Influenza experts predict a high uptake of state-funded flu vaccination this year, following a big increase in demand for the vaccine.

More than 500,000 doses have been distributed to clinics this free-flu-vaccination season, which runs from mid-March to the end of July - 160,000 more doses than at the same time last year. It is uncertain whether the Kate Winslet flu film Contagion, released last year, has fuelled demand.

The uptake of the free vaccination reached nearly one million doses last year.

It is free for the elderly, pregnant women and anyone else over 6 months who has any of a range of specified disorders, including asthma, heart disease and diabetes.

Others pay around $20 to $30 for the vaccine, although many businesses pay for their employees to be vaccinated.

Influenza is a mild to moderate illness for most, with symptoms, which come on suddenly, including a high temperature, a cough, aches and shivering. But it can cause severe complications and even death.

National Influenza Specialist Group spokesman Dr Lance Jennings, a virologist, indicated yesterday that New Zealand could probably expect to get off fairly lightly in the coming winter and spring influenza season, judging from countries now coming to the end of their flu season, although Japan and China were experiencing a late-season upsurge.

"Based on what has happened in the Northern Hemisphere during their past winter there has been relatively low activity.

"Some countries have been affected by H3N2 [an A strain influenza virus] and some by influenza B and, particularly in China and Southeast Asia, B has been predominant, with relatively little activity of pandemic H1N1 virus."

This year's Southern Hemisphere influenza vaccine contains antigens - virus fragments - that induce immunity against A-H3N2, A-H1N1 2009 swine flu and a B strain.

"H3N2 viruses are often associated with more severe outbreaks amongst older age groups, old people's homes for example," Dr Jennings said.

Generally around 300 people a year are hospitalised with flu.

Dr Jennings said doctors were seeing only sporadic, occasional cases of influenza, probably mainly among returning travellers infected overseas.

By Martin Johnston Email Martin