I nursed dd until she was 25 months. She is completely non-vaxed, and will remain that way. While continued bfing would have offered her continued benefits, weaning did not undo the 25 years of bm that she had. It built her an amazingly strong immune system that she will have for life.
Dd is around all sorts of other kids all the time. She goes to pre-school 3 times a week, she plays at the park, the mall, playdates, etc. She eats a healthy diet, gets a good night of sleep, laughs a lot, and lives a lot. If she gets exposed to some germs, that's ok! That's what helps to build her immune system. She will get sick, but she will get better. It's all a part of life.