Flu shots give MI patients
something to celebrate

Cardiovascular death rates reduced by 50% in myocardial infarction patients after vaccination

By Maria Turner

Myocardial infraction(MI) patients who have received the flu vaccine are at a significantly lower risk of cardiovascular death after one year. So say the latest results of the Flu Vaccination in Acute Coronary Syndrome (FLUVACS) study. Earlier reports had shown the shot reduces the risk of death and major cardiac events in the short term.

"There was a 50% reduction in death. This completely shocked us," said lead author, Dr Enrique Gurfinkel, about the one-year results of the FLUVACS study, published in the January issue of the European Heart Journal. Dr Gurfinkel and his colleagues from the Favaloro Foundation in Buenos Aires, Argentina, previously showed that the flu vaccine reduced the risk of cardiovascular death by 66% in patients with acute coronary syndromes six months after receiving the vaccine. "We now realize that the vaccine gives protection for at least one year," said Dr Gurfinkel in an interview with the National Review of Medicine.

The study enrolled 200 MI patients and 101 angioplasty and stent patients without unstable coronary artery disease, prior by-pass surgery, angioplasty or tissue necrosis. The patients all received standard medication and were randomly assigned to receive either a flu vaccine or remain unvaccinated.

The incidence of cardiovascular death was significantly lower after one year in patients who had received a flu shot (6%) compared to the control group (17%). Dr Gurfinkel noted that the greatest benefit was seen in the MI patient group, who had a 4% incidence of cardiovascular death, versus a 21% incidence in the control group.

The results of the study appear to confirm findings of previous studies, indicating that the flu vaccine may protect against cardiovascular disease. A large observational study published in the New England Journal of Medicine last year suggested that the flu vaccine may reduce hospitalizations for cardiac disease and stroke as well as reduce all-cause mortality.

The flu or the vaccine?
The mechanism by which theflu vaccine protects against cardiovascular disease is still unknown. According to Dr Gurfinkel, some researchers suggested that getting the flu increases the risk of cardiovascular disease and that the flu vaccine reduces the risk by reducing the risk of the flu. "We are not totally convinced," he told the NRM. "One of the hypotheses we have is that the vaccination may interfere in the immune system. Vaccinations, particularly flu vaccinations, are a tremendous stimulus to the immune system." To test their hypothesis, Dr Gurfinkel and his colleagues are planning to study the effects of administering the vaccination in the summer time.