Is it possible to contract HIV from a positive person, within a few?
It is possible but highly unlikely. Estimates are that HIV is transmitted about one out of five hundred sexual encounters. So a short sexual encounter is even less likely to transmit it. When it does happen, heterosexual sex most commonly transmits HIV when one or both party have lesions. This could be an open wound, a part of the skin that is rubbed raw, or is in some way not perfectly healthy.