AIDS is transmitted through specific bodily fluids like blood, semen, vaginal fluids, and breast milk. A handshake involves no exchange of these fluids. In fanfiction, it's the same. It's just a physical contact that doesn't lead to the transfer of the virus. So, no matter what the context in fanfiction is, a handshake won't transmit AIDS.
AIDS is a serious disease with very specific ways of transmission. In fanfiction, which often borrows from real - life concepts. Handshakes are simple greetings. The virus that causes AIDS is not airborne or transferred through skin - to - skin contact like a handshake. It needs direct access to the bloodstream or certain mucosal membranes. So, whether in real life or in the world created by fanfiction, a handshake is not a means of getting AIDS.