Why would this need to be on your phone? Many countries require proof of yellow fever vaccination before entry. https://en.m.wikipedia.org/wiki/International_C

Why would this need to be on your phone? Many countries require proof of yellow fever vaccination before entry. https://en.m.wikipedia.org/wiki/International_Certificate_of_Vaccination_or_Prophylaxis https://en.m.wikipedia.org/wiki/International_Certificate_of... I guess because, "on an iphone", is the thing now days. Having a digital version would be convenient but should never be a requirement. Oh wait, they have a digital version.