I don't tell them anything. I don't talk about it to people who might have an issue with my decisions.

Having said that, that argument does have merit. No vaccine is 100% effective. It just reduces the risk of getting something and perhaps the severity. So i think people are within their rights to be concerned about being around my child who might not be vaccinated. I am an increased risk to them if my child is unvaccinated as i am more likely to get that particular illness. My MG was half and half though, half vacc and half didn't. We all knew and nothing much more was said, but if anyone had a slight illness they didn't come to mg.