KEY POINTS:
Influenza has been linked with an increased death rate from heart attacks, in a study highlighted by advocates of the flu vaccine.
The Russian-American study found the death rate from chronic heart disease in St Petersburg was on average 10 per cent higher during influenza epidemics than in the flu "off-season". The death rate from acute heart attacks was, on average, 30 per cent higher during the epidemics.
"Influenza vaccination should be advocated for patients at high risk of developing cardiovascular events," the researchers say in the European Heart Journal.
New Zealand's National Influenza Strategy Group, which promotes influenza vaccination, has picked up on the study.
Researchers believe the influenza virus causes an acute and severe inflammation, which can disturb the fatty deposits at the root of heart artery disease.
"This research reinforces what we have been saying for years," said Christchurch virologist Lance Jennings, the group spokesman. "Patients at high risk of developing complications of heart disease should be strongly encouraged to have the influenza vaccine."
The Institute of Environmental and Scientific Research estimates that of people eligible for state-funded vaccination, only about two-thirds of the elderly and one-third of younger people have it.
Those eligible are people 65 or older, and under 65 who have one or more chronic conditions including heart disease, respiratory disease and most cancers. The free jabs are available until June 30.
The group says uptake has been light this season, attributing this to the mild weather last month.
Dr Jennings said there were 652 hospital admissions for influenza in New Zealand last year, the highest for 17 years. The highest rate was among babies under a year.
Heart Foundation medical director Dr Norman Sharpe, commenting on the Russian statistics, said: "I'm a bit surprised that the association isn't stronger.
"We've known for a long time that heart patients, particularly older patients, are vulnerable to chest infections and influenza. We've recommended, perhaps not frequently or strongly enough, that they have the influenza vaccine for that reason."
An editorial in the European Heart Journal says the study is "a valuable addition to the evidence supporting a role for infections in cardiovascular disease".
But it notes: "Ambient cold temperatures are likely to have been closely associated with levels of influenza, and could well have contributed to the effect on coronary death observed, particularly given the setting of northern Russia."
