[ private ]
[ she has to think about it for a bit. although there was no cure... ] There was a... something in a needle. You jabbed it into your stomach and it would fight off the symptoms. I think it was made from the blood of a friend of mine...
Uh, the reason the disease only shows when you leave Hinimizawa is because that's where the Queen Carrier of the vaccine is; her name is Rika. She's the reincarnation of a god, and she was the only one immune to the disease and the only one who could stop it spreading.