New figures show that the number of infections with the Respiratory Syncytial Virus (RSV), the winter vomiting bug (Norovirus), and influenza are all down compared with this time last year.
However, the Health Service Executive has said that a year-on-year comparison for RSV is not correct.
It said RSV is a seasonal virus and in January this year, there were low RSV cases due to high public health measures.
This compared, it said, with high numbers in January 2020.
The HSE said a similar situation applies to the winter vomiting bug and flu data when compared with last year.
The HSE said RSV has started earlier this year than in the past and that in the week of 6 November, there were 483 cases versus 43 for the equivalent week last year.
The RSV virus is one of the factors blamed for the current pressure on children's hospitals and general hospitals, along with the winter vomiting bug and influenza.
According to the Health Protection Surveillance Centre, 1,881 cases of RSV have been reported this year.
It compares with 1,947 cases up to the same period last year, representing a reduction of 66 cases.
For the winter vomiting bug, just 265 cases have been reported this year, compared with 534 for the same time last year.
That is a reduction of 269 cases.
In relation to influenza, the case numbers are significantly fewer - seven cases have been reported here compared with 7,777 for the same period last year.
The period covered is week 1-44 of 2021 compared with week 1-44 of last year.
