We homeschoolers have chickenpox parties to expose our kids. There is no mutation. Same pox as I had.
I know a young couple who homeschool their children and don’t vaccinate. The husband was just getting a fledgling business started when the kids got chicken pox, he got it from them and almost died. He was extremely sick for 6 weeks and lost his business and all the money he had invested.
There are often life-long problems with the chicken pox virus. I had them as a child and I did fine, 2 of my grandchildren had them and scarred terribly.
My mother had measles as a 40 year old, years after we had all had them and she cared for us, believe me, she was one sick puppy.