Anti vaxxers and being around my newborn

My sister in law and her kids are coming in from Hawaii to visit our family and the newest addition. She doesn't believe in vaccinating her children, her oldest is up to date but her youngest has not had any shots and she's 4. I don't have any ill feeling towards her decision, but I don't want her kids near my baby. I politely (and as sweetly as I could say it it) told her she's not allowed near my baby, and neither are her children. I feel so heart broken about it, because I love her to pieces, especially the kids, but my baby's safety and health comes first. Is this wrong? Do most mothers who don't vaccinate their children get told this often? 😞 I feel for her, and I miss her so much... I just can't risk it.