Hello, Lily. I'm not a doctor, but I am a mom of 2 and it seems that more and more, children are coming down with chicken pox repeatedly. When I was 7 I caught them and never had them again. My mom said it was because I had quite a good case of them. If you caught them, but didn't break out very much, you could keep getting them until you broke out all over real good. Both of my children had them within 2 weeks of each other, and they were broken out all over. While shopping the other day, I was speaking with another mother who said her daughter kept "rebounding" with chicken pox and each time she only has 3 or 4 "pox". The mom, on the other hand, got her first case at age 31 and they turned into shingles. She said she was very ill for about a month. Hope this helps.