December 20, 2013
Oral sex involves giving or receiving oral stimulation (i.e., sucking or licking) to the penis (fellatio), the vagina (cunnilingus), or the anus (anilingus). HIV can be transmitted during any of these activities, but the risk is much less than that from anal or vaginal sex. Receiving fellatio, giving or receiving cunnilingus, and giving or receiving anilingus carry little to no risk. The highest oral sex risk is to individuals performing fellatio on an HIV-infected man, with ejaculation.1,2
Even though oral sex carries a lower risk of HIV transmission than other sexual activities, the risk is not zero. It's hard to measure the exact risk because most people who practice oral sex also practice other forms of sex during the same encounter. When transmission occurs, it may be the result of oral sex or other, riskier sexual activities, such as anal or vaginal sex.
If the person receiving oral sex has HIV, their blood, semen, pre-seminal fluid, or vaginal fluid may contain the virus. If the person performing oral sex has HIV, blood from their mouth may enter the body of the person receiving oral sex through the lining of the urethra (the opening at the tip of the penis), vagina, cervix, or anus, or through cuts and sores.
Several factors may increase the risk of HIV transmission through oral sex, including oral ulcers, bleeding gums, genital sores, and the presence of other sexually transmitted infections (STIs).
In addition to HIV, other organisms can be transmitted through oral sex with an infected partner, leading to herpes, syphilis, gonorrhea, genital warts (human papillomavirus, or HPV), intestinal parasites (amebiasis), or hepatitis A or B infection.
Barrier methods can help lower the risk of getting HIV and other STIs from oral sex. A latex or plastic condom may be used on the penis, and a cut-open condom or a dental dam can be used between the mouth and the vagina or anus.
For information on reducing the risk of HIV infection from anal or vaginal sex, see "How Can I Prevent Getting HIV From Anal or Vaginal Sex?" and other Prevention Q&As.
Get answers to questions and locate HIV testing sites.
CDC HIV Website
National HIV and STD Testing Resources
CDC National Prevention Information Network (NPIN)
Technical assistance and resources.
Act Against AIDS
Treatment and clinical trials.
Comprehensive government HIV resources.