We are saved, page-9

If there is never any vaccine I can see them incorporating some kind of bracelet system for travel. maybe on your wrist?

1 green light if you are negative
2 green lights if you are negative and results are within last few days
1 red light if you are positive
1 amber light if you haven't been tested in past few days
1 blue light if you have been in close radius to another bracelet that was red
3 white lights if the bracelet has been opened / removed / tampered with

You scan your bracelet as you board the plane and it has your passport / boarding pass details..

Honestly though I see a vaccine happening soon enough to not even bother with this path - however if no vaccine is ever found then there are certainly other options such as this to reduce risk and allow reopening of travel - maybe Olympic committee can do something like this (they can send donations may way for brain storming this haha)