The Health protection Surveillance Centre (HPSC) is reminding people in high-risk categories to get vaccinated against the flu.

The HPSC says flu rates for the week ending the 16th December are higher than normal.

The increase occurred in all age groups except those aged over-65 and was most pronounced in school children aged 5 - 14.

One person was hospitalised this week and treated in the intensive care unit having been diagnosed with Influenza B.

Low flu activity in 2012

Doctors say symptoms of the flu usually develop over a few hours and include a high temperature, sore muscles, headache and sore throat.

Anyone with the flu should stay at home, rest drink plenty of fluids and use over the counter remedies like paracetemol.

The HPSC says influenza activity in Ireland was low during the 2011/2012-influenza season with GP consultation rates peaking at 41.3 per 100,000 population during week 8 of 2012:

Experts say you can tell the difference from a common cold because that comes on more gradually and includes a runny nose and a normal temperature.

Dr. Darina O'Flanagan is from the HPSC.

She lists the groups who need to get vaccinated.