A contact tracing system and a virus with n days of non-symptomatic incubation, and international borders. Let's think this through a bit. Of what benefit is to the traveler admitting/host country (H) to note on the "medical passport" issued by origin country (O)? Obviously, for this thing to even work on paper, countries need to exchange massive amount of information.
The fact stands [challenge it!] that the socio-political regime being rolled out in guise of defense against Covid-19 and future viral friends aligns perfectly with a specific ideological position. It really was 'Nature's gift'.
What used to be accomplished via violent revolution is being accomplished with 'scientific' efficiency and very little blood. Oh, that figurative blood in the streets of middle and lower classes? "The Virus does not discriminate!".