We already have the ability to measure COVID status because diagnostic labs are required to report the presence of certain things to CDC in real time upon posit

We already have the ability to measure COVID status because diagnostic labs are required to report the presence of certain things to CDC in real time upon positive test result. COVID-19 is almost certainly one. Further, countries like Britain tried what you are describing and the process was a total shit show ultimately leading to failure. What makes flawless real-time communication hard is that you're talking about integrating thousands and thousands of groups of various sizes, with various technical capabilities and budgets, with various requirements, and with various legacy systems in place. You have multiple stakeholders who all want something different out of the project. You have very real security, availability, privacy, and fraud concerns. Oh and did I mention the government would really rather not pay for it? Just creating a practical UUID for every citizen in the US is unprecedented, let alone associating all existing historical data for one person from all over the country / world with that handle, parsing that data into a standard format, and creating a system where that record could be updated in real time in a secure manner. Unsurprisingly, it's a monumental undertaking.