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Risk of HIV Transmission Through Oral Sex |
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Oral Sex and the Risk of HIV Transmission
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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 unprotected serodiscordant pairings, 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 2000, a different San Francisco study of gay men who had recently acquired HIV infection found that 7.8 per cent of these infections were attributed to oral sex. However, the results of the study have since been called into question due to the reliability of the participant's data.
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 two 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.
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