Flu can increase the risk of having a heart attack by six times within the space of a week, research has shown.
The study, involving thousands of flu cases, provides strong evidence of a link between influenza and heart attacks.
Scientists said the findings, published in the New England Journal of Medicine, reinforced the need for people at risk of heart attacks to have flu jabs.
The Canadian team looked at almost 20,000 cases of laboratory-confirmed flu infection from 2009 to 2014.
Of these patients, 332 were hospitalised for a heart attack within one year of a laboratory-confirmed influenza diagnosis.
The results showed that for seven days after flu was detected, there was a six-fold increase in the chances of patients suffering heart attacks.
Lead scientist Dr Jeff Kwong, from the Institute for Clinical Evaluative Sciences (Ices) in Ontario, said: “Our findings, combined with previous evidence that influenza vaccination reduces cardiovascular events and mortality, support international guidelines that advocate for influenza immunisation in those at high risk of a heart attack.”
The risk may be higher for older adults, patients with influenza B infections, and those experiencing their first heart attack, the researchers said.
A raised, but less extreme, risk of heart attack was also associated with other respiratory viral infections besides influenza.
Dr Kwong added: “People at risk of heart disease should take precautions to prevent respiratory infections, and especially influenza, through measures including vaccinations and hand washing.” – Press Association
