More children under five years are suffering from flu while there has been a decrease in all other age groups.
The number of people who have died from the flu since October last year has risen to 21 according to the HSE's Health Protection Surveillance Centre.
There were an additional 12 deaths reported to the HPSC last week.
The number of people hospitalised with the flu has fallen from 254 to 215 over the last two weeks.
There were 767 confirmed flu hospitalised cases during the current flu season and 55 admissions to critical care.
HSE director of public health, Dr John Cuddihy, said those hospitalised with flu were mainly children under five years and those aged over 65.
“The highest rate of hospital admission is in the one to four-year-olds and the next highest, under one. Children still have relatively high admission rates, compared to other age groups,” he said.
Of those admitted to critical care, the highest rates are in those aged 45 years and older.
There have been 35 respiratory disease outbreaks in healthcare settings, and 13 were due to flu.
Dr Cuddihy said most of the hospitalised cases were due to influenza A (H1N1).
All indicators suggest that the flu peaked during the second week of January this year.
If there was a continued decrease in these indicators in next week's data that would confirm that in week two influenza had peaked, he said.
Dr Cuddihy warned that flu will continue to circulate in the community for another four to five weeks, albeit at a decreased rate.
HSE national director of services, Joe Ryan, said there has been an 8.8% increase in the number of people attending hospital emergency departments so far this month, compared to the same time last year.
Admissions from EDs are almost 11% higher than the same period last year, with many suffering from respiratory conditions as well as flu.
The number of 75-year-olds being admitted is just 3.5% higher than last year.
Despite a higher level of activity in EDs, the total number of people on trolleys this month to date is 14.1% lower than last year.