Professor Mark Ferguson:

Yes. What I have described would be a pretty good sign that such a person was relatively safe. What do I mean by that? The antigen test determines whether one is infectious and may pass on the virus. One is much less likely to pass on the virus if one is vaccinated. If one is in the category of those who may pass on the virus despite being vaccinated, which is rare, that should be picked up with an antigen test. When those two things are combined, it is fairly safe to say that most infectious people would be caught and that it would be a satisfactory regime. I emphasise that no regime is perfect. There will always be one or two things, even with PCR testing, that allow people to slip through. That is not the game we are in. We are in a numbers game. It is a matter of trying to prevent most people passing on the virus and trying to allow them to be safe. The combination of vaccination and rapid testing will allow that to be done. If this was to be combined with people wearing masks on aeroplanes, I would feel very confident.