Those who take these "vaccines" are the mice, rats, guinea pigs, ferrets, etc. in what is the largest Phase III clinical trial in medical history.

Phase III trials need to keep track of what animal received what version / lot of the "vaccine" was administered, hence the need to record the lot number.

A backup measure, a fail safe you might say, was put into place just in case someone lost their card or their record in the "database" could not be found. Videos have been posted that show cell phones with Bluetooth enabled that can read what might be a very small RFID chip that was inserted into body as part of the vaccine payload, something which @Nettie previously mentioned.