So far, fewer than 10 people have died as a result of the flu, which officially started in Ireland on December 11.

The latest data shows that between seven and 14 people every day are presenting at hospitals with the flu.

The HSE confirmed this figure yesterday, while 592 people remained on trolleys around the country.

However, there is still a low level of take-up for the flu vaccine among hospital staff, as it is not mandatory.

“What’s very interesting is, with nursing two to three years ago, [the vaccine uptake] was down in the low teens, now it’s over 30%. We’ve seen a big change,” said the HSE’s assistant national director for public health, Dr Kevin Kelleher.

“The evidence from the UK is that if we carry on like the UK, in three or four years’ time, we should be well up into the 50s.”

Asked if hospital staff could be forced to take the vaccine, he said the HSE uses an incentive approach.

“It’s a big debate about mandatory vaccination, which is split around the world, with North America that has gone hard down the mandatory line. Whereas Europe hasn’t. A lot of the belief in Europe is if you do things like we’re doing (incentivising people to get the vaccine as opposed to it being mandatory) you start to see change — and we have started to see change.”

Pressed for figures on the exact number of flu notifications the HSE has received, he was unable to give a definite answer for this week. He said the HSE will have better results next week.

A spokesman for the HSE said yesterday up to 14 people a day are presenting at hospitals with the flu.

Flu is a serious illness which can be life threatening - especially for people aged 65 and over or anyone a long term medical condition. Get the vaccine. https://t.co/iFKKZXagre #YourBestShot pic.twitter.com/mNgVKmdShE — HSE Ireland (@HSELive) January 2, 2018

“In our daily dialogues with hospitals and hospital groups, we are seeing that hospitals are saying, when they test at the point of admission, that there are between seven and 14 patients a day in larger hospitals coming in who test positive for flu.”

Dr Kelleher stated that in one part of the country, there had been a reported trebling of flu notifications.

“For one part of the country, they have seen a trebling of the number of notifications of the flu this week up to today (Thursday) and the week doesn’t finish until tomorrow.”

There are currently two main strains of the flu in Ireland, the A and B virus, with the former affecting the elderly and the latter affecting people under the age of 20. Dr Kelleher said more children are contracting it than older people.

The average flu season lasts between eight and 12 weeks, peaking in and around the fourth to sixth week, which Ireland is now approaching.

People who fall sick should look after themselves at home rather than going to already overwhelmed hospitals, Health Minister Simon Harris has said.

The intervention came as health chiefs urged workers to take sick days if they have flu symptoms and for children to be kept at home if it is suspected they have flu as hospitals were hit by the worst overcrowding crisis on record.

“I would appeal to everyone to listen to the public health messages of the HSE in the coming days and help our frontline staff by staying home if you’re ill,” he said.

Mr Harris apologised again for the unprecedented overcrowding crisis. “I am committed to breaking the cycle of overcrowding in the health service.”