Professor Paddy Mallon:

I would estimate the quickest turnaround time would be three to four hours, with batch testing and PCR-based assays.

The other caveat is that, as previously mentioned, that will identify the day zero positivity rate, which at the minute for contacts is 10%, but it does not predict if that person is going to develop symptoms. Therefore, it is useful for that day to remove people who are infectious but it does not solve the problem of ensuring that we follow up those people who are coming from high-risk areas to ensure they do not subsequently develop infections over the coming days, because that will still transmit and cause infections in the country.