Anal and oral sex: the facts, stated plainly

What the evidence says

Two pieces of sexual-health folklore are wrong in dangerous directions. Anal sex is not lower-risk for infections: the lining of the anus is thin and easily damaged, so the risk is higher, not lower, and for HIV the receiving partner's risk is far higher. Oral sex is lower-risk than intercourse but not zero: chlamydia, gonorrhoea, herpes, syphilis and HPV all spread through oral sex.

Public-health guidance states it plainly: the lining of the anus is thin and easily damaged, and anal sex has a higher risk of spreading infections than many other kinds of sex. For HIV, when a partner has HIV, the CDC estimates about 138 transmissions per 10,000 exposures for the receiving partner, against 11 for the insertive partner, before counting condoms, PrEP or treatment. Anything that has touched the anus should not then go into the vagina without a fresh condom or washing, because it can carry bacteria that cause infection. Pregnancy is still possible, though unlikely, if semen gets on or near the vaginal opening, even without vaginal sex. Through oral sex, chlamydia, gonorrhoea, herpes, syphilis and HPV all spread, HIV rarely can, and throat infections usually have no symptoms, which is why they are often only found when a test includes a throat swab. One caution in pregnancy: air must not be blown into the vagina, because of the rare but real risk of air embolism. Condoms and dental dams reduce these risks.

What this does not show

You can ask these things here plainly. The facts are stated without judgement, and they assume nothing about you, your partners or what you do. This is general sexual-health guidance, not specific to the condition, and none of it is a statement about your own risk, which depends on partners, testing and protection. It is not a complete STI or contraception consult: testing intervals, vaccination and emergency contraception are conversations for a clinician or sexual-health service.

Sources, as Neta holds them

1. Workowski KA, Bachmann LH, Chan PA, et al. Sexually transmitted infections treatment guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1-187. doi:10.15585/mmwr.rr7004a1

   Guideline synthesis

2. Centers for Disease Control and Prevention. About STI risk and oral sex [Internet]. Atlanta: CDC; updated 2024 Feb 6 [cited 2026 Oct 14]. Available from: https://www.cdc.gov/sti/about/about-sti-risk-and-oral-sex.html

   Guideline synthesis

3. Centers for Disease Control and Prevention. HIV risk and prevention estimates [Internet]. Atlanta: CDC; updated 2024 Nov 5 [cited 2026 Oct 14]. Available from: https://www.cdc.gov/hiv/risk/estimates/riskbehaviors.html

   Guideline synthesis

4. NHS. Sex activities and risk [Internet]. Page last reviewed 2022 Aug 15 [cited 2026 Oct 14]. Available from: https://www.nhs.uk/live-well/sexual-health/sex-activities-and-risk/

   Guideline synthesis

5. World Health Organization Department of Sexual and Reproductive Health and Research, Johns Hopkins Bloomberg School of Public Health/Center for Communication Programs. Family planning: a global handbook for providers. 2022 ed. Chapter 14, Male condoms [Internet] [cited 2026 Oct 14]. Available from: https://fphandbook.org/node/2682

   Guideline synthesis

6. NHS. Can I get pregnant if…: What if I did not have penetrative sex? [Internet]. Page last reviewed 2021 Apr 23 [cited 2026 Oct 14]. Available from: https://www.nhs.uk/CHQ/Pages/975.aspx

   Guideline synthesis

7. Jones C, Chan C, Farine D. Sex in pregnancy. CMAJ. 2011;183(7):815-8. doi:10.1503/cmaj.091580

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