Bazinga
Posting Freak
You can actually get them more than once, it's just rare.You can only get Chicken Pox once, so you can skip out "it's my first time".
Also, the adult version of the Chicken Pox is the Shingles, not the Measles, which is a common mistake portrayed by many cartoons aswell. src; My own Advanced Higher Biology knowledge
I also think Danny is 16 ;P