[Question #3157] 10-15 seconds of unprotected oral sex

37 months ago
Hello Dr(s),
My questions is in regards to risk assessment from an unprotected brief oral sex from a CSW (stripper) in Toronto, Canada.  This lasted for I would imagine 10-15 seconds before i stopped and asked her to put  the condom on.  I understand it is low risk for most and zero for some STD/I.  Additionally, 48 hours later I had unprotected vaginal sex with my wife.  My wife was prescribed cephalexin 500 MG (4 times a day for 7 days) for unrelated infection 3 days after our unprotected sex.  I do not have any discharge or pain during urination.  I do have some slight itching and feeling on fullness some times in my penis.  

This is the only risky episode (unprotected oral)  I have had in my entire life. 

My question(s) are as follows:

1.  Did I put myself or my wife at significant risk?
2.  Do I need to get tested for bacterial infections?  
37 months ago
I must add that this unprotected oral was 7 days ago. 
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
37 months ago
Welcome to the forum and thanks for your confidence in our services. Thanks as well for reviewing other questions similar to yours, as indicated byour your understanding that oral sex is low risk for all STDs and zero, for all practical purposes, for others.

In thinking about risks for exposures like yours, we can analyze several factors:  How likely your partner had an STD or HIV? If so, how likely was an oral infection? If orally infected, what is the transmission likelihood? And, if infected, what are the odds the infection is the cause of any symptoms that may have developed? Then a collective risk can be judged, from the basic mathematic principle that the individual risks have to multiplied; and that multiplying fractions results in smaller fractions at each step.  

We'll stick with the bacterial STDs, per your specific question, plus HIV. The first bottom line is that we can guess a roughly 10% chance a partner like yours has chlamydia or gonorrhea and under 1% chance for HIV and syphilis. Chlamydia is uncommon in the oral cavity and rarely transmitted when present; it can be dismissed. Gonorrhea is not rare in the throat, but still only ~5-10% of all persons with gonorrhea, which means no more than 1% chance she had it (10% overall x 5-10% oral  =  0.5-1% chance of oral infection. And when present, transmission probably occurs less than 10% of oral sex episodes, probably lower in your case given the brevity of exposure. So MAYBE as high as 1 chance in a thousand you would have caught gonorrhea from this event, probably more like 1 chance in 10,000 or even lower. Finally, 95% of gonorrhea causes obvious symptoms (pus dripping from the penis) within 2-5 days. So absence of symptoms at 7 days lowers the risk of gonorrhea to a still much lower figure. (The minor penile sympotms you describe are irrelevant, probably anxiety related.)

I won't go through a similar calculation for syphilis, except to say the chance you caught it surely is less than 1 in a million. And syphilis is not transmissible to partners before the initial sore (chancre) develops, typically 10-20 days later. HIV risk is even lower than for syphilis. (Both are rare in heterosexuals in eastern Canada, including sex workers.)

As for your wife, even in the slim chance you were infected, she would have been completely protected against gonorrhea by taking cephalexin within 3-4 days of exposure; and also against syphilis, but that's not an issue.

So finally to your specific questions. They're pretty well covered by all those comments. But to be explicit:

1) "Significant" can mean different things to different people, but I would say no significant risk -- virtually zero risk, in fact.

2) "Need" also is variable. If I were in your situation, for sure I would not be tested for anything. However, I'm not you -- and some anxious persons will be more reassured by negative test results than by even the most sophisticated or expert opinion. In other words, if my comments above -- any what I would do personally -- are sufficient for you, dont' do it. But if negative tests will help you move on, feel free. In that case, have a urine gonorrhea test (which automatically includes chlamydia), which is valid at this time; and, after 6 weeks, blood tests for syphlis and HIV. If you decide to test, you definitely can expect negative results.

I hope these comments are helpful, but let me know if anything isn't clear. Best wishes and happy new year!

HHH, MD

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37 months ago
You sir are an officer and a gentleman.  Thank you for your assistance.  I am going to ask a follow up which perhaps can be beneficial for other readers as well. 

1) HIV via oral transmission is termed as no risk by some Canadian health agencies.  You have also indicated, in other answers, that you have not seen any transmission through this route.  As a researcher, do you think there is need to have a controlled study on oral transmission or do you believe this subject is rather too expensive to tackle and presents too many variables?


H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
37 months ago
The latter part of your question is an articulate expression why such research probably will never be done. (Either you're a smart guy or our minds work on similar tracks. Maybe both.) I very much doubt there will ever be formal research on this. Would you spend precious dollars on a study to determine more precisely the risk someone will be struck by lightning or killed by a meteorite?



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