I feel like I encounter Dr. Oz wisdom more often than I do anti-vaccinators. As long as I don't start with "You are wrong because of X, Y, and Z," I feel that I'm normally able to find some sort of middle ground between where they started and reality. Creating the illusion of shared intellectual discussion often goes a long way. Example: "Oh yes I remember reading that article talking about the harmful effects of vaccination and I felt the exact same way as you do, but if I recall correctly they ended up rescinding those conclusions because of X, Y, and Z."