My source, who has investigated this for a Govt Agency (not the Min Health) says the Irish app is the only one known globally to work effectively. It is a Bluetooth proximity app utilising the Apple/Google API, no centralised database (i.e. all data is on the phone only) and is about 85% effective in tracking contacts. No user interaction to operate other than enabling Bluetooth.
I may have the 85% slightly wrong, I was slightly distracted when she mentioned the figure.