Hospitals across Ireland can expect to see between 600 to 900 new cases of flu every week due to a surge in the virus.

With cases expected to peak at the end of December, the HSE's clinical officer Dr Colm Henry said it is not too late to get the flu vaccine.

On The Pat Kenny Show, Dr Henry said a number of groups, including people over 60 and those with a chronic illness, can get the vaccine for free.

"It doesn’t become effective until two weeks after you take the vaccine so we’re urging people to get it as soon as possible," he said.

"Even if the cases peak at the end of December, we’ll see ongoing high numbers of influenza right through to January which will obviously cause illness if it gets through to people with serious underlying conditions."

A patient sits on a hospital bed, Alamy

Cases of flu may also spike when children return to school and adults return to work in January.

Dr Henry said a surge in the flu will put hospitals and healthcare providers "under ongoing pressure".

In addition to vaccination, Dr Henry urged the public to "be mindful" of who they come into contact with if they develop flu symptoms.

"An older person or a very young baby may be particularly vulnerable," Dr Henry said.

"[If you're sick] avoid contact with them and avoid visiting hospitals and nursing homes.

"Ideally, people should stay away from work until they're symptom-free for 48 hours."

Serious symptoms

Dr Henry said patients should go to the emergency department if they develop very serious symptoms such as shortness of breath, chest pain, a very high fever or confusion.

The HSE will be expanding GP services over the next few weeks.

Information on the flu vaccine from the HSE can be found here.

Feature image shows a hospital department, Alamy.