Here’s how to know who is vaxed:
Use secret NSA phone and text or emails, coordinated with FBI surveillance records and use the confidential medical data from doctors and hospitals for each person.
Example: “Mom’s going to the Covid vax place this afternoon.” then vehicle passes five intersection sensors and vehicle is sensed to be in the medical center parking lot. Space 124. Presented her Blue Cross card and computer scanner showed there is no charge for vax and this is recorded by FBI. Video of coming in and leaving center is also available. Text: “Got vax. That’s done.CU.”
Easy.
Actually it is a little bit easier. For example, California maintains a master list of people who have been vaccinated for anything, not just Covid. I’m sure many, if not all, other states maintain the same kind of database.