The probability of HIV transmission depends on the specific circumstances of the transmission. If a person with HIV has sex with another person without safety precautions, the probability of HIV transmission from one such act is estimated to be 0.1%, which is not the actual statistical probability, but only for reference. The probability of transmission is higher if there is a break in the skin or mucous membrane during sex, or if there is same-sex transrectal sex. It is also possible for a person with HIV to be infected through contact with other people’s broken wounds through their own blood or body fluids containing HIV, which corresponds to some cases of occupational exposure, with a probability of 0.3%. If these bodily fluids only come into contact with the mucous membranes of normal people, the probability can reach 0.09%, but of course, this is all for reference. Blood, semen, vaginal secretions, breast milk or thoracoabdominal fluid from an AIDS patient that comes in contact with the intact skin of another person will not cause transmission and the probability of transmission is 0%.