Unless I am mistaken, this is not a question of "not releasing any information" but of "no one really knows why". If scientists had clear indications of why vaccinations dont work for some people, they should be able to work around the problem, or at least know ahead of time who they would be. But it's just the way some people are. My daughter's mother-in-law was vaccinated for mumps when she was little, but still got it three times. Three times! For some reason, her body just doesn't produce lasting immunity the way most of us do.