Ok, going with that, and per your prior question as to how the SID would pertain to recording boosters.
Drivers licenses in some states are also Real ID compliant.
There is a file that is attached now to driver licenses.
If you've ever had to show ID to vote, or enter into a contract, you'll notice your DL will be scanned, or run through a machine much like a CC reader.
When Real ID is national by the deadline in May 2023, your "vaccination" record will be in that file. As will booster dstes, because you will have to show ID for those as well.
It'll all a matter of being uploaded to your RID file.
Be aware too that the RID has a RFID chip too. As does the Enhanced Driver's License.
You can be tracked by RFID.
What is “Real ID” and will it affect your travel plans? | Depart Smart