I think though that this is the case with many VPDs...they just do not get diagnosed or get mis-diagnosed as something else because doc figures "vaxed for that, couldn't possibly" and diagnoses as something else...and the vaccine has changed the actual symptoms of the virus/disease and so it no longer looks like the traditional symptoms.
I have been thinking about this in regards to polio.
Do doctors ever test for polio anymore, in the US? When nonparalytic polio presents as a flu-like illness, isn't it possible that polio is still around, and just not as damaging as it once was, for whatever reason (no more smallpox shots or OPV; nutrition; hygiene; virus mutation; etc.), or that it is still around at a subclinical level? I may be way off on this and maybe doctors do still test for it or perhaps there is some other way of knowing, but I do wonder if it is misdiagnosed as something else, as many cases that were diagnosed as polio in the 50s were actually another illness.