Babies and pre-schoolers were the age groups most likely to be seen by a doctor for a flu-like illness last year.
But their grandparents - the over 65s - made up the the biggest percentage admitted to hospital.
Environmental Science and Research's report on influenza for 2004 was released yesterday
and is based on figures supplied by 86 general practices around the country.
Dr Sue Huang, virology science leader at the crown research institute, said the high consultation rates for the under-5s were probably because parents acted quickly when their children became ill.
The lower GP consultation rates among people aged over 50 could be due to the higher vaccination rates among those groups - about 65 per cent of people over 65 were estimated to have been vaccinated.
But hospital admissions and deaths from flu were higher in the 65-plus group. Dr Huang said elderly patients possibly put off seeing their GP and ended up severely ill and in need of hospital care. People aged 65 and over made up 94.1 per cent of influenza deaths between 1990-98.
The report also shows:
* The 86 practices reported 3277 consultations for flu-like illnesses.
* Based on that, it was estimated that nationally 35,186 people went to their doctor with flu-like symptoms, compared with 46,116 in 2003.
* Influenza A dominated and about half of those cases were the Wellington strain - the one which the Sanofi Pasteur vaccine may not effectively protect against.
* Influenza A (H3N2) viruses had often been linked with more severe disease, pneumonia and death.
* A total of 430 people were admitted to hospital with the primary diagnosis of flu compared with 593 in 2003 and 490 in 2002.
