One idea I read, which isn't practical logistically at all
is if someone could make a test that tells if you have ever had Covid-19 as well as if you still have it. If they could make enough of this test for the worldwide population (which isn't likely, though how they're going to make enough vaccines for the worldwide population, I don't know that either),
Then people could get tested and if they test that they've had Covid-19 and recovered and don't have it anymore, they get a mark on their SSN/identity card and some type of permanent identifying marker that lets them go back to regular day to day living.
But this would create a black market for those markers, cause non-immune people to mix in and spread the disease, cause people to purposefully try to get infected just to clear it and get back out, etc..etc... so wouldn't work.