[Question #13579] HIV and oral sex

3 days ago

Dear doctors,

I understand you phrase the risk as "extremely low", "for all practical purposes as nearly zero" for HIV tranmission via receptive oral sex.

I've also read a lot online from CDC, Catie.ca, Deutsche AIDS-Hilfe, AIDS-Hilfe Schweiz(official German and Swiss agency respectively ). They all state things such "extremely low", "almost no chance if partner doesn't ejaculate" (links - https://www.catie.ca/hiv transmission, https://www.cdc.gov/hiv/causes/index.html, https://www.aidshilfe.de/en/safer-sex-oral-sex, https://aids.ch/en/knowledge/hiv/transmission/).

I want to ask two things:

- Do you agree with public health messaging that what you classify as "extremely low risk" could by many of them be classified as "practically no risk", "negligible risk".

- If Partner A is HIV positive, untreated, would the risk of HIV transmission to Partner B during a single episode of 10 seconds oral sex be easily less than 1 in 100 000? My reasoning is: Baseline risk is 1 in 10000, the brevity of such exposure and no ejaculation further decreases the risk. I understand no clinical trials have been done on this.

H. Hunter Handsfield, MD

2 days ago

Welcome back to the forum.

You correctly summarize the facts -- the very low risk of HIV from oral sex and the agreement of various expert agencies.

"- Do you agree with public health messaging that what you classify as "extremely low risk" could by many of them be classified as "practically no risk", "negligible risk". Yes -- and this is pretty much what most experts and agencies do routine. Do not assume or look for differences between such statements as "extremely low", practically no risk,", negligible risk", and so on. There are no differences between them.

As for your partner A and B scenario, there simply are no data to allow such precise estimates. The often quoted risks of one chance in 10,000 (for penile to oral transmission) and one in 20,000 (for oral to penis) are extremely rough. I'd be OK with something like one chance in 100,000 (i.e. tenfold lower risk) in absence of ejaculation in the mouth. No clinical trials have been done on ANY quantitative risks of HIV transmission. All esimtates are based on surveys of people about how they thought the likely became infected and are very rough estimates at best. W/hat's more certain is that the busiest HIV/AIDS clinics rarely if ever see patients whose only possible exposures to HIV were oral sex.

Perhaps the best way for you to look at all this is to not obsess about numbers and know that you could have the kinds of exposures you have described in your two questions every day for your entire life and expect to never get HIV.

I hope these comments help you move on without worry. Let me know if anything isn't clear.

HHH, MD

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2 days ago

Dear doctor Handsfield,

many thanks for your reply.

I understand your point regarding clinical trials. Professionally, I come from a pharmaceutical sponsor side so I can see why clinical trials cannot be carried out here the same way one could perform a clinical trial in other therapeutic areas(ethical considerations, patient recruitment etc..)

Your answers are very thorough and I wanted to use this opportunity to thank both you and Dr. Hook for your expertise and all the work you do.

H. Hunter Handsfield, MD

2 days ago

Thanks for the thanks. I'm glad to have helped.---