None of the data you'd need to have policies based on calculated immunity is going to come quickly, if at all.

I don't think it's reasonable to try to run an open economy for those who are likely immune and a parallel economy for those who are unknown. There's no way anyone can verify any of that in a day to day setting.

I would expect that some international borders might reduce quarantine requirements if you can show evidence of probable immunity, but not right away.