Flu can trigger a heart attack, Dutch study suggests

Individuals diagnosed with flu are six times more likely to have a heart attack in the week after testing positive for the virus, according to a Dutch study published in The New England Journal of Medicine (NEJM) and being presented at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID 2023, Copenhagen, 15-18 April), underline the importance of vaccination and awareness of heart attack symptoms among flu patients and those treating them.

The study used results from 16 laboratories across the Netherlands and death and hospital records to produce a more complete picture. Of the 419 heart attacks, 25 were in the first seven days after flu diagnosis, 217 within the year before diagnosis and 177 in the year after flu diagnosis (not including the first seven days). Around a third of the individuals (139/401) died, of any cause, within a year of being diagnosed with flu. 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 than in the year before or after.

The influenza virus is known to increase the coagulation of blood and 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. The researchers recommend strategies to prevent influenza infection, including vaccination, as well as advocating for a raised awareness among physicians and hospitalized flu patients for symptoms of heart attacks.