Researchers involved in a multimillion dollar New Zealand influenza study say children under four should be vaccinated.
Hospitalisation rates for influenza in the past year were the fourth highest in 12 years - much larger than anticipated - and children under four and the elderly were the hardest hit, data from Auckland and Counties Manukau district health boards shows.
The Southern Hemisphere Influenza Vaccine Effectiveness Research and Surveillance (SHIVERS) study aims to give a better picture of hospitalisation rates.
The study is an international effort to control global flu pandemics and may contribute to better understanding of flu throughout the world.
It is a collaboration between the Auckland and Counties Manukau health boards, Otago and Auckland universities, US Centers for Disease Control and Prevention (CDC) and the World Health Organisation Influenza Collaborating Centre at St Jude Children's Hospital in Memphis.
CDC contributed US $500,000 in additional funding for the project's second year, on top of $1 million in funding for this year.
A total 1370 cases of severe acute respiratory infection were recorded by Auckland and Counties Manukau health boards between April and September, including 38 intensive care unit admissions and seven deaths.
Flu contributed to five per cent of cases.
''This year hospitals were overloaded with respiratory illness,'' Auckland microbiologist Dr Sally Roberts said.
Middlemore Hospital paediatrician Dr Adrian Trenholme said: ''A significant part of the burden is potentially preventable.''
Immunisation rates for children under the age of four are just six per cent.
New Zealand does not yet have data on the effectiveness of flu vaccines, though overseas figures put it at 70 per cent.
The effectiveness of vaccines in children under four is being analysed as part of the project, the study's principal investigator, Dr Sue Huang said.
Internationally, vaccines have shown to be not as effective in the younger age group.
Next year the study will expand to include GP visits in Auckland to give a fuller picture of the disease.
- Auckland Now
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