Why are vaccines for polio taken orally while vaccines for TB need to be injected?

Question

My thoughts are that maybe the TB antigens necessary to produce an immune response are proteins; therefore they can be digested in the stomach and small intestine. But I may be wrong though. I am confused why I can't say the same for polio vaccine.

Answer 1

When you swallow, the material goes down into your stomach. An area with a high acidity (aka Low-PH) and enzymes designed to tear proteins apart.

The effective parts of a vaccine are chunks of proteins and do not survive, so almost all of them must be injected.

Polio is a rare exception in that they can live live attenuated (made unable to cause the disease) vaccine. They get ripped up, but enough makes it into the bloodstream for it to be effective.