Tongtong,
Just to share.............
Vaccine is usually made of either dead virus or some "man-made" structure that can trigger the immunity for that particular disease.
You said "The effect will only show later part of life, it wont happen immediately now" - I don't agree cos although it's true when they make the vaccine, they have to add in some chemical into it, but our body is smart enough to clear all those chemical in due time, in a matters of hours or days. Unless a person is so weak, then might take few months or years to clear. If a person can't clear the chemical away, his immune system must be faulty to a very severe extend. None of the vaccince will pass the FDA if the chemical added can't be cleared away by our body naturally.
You said "We can see childhood cancer/childhood disease which have apparently no reasons for it" - most of the childhood disease is inherited, including cancers, meaning they are born with a/some faulty genes. Or the child is born with weak immunity (again, also due to the genetics). It's not that no reason for it, but for some reasons we cannot see with our naked eyes.
Immunology is a very very very complex process. For those we can control - diet, environment, we do our best to control it. For the genetic makeup, nothing we can do.
But I'm telling the wrong person lar, think Wendy will be more sympathetic. 
