I need help. My sister has a 4 year old, and I have a 3 year old. I just found out she is anti-vaxx. Am I wrong for wanting to keep her away from my son indefinitely?

I iust discovered she doesnt believe in vaccines. I'm floored. I told her I dont want my three year old playing with her 4 year old anymore. We are all really close: me, my sister and her husband + 4 kids, along with my parents. We spend all holidays together. We are tight-knit. Finding this out was heartbreaking. I want my son to stay away from them now, and I feel like this is going to crush/ruin the family. I won't be able to spend the holidays with them anymore, or have them come to his birthday parties. I can already see my family hating me for this decision. Can you guys give me some encouragement/ advice? via /r/Parenting https://ift.tt/2VeYDPC