Rates of swine flu infection in the community have doubled in the past week, according to figures published this afternoon.
The numbers of patients hospitalised with flu has also increased three-fold in the past week. Some 114 patients so far this season had been hospitalised up to last night and 33 patients had been admitted to intensive care.
A week ago the numbers hospitalised since the beginning of the flu season in October stood at 36 and at that stage just five patients had been admitted to intensive care.
Most of those admitted to intensive care had not received the flu vaccine.
Meanwhile the latest figures from the national Health Protection Surveillance Centre show rates of influenza-like illness increased to 120.6 per 100,000 of the population in the week ending January 2nd compared to an infection rate of 59.5 per 100,000 the week before.
At a press briefing in Government Buildings, the State's chief medical officer Dr Tony Holohan said there have been no confirmed deaths from flu here to date this season. There have been 50 deaths from flu in the UK so far this season, including 45 from swine flu.
Dr Holohan said infection rates may continue to increase over the next two to four weeks before levelling off, but he stressed rates of infection are still not as high as they were during the swine flu pandemic.
Dr Kevin Kelleher, head of health protection with the HSE, urged those in at-risk groups including pregnant women and those with chronic health conditions to get the seasonal flu vaccine, which this year contains protection against swine flu and two other flu viruses which are in circulation.
He said schools will be issued with reminders when they reopen next week on the steps they should take to prevent the spread of flu.