There's been a rise in the number of HIV cases among the homeless so far this year.
According to the Irish Examiner there have been nine new incidents of the virus since the start of 2015 compared with none in the same period last year.
Now the HSE says they are investigating the scale of the increase and have set up a special intervention group to respond.
It's thought the number of new cases among the homeless could be linked to the injection of former head shop drug mephedrone and the abuse of tranquillizers called benzodiazepines.
Doctors and drug workers believe this may be contributing to a chaotic lifestyle resulting in the sharing of needles and unsafe sex.
