Louise went on to discuss exposure . The first issue is type. Exposure can be insertive or receptive. It can be penile, vaginal rectal or oral. Comparing penile, vaginal and rectal exposure, the issue is the amount of time that part of the body is exposed.
Infected fluid can stay in the vagina for up to two days.
The second issue is number of exposures. A higher number of partners where no protection is used clearly increases the risk. The third issue is the chance of that partner's being infected. If someone is an injection drug user, for example, the risk is increased. Louise went on the discuss the body's resistance , a big part of the equation.