British researchers report influenza is known to trigger heart attacks, and may account for a 35 to 50% rise in heart attack deaths during the flu season.

Even though, getting vaccinated could prevent these deaths, less than half of vulnerable heart patients in Britain actually go in for a flu vaccine each year. Writing in the journal Lancet Infectious Diseases, Charlotte Warren-Gash from University College, London and colleagues insist, influenza vaccination should be encouraged, especially for those with an existing cardiovascular disease.

A review of 39-studies conducted between 1932 and 2008 on the potential links between flu and heart deaths showed, during the flu season, there was a rise in deaths due to heart disease or heart attacks, with seasonal influenza killing about 250,000 to 500,000 people every year.

Four out of eight studies revealed those who have been vaccinated against seasonal influenza, seemed less likely to suffer a heart attack. However, in Britain only 47% of people with chronic heart disease, asthma, diabetes or other conditions got a flu shot last year.

Worldwide, countries are gearing up to vaccinate hundreds of millions of people against the pandemic H1N1 swine flu.

American Heart Association and American College of Cardiology guidelines strongly recommend all individuals with cardiovascular disease receive annual influenza vaccination.