*** not trying to start a vax/antivax war here lol

My sister in law recently announced she is not vaccinating her son because she thinks vaccines cause autism, breathing problems, etc. I am due with my second baby in about a month. Obviously she won't be able to immediately get all the vaccines necessary to protect her. My husband and I are considering not allowing sis in law and her husband/kid around our daughter until she is better protected. What do you think? What would be your course of action if you were in my shoes? In hers? Opinions and comments welcome from both sides. ☺