The number of cases of flu in Northern Ireland has been higher than expected, a health official has said.
Deputy chief medical officer Dr Elizabeth Mitchell warned sufferers not to visit patients in hospital over the festive period.
She said: "Catching the winter flu is an unpleasant experience for most, but for more vulnerable groups, it can lead to complications that are more serious. This is certainly the case for patients who are already ill in hospital.
"Although I fully understand that relatives and friends want to visit their loved ones during the festive and New Year period, I would ask that if you are ill, please stay at home and only visit hospital once you have made a full recovery."
Flu is highly contagious. Most of those particularly vulnerable to the illness will have been inoculated already.
Dr Mitchell advised sufferers to stay at home and rest, drink plenty of fluids and take paracetamol.
She added: "This year's winter flu vaccine programme has had a good uptake but anyone eligible who has received an invitation from their GP but has not yet been immunised should still take up the opportunity."