Professor Philip Nolan:

The test we have is an excellent diagnostic test when used under clinical supervision where one has a high suspicion that a person has the disease, with a one in 100 chance or a one in 500 chance of having the disease. When one gets down to screening, however, it is a very poor test. It will miss a lot of cases and will come up with a lot of false positives if there is only a one in 20,000 chance or one in 10,000 chance that the person has the disease. This shows the limitations of testing. A negative test does not necessarily prove the person does not have the disease. If the risk is low, sometimes a positive test can be false. We need better testing technologies and better testing regimes. Certainly, from the research and literature on what we know, strict self-isolation or restricted movements will always be part of a travel regimen. This is what protects from the spread of the disease. We may be able to improve testing regimens that can shorten the time or change the nature of the time but realistically, in the long term, we are going to be living with restrictions on movement, perhaps alleviated somewhat by a better testing regimen. Right now we are not in that place.