HIV is transmitted indirectly through body fluids.
HIV is mainly found in the bodies of HIV-infected patients, such as vaginal secretions, semen, blood, pleural and abdominal fluid, cerebrospinal fluid, amniotic fluid, breast milk, joint fluids and other bodily fluids, all of which contain HIV. If these substances come into contact with a wound of a healthy person, or through high-risk sexual behavior, they can cause HIV infection.
HIV is less prevalent in urine, feces, saliva, sweat, tears, and other fluids of HIV-positive people, so HIV is generally not transmitted through hugging, eating together, or shaking hands.
Vaginal secretions and semen contain large amounts of HIV and can be transmitted through sexual contact. Breast milk, amniotic fluid, and other bodily fluids also contain large amounts of HIV, so HIV can be transmitted to newborns through breastfeeding, and also during labor and delivery. HIV can also be transmitted through the placenta if the fetus is in the womb.