AMI – should we be looking at funding it universally on an age recommendation from 50 and older?”
“We need a paradigm shift to encourage clinicians to see influenza vaccine as a cheap, safe and effective additional prevention strategy for patients with CHD.”
In a 2013 case controlled study of 275 patients over the age of 40 admitted to a Sydney hospital for MI and who had nose and throat swabs taken on admission Professor McIntyre and colleagues reported that around one in eight (12.4%; 34) had recently had flu, compared with just under 7% (18) in the comparison group of 284 patients admitted to the same hospital at the same time but who had not suffered MI. Half of all the patients had had the flu jab that year.
“The first interesting thing we found is that almost 10% of patients coming in with a heart attack actually had flu that hadn’t been diagnosed,” Professor McIntyre said adding that the finding indicated influenza as an undiagnosed potential precipitation of AMI.
A recent respiratory infection was more common among those patients who had had a heart attack and doubled the risk. After taking other influential factors into account, such as age, high cholesterol, and smoking, flu did not increase heart attack risk. But vaccination against the infection did seem to be protective, decreasing the risk of a heart attack by 45%.
“We do very well in asking patients to take statins to lower their cholesterol or to [adopt] lifestyle measures to reduce their blood pressure … if we start thinking of flu vaccination as another tool in the armoury that we can use to prevent heart disease – if we get that thinking changed –then I think we can take that step to improving outcomes for people at risk of CVD.