Sandy B. Garfinkel and Emma M. Lombard of Eckert Seamans Cherin & Mellott, LLC write, in part:
If you are simply carrying a photographic image of your vaccine card in your phone, phones can be, and regularly are, hacked. Or, the owner of the phone may simply have inadequate protection from unauthorized access.
If you are using an app created explicitly for vaccine card authentication (commonly referred to as “vaccine passports”), you should still proceed with caution. Some “vaccine passport” programs connect to state-maintained databases for vaccine information. These apps have encountered security flaws.
Read more at Bloomberg Law.