Privacy experts are advising individuals looking for COVID-19 proof of vaccination applications to be wary, NPR reports. Without federal regulation on a COVID-19 vaccination registry or app, many third-party apps have cropped up for individual use, but experts warn some come at a privacy cost of personal data. In finding a secure app, chief digital health physician at MITRE and cofounder of the Vaccination Credential Initiative Brian Anderson advised users to ask themselves if they trust and recognize the maker of an app.