If the character is active and outgoing, where's the link to HIV?
No sex and there isn't much about blood transfusions or sharing needles on the regular show.
If it was a religion, it could be illustrated with artifacts and ceremonies from that religion.
If it was a nationality, it could be illustrated with a language.
And so on.
Unless the character develops AIDS or has to stay on a drug routine, just saying "Hi! I'm HIV positive, let's play jump rope!" will NOT mean anything to the kids.
"Hi! I'm HIV positive and I might develop AIDS and die. Let's play jump rope!"
Meaningless tripe from people who are still too afraid of the stigmatism to do anything worthwhile.