The HSE's Health Protection Surveillance Centre has urged people in high-risk categories to get vaccinated against influenza,

It says the number of reported cases of influenza-like illness (ILI) indicate that flu is now circulating.

The ILI rates for the week ending December 16 was 24.9 cases per 100,000 population which is above the threshold used to access influenza activity. The threshold for the 2012/2013 influenza season is 21 cases per 100,000 population, the HSE said.

"Influenza is now circulating in the community, it is important that people in high-risk categories get vaccinated against influenza," according to HPSC Director, Dr Darina O'Flanagan.

High-risk groups are:

* The over-65s.
* Pregnant women
* People, including children, with chronic illness requiring regular medical follow-up such as chronic lung disease,   chronic heart disease, and diabetes.
* Those with lower immunity due to disease or treatment, including those who have had their spleens removed
* Children or teenagers on long-term aspirin therapy.
* Residents of nursing homes, old people's homes and other long stay facilities.
* Health care workers and carers of those in risk groups.