Dr. Tony Holohan:

It is very important. It will be a very important function of an optimised and idealised public health system of the kind the WHO has been recommending, which consists of testing, referral, tracing, investigation and control measures, verification of those control measures and then surveillance around that. That is the package we must have in place to maximise our chance of keeping control. As Deputy Smith says, retrospective investigation of contacts is a very important part of all that.