there are multiple hiv types and multiple subtypes, what there names are, and if it's possible to be infected by more than one type? thanks

I know there are many strains of HIV, and that's the main concern behind why Doctors cannot create a vaccine. I'm not aware of each and every type, and i'm not sure if you can be infected twice by 2 diff. strains. I remember there was an isolated case of what Doctors and the media referred to as "super AIDS" (went from HIV to AIDS in just months)in jan. from a man in NY, but I haven't heard of anyone being recently infected by it. Hope that helps