You will know when a patient visits a study site from the deidentified data. At minimum they will have two visits for shots and a follow-up for a blood draw.

You will know when a patient visits a study site from the deidentified data. At minimum they will have two visits for shots and a follow-up for a blood draw. You'll also know at least their approximate age and sex. Publicly available location trace databases and purchase histories are probably enough to match a lot of the trial participants.