Everyone is quarantined.
Start by testing a bunch of people to be the census takers. Make sure they're all clean.
The census people go door to door and test everyone in the home. When the test comes back negative, everyone in that home is free to do go back to normal life. In homes that test positive, those folks remain in quarantine until they all test negative too.
See? Easy peasy!
Yeah - I'm being facetious, for sure.