Flu cases almost tripled across Ireland last year, infecting close to 12,000 people, the latest figures show.
The HSE has appealed to people to get their vaccines on time, as it released the last full weekly disease report of 2018.
A late arrival of the flu season has led to warnings that cases will rise in the coming weeks, heaping pressure on hospitals across the country.
The report documents the number of recorded diseases nationwide by the week ending December 29 - and states there had been a recent rise.
Two deaths have been reported over the flu season to date, while 10 people were admitted to intensive care due to the severity of their illness.
Some 62 people in total were in hospital with flu over the last two weeks of December.
This brought a total of 131 people hospitalised with a strain of the flu.
Some 47 of these were children aged between one and 14, with one taken into intensive care, while 21 were over the age of 65.
Overall, the figures show there were 11,708 cases of influenza in 2018, compared to 3,369 in 2017 - an increase of 247pc.
Mumps cases almost doubled, from 291 cases in 2017 to 577 in 2018, while measles more than tripled - from 25 cases in 2017 to 82 last year.
Meanwhile, there were five cases of rubella recorded last year, compared to none in 2017.
On a positive note, there was a notable decrease in the rotavirus infection, a serious stomach bug. In 2017, 2,305 cases were recorded. However, last year there were just 636 cases of the virus.
There was also a notable decrease in whooping cough cases, with 117 recorded in 2018 compared to 263 the year before.
Sharing the information, the HSE National Immunisation Centre added that "the best way to prevent outbreaks of disease is by getting your vaccines on time".
Earlier this week, the HSE warned that rising flu levels will affect the number of emergency department attendances and admissions over the coming weeks.
It said that while flu-like illness has not had a significant impact on numbers attending emergency departments to date, there are now signs that flu levels are rising.
It is expected this will affect the number of attendances and admissions in the coming weeks.
The HSE said the number of patients attending emergency departments continues to increase year on year, with 1.2 million attendances - an increase of 42,000 on the same time last year.
Between 25pc and 30pc of patients attending emergency departments require further treatment.
Yesterday morning, some 364 people were on trolleys or wards for admission to hospitals across the country, according to the Irish Nurses and Midwives Organisation's Trolley Watch.
The worst affected was University Hospital Limerick with 41 and Letterkenny University Hospital with 33.
In total for December, just over 7,000 patients were on trolleys or in overcrowded wards nationwide.