What Is the Risk of HIV from Oral Sex?

Separating Facts from Common Misconceptions

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After more than 35 years of epidemiological and biomedical research, the question of whether you can get HIV from oral sex remains confusing. So let's start by separating hypotheticals from the hard facts and statistics.

If asking can a person get HIV from oral sex, the honest answer would have to be possible but unlikely. For the most part, oral sex—either in terms of fellatio (oral-penile), cunnilingus (oral-vaginal), or anilingus (oral-anal)—is not an efficient route of HIV transmission.

With that being said, the word "can" suggests a theoretic possibility that many find difficult to dismiss.

What to Know About Oral Sex and HIV Transmission

Verywell / Laura Porter

Theoretic vs. Documented Risk

Whenever discussing HIV risk, it is important to differentiate between a theoretic and documented risk. A documented risk is based on the actual number of cases to which HIV can be directly attributed to an act of oral sex. And, when looking through that lens, the risk of infection by oral sex is actually extremely low. Not zero, perhaps, but edging close to it.

In fact, according to a study from the University of California San Francisco's Centers for AIDS Prevention Studies, the probability of HIV infection through unprotected oral sex was statistically zero, although the researchers went so far as to add that "we can not rule out the possibility that the probability of infection is indeed greater than zero."

For an individual perspective, there are numerous factors and situations that can increase personal risk, sometimes considerably. By understanding and identifying these factors, you can make better, more informed choices about the sexual health of you and your partner.

Estimating Risk by Exposure Type

The likelihood of transmitting HIV through oral sex depends largely on the type of contact involved. Putting aside all other risk factors, the potential for infection can vary based on whether the non-infected person is either performing or receiving oral sex.

Broadly speaking, the risk of HIV from oral sex can run anywhere from 0% to 1%, according to research from the London School of Hygiene and Tropical Medicine.

However, numbers can change once you factor in specific sexual behaviors. Among them:

  • Receptive fellatio, meaning that the non-infected person is performing oral sex on a male partner with HIV, is considered exceptionally low risk. Among men who have sex with men (MSM), the per-act risk hovers at around 0.04 percent.
  • Insertive fellatio ("getting a blowjob") is even less likely given that the enzymes in saliva can neutralize the HIV viral particles.
  • Cunnilingus has also proven to be a highly unlikely route.
  • Anilingus ("rimming") is also regarded as being of negligible risk, particularly for the receptive partner.

While these figures suggest that the risk of HIV is low from a population perspective, that shouldn't imply that it is inherently low from an individual perspective. Clearly, the more risk factors you have, the greater the risk of transmission will be.

Additional Risk Factors

Perhaps the single, greatest factor in determining the likelihood of infection is the viral load of the infected partner. Simply put, the higher the HIV viral load, the greater the infectivity of the person. By contrast, an undetectable viral load corresponds to a near-negligible risk.

There are a number of other factors that can influence the potential risk:

  • Ejaculation during oral sex is perceived to be riskier than oral sex without ejaculation, although there is no evidence that ejaculation is the sole factor for infection.
  • Cuts, abrasions or sores in a person’s mouth can offer a potential route of transmission. To this end, good dental health should be observed to help minimize bleeding gum disease and other oral infections.
  • Certain sexually transmitted infections, like syphilis and gonorrhea, can be asymptomatic. Infections like these can often go unnoticed, particularly if they present in the throat, vagina or rectum.
  • Lesions or sores from HIV-related infections like candidiasis or herpes simplex can also compromise the mucosal integrity of the mouth and throat. By taking HIV therapy, the risk of these other and oral infections can be greatly reduced.
  • The concentration of HIV in vaginal fluids can also increase during menstruation as HIV-bearing cells are shed from the cervix. The same can happen if a man gets urethritis, the acute inflammation of which can increase viral shedding even in persons with an otherwise undetectable viral load.

How to Minimize Risk

Clearly, the best way to minimize the risk of infection is to practice safer sex. This is especially true if you have multiple sex partners or are unsure about the health of a sex partner. These include condoms and dental dams for those engaging in cunnilingus or anilingus.

There are additional strategies that can further reduce risk:

  • If you are HIV-positive, take your HIV medicine as prescribed. If your viral load remains undetectable, you have effectively no risk of sexually transmitting HIV to HIV-negative partners.
  • If you are HIV-negative, you can ask your healthcare provider to prescribe HIV pre-exposure prophylaxis (PrEP), a once-daily drug therapy that can reduce your risk of infection by more than 90%.
  • Regular HIV screening is recommended for persons at high risk of infection, including MSM, injecting drug users, and persons with multiple sex partners. Periodic STD screenings are also recommended.

Finally, communication is tantamount to the long-term avoidance of HIV. Whether you are HIV-positive or HIV-negative, the most harm comes from leaving things unspoken. Learn more about ways to negotiate safer sex or how to disclose your HIV status to someone you're dating.

Frequently Asked Questions

  • What is the risk of HIV from oral sex?

    The risk of HIV from oral sex (including oral-penile, oral-vaginal, or oral-anal sex) is generally regarded as low to negligible. This doesn't mean that there is no risk but rather that the risk of transmission is theoretical and there are no well-documented cases of transmission via oral sex alone.

  • Why is the risk of HIV from oral sex low?

    There are substances in saliva that block HIV's ability to cause infection. Not only does saliva kill HIV-infected CD4 T-cells (a type of white blood cell that HIV targets), but certain proteins like mucin 1 and salivary agglutinin can render the virus non-infectious.

  • What might increase the risk of HIV from oral sex?

    While the risk of HIV from oral sex may be low, certain factors can potentially increase the risk of transmission, including mouth ulcers, bleeding gums, genital sores, or the presence of another sexually transmitted disease.

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11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Becerra JC, Bildstein LS, Gach JS. Recent insights into the HIV/AIDS pandemic. Microb Cell. 2016;3(9):451-475. doi:10.15698/mic2016.09.529

  2. University of California, San Francisco. HIV infection from receptive oral sex is a rare event, UCSF study confirms. August 14, 2001.

  3. Baggaley RF, White RG, Boily MC. Systematic review of orogenital HIV-1 transmission probabilities. Int J Epidemiol. 2008;37(6):1255-65. doi:10.1093/ije/dyn151

  4. Patel P, Borkowf CB, Brooks JT, Lasry A, Lansky A, Mermin J. Estimating per-act HIV transmission risk: a systematic review. AIDS. 2014;28(10):1509-19. doi:10.1097/QAD.0000000000000298

  5. Malamud D, Wahl SM. The mouth: a gateway or a trap for HIV?. AIDS. 2010;24(1):5-16. doi:10.1097/QAD.0b013e328333525f

  6. Centers for Disease Control. HIV transmission. Does my HIV-positive partner’s viral load affect my risk of getting HIV? Reviewed August 6, 2019.

  7. Centers for Disease Control. Oral sex and HIV risk. Reviewed November 8, 2019.

  8. CDC. HIV Treatment as Prevention.

  9. Patel P, Borkowf CB, Brooks JT. Et al. Estimating per-act HIV transmission risk: a systematic review. AIDS. 2014 Jun 19;28(10):1509-19.  doi:10.1097/QAD.0000000000000298

  10. Wood LF, Chahroudi A, Chen HL, Jaspan HB, Sodora DL. The oral mucosa immune environment and oral transmission of HIV/SIV. Immunol Rev. 2013 Jul;254(1):10.1111/jmr.12078. doi:10.1111/imr.12078

  11. Centers for Disease Control and Prevention. Ways HIV can be transmitted. Updated April 21, 2021.