Every normal person has been vaccinated. It is a requirement for getting into kindergarten, elementary, middle, and high schools. When I graduated from HS, they gave us empty leatherette cases, and told us to go to the commons to get our diplomas, and our immunization records.
Proof of immunization is also required to enter as an undergraduate. Ergo, an undergraduate diploma is proof of immunization. However, in my packet of 'little things to do in the two weeks before school starts,' immunization forms! No problem. However, they indicate that, rather than proving that I have had my shots, I need to prove that they did some good via blood titer.
Now, I'm not a doctor, yet, but something about this strikes me as odd. Under what conditions could someone be immunized, yet no longer be immune? I'd believe that the polio shot my mother got 40 years ago is starting to lose its impact, but my shots are much younger. The only way I wouldn't be immune would be if I had no immune system whatsoever. Anyway, I am, indeed immune to MMR, do not have tuberculosis, etc. thus I am here, and can get my hospital ID (see above).