Parents have the right to decide what medical treatments their children receive because they are ultimately responsible for their well being, not the state. For children the risks of the vaccine outweigh the benefits since children usually have mild symptoms and do not necessarily infect others. Studies done in school settings show that transmission rate is very low.
Unelected state officials have no business telling families what they can do with their health decisions, especially when it is about an experimental vaccine. We are not your guinea pigs!