SEXUAL ACTS

One of the most common ways HIV is transmitted is through sexual contact, primarily through unprotected vaginal or anal intercourse. In every act of sexual penetration, there is an inserter and a receiver. The receiver is generally at greater risk than the inserter is, although if the penis of the inserter has open cuts, sores, or ulcers, then the inserter’s risk will be increased.

With penile-vaginal sex, the female partner is generally at greater risk because of the greater exposed surface area in the female genital tract than in the male genital tract, the higher concentrations of HIV in seminal fluids than in vaginal fluids, and the larger amount of semen than vaginal fluids exchanged during intercourse.

Although HIV transmission through unprotected oral sex—cunnilingus (oral-vulva contact) or fellatio (oral-penile contact)—can occur, the risk is much lower than for unprotected vaginal or anal sex. However, this behavior is not free of risk. With oral sex, the person at greater risk is the one using his or her mouth to stimulate the other person’s genitals. The risk is increased when that person has open sores in the mouth or bleeding gums. The risk is also increased when that person receives semen in the mouth or swallows any secretions.

Unprotected anal sex (penetration of the anus by the penis) between two men or between a man and a woman is particularly risky because the chance of damage (small tears and lesions) to the thin lining of the rectum is high. This facilitates HIV transmission by enabling the virus in semen to quickly enter the bloodstream.

HIV transmission has also been reported through infected semen used for artificial insemination. Reputable sperm banks now test all samples before using the

Risk Associated with Specific Sexual Practices

Penile-Vaginal Sex
Male-to-female and female-to-male transmission provide strong epidemiologic evidence that heterosexual transmission of HIV does occur, presumably via penile-vaginal intercourse. Vaginal sex during menstruation may be a risk factor for transmission from an infected female to an uninfected male, but probably not for transmission from an infected male to an uninfected female

Oral-Genital Sex
Oral-genital contact is not completely risk free, in fellatio, there is a theoretical risk of transmission for the receptive partner because infected pre-ejaculate ("pre-cum") fluid or semen can get into the mouth. For the insertive partner, there is a theoretical risk of infection because infected blood from a partner's bleeding gums or an open sore could be exposed to a scratch, cut, or sore on the penis

Cunnilingus carries a theoretical risk of HIV transmission for the insertive partner because infected vaginal fluids and blood can get into the mouth. (This includes, but is not limited to, menstrual blood). Likewise, there is a theoretical risk of HIV transmission during cunnilingus for the receptive partner, if infected blood from oral sores or bleeding gums is exposed to vulvar or vaginal cuts or sores
Anilingus carries a theoretical risk of either transmission for the insertive partner, if there is exposure to infected blood, through bloody fecal matter (bodily waste) or cuts/sores in the anal area. Anilingus carries a theoretical risk to the receptive partner if infected blood in saliva is exposed to anal/rectal lining.

Anal-Genital Sex
Strong evidence exists that being the receptive partner in anal-genital intercourse is associated with a high risk of HIV infection. Transmission of HIV to the receptive partner probably occurs because of the deposition of HIV-infected semen on traumatized rectal mucosa. Receptive anal-genital sex has been consistently described as an independent risk factor for HIV infection among homosexual men. Results of several studies demonstrate that the greater the number of partners with whom receptive anal sex is practiced, the higher the risk of HIV transmission.