The benefits of vaccination to the individual are well established and should those benefits just sit with the individual, I suspect calls for compulsion would fall on deaf ears. The issue gets heated for four main reasons:
1. The benefit of immunisation is even greater for society than for the individual - herd immunity is a major goal of immunisation programmes.
2. Scare stories have abounded about side effects, most notably with MMR. While it is possible for most medical interventions to have side effects, vaccines are considered very safe and the autism and crohns links have been discredited.
3. Personal choice on how children are raised and treated. Nobody likes to be told what to do, and compulsion of this sort is felt to be an infringement of human rights.
4. Profit driving vaccination programmes, both profit for BigPharma and for GPs who get paid for high vaccination rates.
Personally I think that the human rights issue is the key. We must not make vaccination compulsory, but we must promote it as much as possible. Vaccination should, once again, become part of the routine of bringing up children - that is not to say that it should not be questioned. Parents should be able to make decisions on their child's health, but the information that they base their decisions on must be clear and unbiased. Promotion is the key to herd immunity.