As research suggests that flu can trigger a heart attack, Professor Julian Halcox explains why the flu virus can have such a potentially lethal affect on the body and extols the virtues of vaccination.
INFLUENZA infections are usually unpleasant and debilitating but they should be of particular concern for those with and at risk of heart disease.
Severe, life-threatening complications, such as pneumonia, are well recognised but an increasing body of research suggests that all too often a bout of the flu is complicated by a heart attack.
This is a particularly important consideration at this time of year as we enter the flu season and in light of the swine flu pandemic.
Our outlook can clearly be improved by making sure that those at risk get vaccinated as soon as possible and by all of us following the sensible infection control measures in the Catch It, Bin It, Kill It campaign.
Flu is a serious infection caused by the influenza virus, which is characterised by fevers, aches and pains and often severe upper respiratory symptoms.
The intense inflammation driven by the infection can also have devastating consequences for the heart by significantly increasing the risk of heart attack caused by coronary thrombosis – the formation of a blood clot in one of the arteries that supplies blood to the heart.
This is much more likely to occur in those who already have coronary artery disease or are at increased risk of this condition because they have diabetes, high cholesterol or high blood pressure; they smoke or because they are getting older.
It is these people who have most to gain from vaccination.
A paper that reviewed studies exploring the link between flu and heart attacks was published recently in one of The Lancet journals.
The authors found a several fold increase in the risk of heart attack in those with documented flu or a flu-like illness and also that the death rate from cardiovascular disease in the population increased by up to 50% during influenza epidemics.
The specific impact of swine flu was not examined. They did, however, look at the impact of seasonal flu vaccine in at-risk patients and found that vaccination could potentially halve the risk of cardiovascular death.
However, larger studies are needed to improve the accuracy of this estimate.
Considered in its entirety, this important paper sends out a strong message that we should take flu very seriously and encourage uptake of vaccination by those at increased cardiovascular risk.
The current recommendations are that the seasonal flu vaccine should be given to people over the age of 65 and those with other health conditions that put them at increased risk of complications.
Those at high risk of cardiovascular disease due to a bad risk factor profile could also potentially benefit from vaccination.
It is worrying that less than half of those eligible actually receive the vaccination, usually due to refusal or failure to respond to their invitation to attend for the jab.
Although mild side-effects of the vaccination are common, serious complications are rare and the potential benefit to the high-risk individual and net benefit to the population greatly outweighs the risks of harm.
But what about swine flu and heart disease?
While it is a little early to know whether the risk of heart attack during infection with the H1NI virus is increased to the same extent as with other strains of the influenza virus, it would be unwise to assume that there is no increase in risk.
What does appear to set pandemic swine flu apart from illness caused by the more common seasonal influenza virus is that children appear to be particularly susceptible to more severe infections, whereas the elderly do not appear to be at such high risk.
Importantly, those with underlying health problems, particularly conditions associated with weakened immune systems, do appear to be at increased risk.
The swine flu vaccine is now available – undoubtedly people with, and at high risk of, heart disease should be strongly considered for vaccination.
A recent small study showed that the conventional seasonal flu vaccine appeared to reduce the likelihood of swine flu infection by over a half and also to reduce the risk of death for those becoming infected despite vaccination.
However, infection was still common and the seasonal flu vaccine should not be considered to provide comprehensive cover against swine flu.
Therefore, those at increased risk from both swine flu and seasonal flu should receive both vaccines.
The swine flu vaccine is produced by a similar method to the conventional vaccine and appears to be safe and effective, although we will need to carefully monitor the impact of the vaccination programme and refine our approaches as more information is gathered.
At this time of year, the risk of contracting flu starts to increase dramatically and the sooner those that need these vaccinations receive them the better – ideally before the end of November.
So if you are one of those likely to benefit, do yourself a favour and see your doctor about getting vaccinated.
Professor Julian Halcox is a consultant cardiologist at Cardiff University and the University Hospital of Wales
SOURCE: walesonline
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