when to take newborn out?

So I just read on the news that there's the first confirmed case of the measles in my county. Now I'm so nervous to go out with my son who's due next month. To make it worse my sister in law and her sister have never vaccinated their children, and they live here as well so I'm super nervous about my baby being exposed to those kids before he can have all of his vaccinations. How should I handle this situation? I want my brother and sister in law and nephews to be able to see my baby but I just don't know that's it's worth it while he has no immunity towards the illness. After he is fully vaccinated I'll feel better but am I being crazy for not wanting them to be around him?