The flu vaccine is expected to be far more effective in the southern hemisphere than in the northern hemisphere, where, in England, it has achieved a success rate of just 3%.
Virologist Dr Lance Jennings, of the Canterbury District Health Board, said the southern hemisphere vaccine protected against the H3N2 altered strain missed by the northern hemisphere vaccine.
The southern hemisphere vaccine was formulated in October last year, to protect against three strains.
The present form of the H3N2 strain emerged in February last year, the month after the northern hemisphere vaccine was formulated, when it was too late to be updated.
The H3N2 strain became dominant in the later part of New Zealand's 2014 flu season, with H1N1 dominant initially. Unlike H1N1, the H3N2 strain affected more older people than younger people.
The effectiveness of the flu vaccine varied, and was usually about 60% to 70%, Dr Jennings said.
''We can't say how effective this current season's vaccine is going to be, but we can only go on ... previous years.
''The best protection against influenza is to receive the seasonal influenza vaccine,'' he said.
For more information, people should ask their GP about getting the vaccine.
It is funded for certain groups, including those aged over 65.
Dr Jennings is a spokesman for the Ministry of Health's National Influenza Strategy Group.
Last month, The Guardian newspaper reported that the vaccine was estimated to work in just 3% of cases in lab tests (conducted in England).
Its success rate could rise if other strains become more prevalent throughout the flu season, the paper reported.
The facts
• Flu vaccine to protect against H3N2, H1N1, influenza B.
• Effectiveness just 3% in England because vaccine missed variant of main strain.
• 1.2 million flu vaccines given in New Zealand in 2014.
