PEOPLE with a flu infection are six times more likely to suffer a heart attack in the week after they test positive for the virus than they are in the year before or afterwards, according to new research.

The findings, from a Dutch study, will be presented at the annual European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Copenhagen next month. 

The conference will be held from April 15 to 18. 


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It comes after Scotland experienced its worst winter flu season in around a decade in December, when confirmed diagnoses and hospitalisations for the virus soared following a lull during the pandemic. 

The Herald: Flu rates in Scotland surged to 'extraordinary' levels in DecemberFlu rates in Scotland surged to 'extraordinary' levels in December (Image: PHS)

The link between flu and heart attacks has been made before, in a 2018 Canadian study of individuals hospitalised for heart attacks. 

The Canadian study, however, did not include information from death records which meant out-of-hospital deaths from heart attacks were not included.

READ MORE: Male heart deaths in Scotland at highest number in a decade 

Dr Annemarijn de Boer, an expert in primary care at UMC Utrecht, used the results of tests from 16 laboratories across The Netherlands - covering around 40 per cent of the Dutch population - along with death and hospital records to produce a more complete picture.

She identified 26,221 cases of influenza confirmed by laboratories between 2008 and 2019.

Of these patients, 401 had or went on to suffer at least one heart attack (myocardial infarction) within one year of their flu diagnosis - before or after - with 419 heart attacks recorded in total.

READ MORE: Are Scotland's excess deaths really soaring after Covid? 

Of these, 25 occurred in the first seven days after a flu diagnosis.

Compared to the heart attack incidence before and after, the researchers calculated that the individuals studied were 6.16 times more likely to have a heart attack in the seven days following a flu diagnosis.

The influenza virus is known to increase the coagulation, or “stickiness”, of blood.

Similar patterns have been seen with Covid, which is also associated with an increased risk of strokes and heart attacks post-infection.

READ MORE: Scotland's flu deaths highest in 20 years 

It is thought that this, along with the inflammation that is part of the body’s immune response against the virus, can weaken fatty plaques that have built up in the arteries.

If a plaque ruptures, a blood clot can form, blocking the blood supply to the heart and causing a heart attack.

Dr de Boer concludes: “With the potential public health implications of an association between influenza virus infection and acute heart attacks, showing robustness of results in a different study population is important.

“Our results endorse strategies to prevent influenza infection, including vaccination.

"They also advocate for a raised awareness among physicians and hospitalised flu-patients for symptoms of heart attacks.

“While it isn’t clear from our results if those with less severe flu are also at risk, it is prudent for them to be aware of the link.”