Oral Sex Is Not Considered Safe Sex
A number of studies have demonstrated that oral sex can result in the transmission of HIV and other sexually transmitted diseases (STDs).

Oral Sex is a Common Practice
Oral sex involves giving or receiving oral stimulation (i.e. sucking or licking) to the penis, the vagina, and/or the anus. Fellatio is the technical term used to describe oral contact with the penis. Cunnilingus is the technical term which describes oral-vaginal sex. Anilingus (sometimes called "rimming") refers to oral-anal contact.

Studies indicate that oral sex is commonly practiced by sexually active male-female and same-gender couples of various ages, including adolescents. Although there are only limited data about how often adolescents engage in oral sex, some data suggest that many adolescents who engage in oral sex do not consider it to be sex; therefore they may use oral sex as an option to experience sex while still, in their minds, remaining abstinent. Moreover, many consider oral sex to be a safe or no risk sexual practice.

In one national survey of teens conducted in the USA, 26% of sexually active 15 to 17 year olds surveyed responded that one "cannot become infected with HIV by having unprotected oral sex", and an additional 15% didn't know whether or not one could become infected in that manner.

Oral Sex and the Risk of HIV Transmission
The risk of HIV transmission from an infected partner through oral sex is much smaller than the risk of HIV transmission from anal or vaginal sex. Because of this, measuring the exact risk of HIV transmission as a result of oral sex is very difficult. In addition, since most sexually active individuals practice oral sex in addition to other forms of sex, such as vaginal and/or anal sex, when transmission occurs, it is difficult to determine whether or not it occurred as a result of oral sex or other more risky sexual activities.

Finally, several co-factors can increase the risk of HIV transmission through oral sex, including: oral ulcers, bleeding gums, genital sores, and the presence of other STDs.

When scientists describe the risk of transmitting an infectious disease, like HIV, the term "theoretical risk" is often used. Very simply, "theoretical risk" means that passing an infection from one person to another is possible, even though there may not yet be any actual documented cases. "Theoretical risk" is not the same as likelihood. In other words, stating that HIV infection is "theoretically possible" does not necessarily mean it is likely to happen-only that it might. Documented risk, on the other hand, is used to describe transmission that has actually occurred, been investigated, and documented in the scientific literature.

Various scientific studies have been performed around the world to try and document and study instances of HIV transmission through oral sex. A programme in San Francisco studied 198 people, nearly all gay or bisexual men. The subjects stated that they had only had oral sex for a year, from six months preceding the six-month study to its end. 20 per cent of the study participants, 39 people, reported performing oral sex on partners they knew to be HIV positive. 35 of those did not use a condom and 16 reported swallowing cum. No-one became HIV positive during the study. Due to the low number of people in the study, all that can be said is that there was a less than 2.8 per cent chance of infection through oral sex over a year.

In June 2002, a study conducted amongst 135 HIV-negative Spanish heterosexuals, who were in a sexual relationship with a person who was HIV-positive, reported that over 19,000 instances of unprotected oral sex had not lead to any cases of HIV transmission. The study also looked at contributing factors that could effect the potential transmission of HIV through oral sex. They monitored viral load and asked questions such as whether ejaculation in the mouth occurred and how good oral health was. Amongst HIV-positive men, 34 per cent had ejaculated into the mouths of their partners. Viral load levels were available for 60 people in the study, 10 per cent of whom had levels over 10,000 copies. Nearly 16 per cent of the HIV-positive people had CD4 counts below 200. The study, conducted over a ten year period between 1990 and 2000, adds to the growing number of studies which suggest varying levels of risk of HIV transmission from oral sex when compared to anal or vaginal intercourse.

At the 4th International Oral AIDS Conference held in South Africa, the risk of transmission through oral sex was estimated to be approximately 0.04 per cent per contact. This percentage figure is a lot lower than the American figures, because this figure is a risk per contact percentage, whereas the other figures are percentage risks over much longer time periods. Oral sex is still regarded as a low-risk sexual activity in terms of HIV transmission, but only when more work is done will we be clearer as to the risks of oral sex.

Theoretical and Documented Risk of HIV Transmission During Oral-Penile Contact

Theoretical:
In fellatio, there is a theoretical risk of transmission for the receptive partner (the person who is sucking) because infected pre-ejaculate "pre-cum" fluid or semen can get into the mouth. For the insertive partner (the person who is being sucked), there is a theoretical risk of infection because infected blood from a partner's bleeding gums or an open sore could come in contact with a scratch, cut, or sore on the penis.

Documented:
Although the risk is many times smaller than anal or vaginal sex, HIV has been transmitted to receptive partners through fellatio, even in cases when insertive partners didn't ejaculate or “cum”.

Theoretical and Documented Risk of HIV Transmission During Oral-Vaginal Contact

Theoretical:
Cunnilingus carries a theoretical risk of HIV transmission for the insertive partner (the person who is licking or sucking the vaginal area) 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 (the person who is having her vagina licked or sucked) if infected blood from oral sores or bleeding gums comes into contact with vulva or vaginal cuts or sores.

Documented:
The risk of HIV transmission during cunnilingus is extremely low compared to vaginal and anal sex. However, there have been a few cases of HIV transmission most likely resulting from oral-vaginal sex.

Theoretical and Documented Risk of HIV Transmission During Oral-Anal Contact

Theoretical:
Anilingus carries a theoretical risk of transmission for the insertive partner (the person who is licking or sucking the anus) if there is exposure to infected blood, either through bloody fecal matter (bodily waste) or cuts/sores in the anal area. Anilingus carries a theoretical risk to the receptive partner (the person who is being licked/sucked) if infected blood in saliva comes in contact with anal/rectal lining.

Documented:
There has been one published case of HIV transmission associated with oral-anal sexual contact.

Other STDs Can Also Be Transmitted Through Oral Sex

Scientists have documented a number of other sexually transmitted diseases that have also been transmitted through oral sex. Herpes, syphilis, gonorrhea, genital warts (HPV), intestinal parasites (amoebiasis), and hepatitis A are examples of STDs which can be transmitted during oral sex with an infected partner.

Reducing the Risk of HIV Transmission Through Oral Sex

The already low risk of becoming infected with HIV from oral sex can be reduced still further by using latex condoms. For cunnilingus or anilingus, plastic food wrap, a condom cut open, or a dental dam can serve as a physical barrier to prevent transmission of HIV and many other STDs.

Source:
This page is based on the Centers For Disease Control Factsheet, "Preventing the Sexual Transmission of HIV, the Virus that Causes AIDS: What You Should Know about Oral Sex" (December 2000).