Expecting a baby next month and step sister doesn't vaccinate. How to handle this particular situation?

I was discussing this topic with my brother and he told me to come here and ask. If this isn't the right place to post, I apologize. Point me in the correct direction if there is a more appropriate spot. I know this is a controversial topic and I would like for this to stay drama free.I live in the same town as my stepsister, my mom, and my stepdad. My mom and stepdad are about 10 minutes away and my stepsister is literally down the street from where I live. We all go to church together every Sunday and often get together to watch sporting events or have brunch. We all see each other at least once a week and often more than that.My husband and I are expecting our first baby in a month. The issue we have come across is that my stepsister doesn't vaccinate her kids. She has a 6 year old and a 3 year old. Neither of them have ever been vaccinated. She home schools and has mentioned that a number of the parents in her co-op don't vaccinate either.I'm just worried about my baby catching something serious. I don't consider myself to be overprotective, but I obviously want to protect my kid as I see fit. I know my niece (stepsister's daughter) had an awful case of chicken pox when she was a toddler. I don't want my son to experience anything like that. It was horrible.I am going to vaccinate my son, but there is a schedule we have to follow and it's not like I can vaccinate him as soon as he is born. Should I limit contact with my stepsister until he is older? What about if we have more kids? What is the best way to keep my kids safe in this situation?I would prefer not to end all contact. My siblings all live far away from me and I don't get to see them often. Although I disagree with my stepsister on a lot of issues, I do enjoy having someone I can talk to and cousins for my kids to grow up around. My siblings are all telling me to completely end contact with her but none of them like her, so I'm not sure how objective they are being in their assessment. Is that the only way to go? Ending contact forever? I'm not even sure how I am going to bring this up to her. There is absolutely no changing her mind on the topic of vaccinations and I would rather not preach information to her that she already knows. That's unfortunately not an option I have.Thanks for reading. via /r/Parenting http://ift.tt/2oAlSqA