It's still the case in most (all?) of the US. However, it's generally pretty well accepted that the documentation requirements are lax and that parents can opt

It's still the case in most (all?) of the US. However, it's generally pretty well accepted that the documentation requirements are lax and that parents can opt out for a variety of reasons. When I was in school (both K-12 and college), my schools just accepted a paper document (trivially forgeable) that stated what vaccines I had received and when.