Not vaccinating question?

Anna
Going off another post I just replied to, how do children who are not vaccinated go to school? At least in New York you need a full vaccination record and now you even need a dental record, so I'm just wondering how children who don't have any vaccines are able to attend school? 
I only have a 16 month old so I'm naïve on the topic so if I'm wrong about something let me know! 
Oh and I'm pro vaccinate so don't think I'm trying to understand for my child lol