Not according to US law.
So first it's not manslaughter (Even though I sufficiently proved it would be) and now it's not child endangerment? How about I sufficiently prove it again yes?
From legalmatch.com:

All of the diseases that are prevented by the MMR vaccines run the risk of seriously debilitating a child, and possibly killing them too. Not vaccinating your child is recklessness or indifference.
(From
http://www.shouselaw.com/domestic-violence273a.html )

These diseases can easily cause a child to have serious mental and physical pain, and if you're purposely not getting them vaccinated then you're willfully putting them in a situation where they could be injured or even killed.
So in other words, yes, it is child endangerment. Even legally.