With every mandate comes a bureaucracy to enforce that mandate. With every bureaucracy comes politics, and money, and lobbying, and rules, and compulsions, and eventually, fines, prison time, sanctions, and more. Some people apparently believe that this is preferable to simply letting parents decide on the matter. They assume that a politician-appointed bureaucrat will make better decisions than the doctors and parents who know each specific case. Having witnessed many government panels, boards, regulatory commissions, and similar bodies at work in my career, I must disagree.
-Ryan McMaken
http://www.lewrockwell.com/lrc-blog/who-will-decide-who-must-be-vaccinated/