[Question #3909] Oral Transmission of STDs

34 months ago
Hello doctors,

I recently had a single encounter with a 20-something professional white woman after an evening of drinking at a bar about 2 days ago.  I do not know her STD status, but she did not show any symptoms visibly. I do know many STDs are asymptomatic though. During this encounter, there was mutual masturbation, and I performed oral sex on her for approximately 3 minutes. I never ejaculated, she did not perform fellatio on me or have any direct penile-vaginal contact, and I did not have any open cuts/sores/or wounds. I get tested regularly and have thus far contracted nothing.

My questions are these:

1) What is the likelihood that I received pharyngeal gonorrhea or chlamydia form this exposure, or any of the other potential STDs for that matter (such a syphilis or HIV)?

2) Because I know I worry too much about these things, I am going to request a throat swab at a clinic regardless of my chances for piece of mind. How long should I wait until I can have a reliably accurate swab of my throat taken?  I know I need to wait a number of weeks to test for syphilis or herpes, but I'm curious mainly about a throat culture.

3) If I find myself in another intimate situation in the near future, how likely is it that I transmit an STD by kissing or performing cunnilingus again. Again, I am mainly concerned about gonorrhea and chlamydia, but would appreciate any insight you have about the other diseases as well.

Sincerely and thanks,
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
34 months ago
Welcome to the forum. Thanks for your question.

You really needn't worry -- the chance of any infection was extremely low. You could get tested if you would find the negative results reassuring, but it's optional. If I were in your situation, I would feel no need and would continue unprotected sex with my wife without worry.

1) Oral sex is safe sex, with a low risk of all STDs (much lower than unprotected vaginal or anal) and virtually zero risk for some. Cunnliingus (oral-vaginal contact) is especially safe, with very low chance of gonorrhea, chlamydia, or anything else. Syphilis is theoretically possible in this situation, but extremely unlikely. And there has never been a documented case of HIV transmitted by cunnilingus. All in all, I would put the chance you were infected with any STD at less than 1 chance in many thousand.

2) A pharyngeal (throat) swab for gonorrhea is fine. You might have trouble finding a lab that will do a chlamydia test; testing for oral chlamydia is generally not recommended. There is no other STD testable by this method. A throat swab for either of these is valid any time more than a few days after exposure. You correctly understand that blood tests for syphilis and HIV should wait until 6 weeks after exposure.

3) Kissing never transmits STDs, or so rarely that it can be ignored. Cunnilingus is more or less the same. (The greatest transmission risk would be if you have oral gonorrhea and perform fellatio on another male.)

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD
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34 months ago
Thank you for the quick reply, Dr. Handsfield.

That was pretty clear and about what I expected to hear. Doing my own research on the subject gave a bunch of conflicting opinions about where exactly pharyngeal chlamydia or gonorrhea resides in the mouth or throat, and in turn how easily transmittable they are in various circumstances, so your advice is very useful.

  I'll be setting up an appointment today or tomorrow then to get that swab.

Again, Thanks.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
34 months ago
Indeed there is conflicting information online and elsewhere on these issues, especially in regard to chlamydia. But "information" is a broad area, and much of what you can find is based on assumptions ("If it applies to gonorrhea, it probably applies to chlamydia"), habit (no change in advice with evolving research and expert recommendations), or misunderstanding of the available data.

As suggested above, it will be extremely surprising if your test is positive for oral gonorrhea or chlamydia. But let me know the result when available.  But please no other comments or discussion until then, since the forum standard is that we respond to only two follow-up comments or questions.

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34 months ago
So I went in to get a throat swab today and the clinic doctor told me that a test swab in the throat couldn't be taken if asymptomatic.  I disagree with him, but I'm also not a doctor.  

He did simply give me a regimen of antibiotics (4 pills and a shot) and treated me as though I had it, which I also found strange.

On one hand, I don't know how comfortable I really am taking antibiotics prophylactically, but on the other hand, I definitely do have piece of mind now.  In the very likely event I got anything, it's gone now.

Anyways, thanks again Doc!
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
34 months ago
You obviously found a doctor who doesn't understand STDs well:  I agree with your disagreement with him! The vast majority of oral gonorrhea or chlamydia cause no symptoms; if testing were limited to people with sore throats or other symptoms, the large majority of infections would be missed.

The risk you were infected was extremely low, as I said above, and if you were my patient, I would not have treated you. However, I'm glad it has given you peace of mind, and it probably will do no harm. It sounds like you got the right regimen: ceftriaxone (the shot) and azithromycin (the 4 pills). They will reliably eradicate either gonorrhea or chlamydia if you were infected. In addition, they will prevent syphilis if you were exposed (which also is very unlikely).

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