I'm glad this issue has gotten easier to deal with over the last 20 years. Admittedly, my experiences are out of date. A religious exemption in Nevada back in the 80s required letters from clergy with longstanding relationship. You had to be able to prove I think 5 years continuous involvement with the religion, but I could be wrong on the figure. I'm probably ok for any vaccines now other than my aversion to them. The side effects seem to be more severe for kids, and I didn't have any serious issues with the last ones I had, including some I needed for a 3 month stay in Mexico City. I'm really not sure what I would do if I had kids. I think vaccines do a great deal of good, but they do scare me. The percentages though are on the side of getting them done, but that isn't much comfort if your kid is one of the tiny % who has one.