[Question #7285] Oral STDs and Testing

5 months ago

As you’ve been incredibly helpful in guiding all of us through both understanding and moments of anxiety, I wanted to pose a general question that I hope helps to inform others about the subject topic, as it seems like there is a lot of conflicting information out there.

I realize that there are a multitude of STIs out there, but it seems like few, if any, are worthy of testing for orally, except in specific situations.  I’ll put these in buckets, as I think it might help make this more focused.

1). For the “lesser” STIs (mycoplasma, trich, etc.), I’m not sure if these are orally transmissible, and also not sure if you can test for them.  Thoughts?

2). For herpes, I guess you could test for it, but perhaps there isn’t a great deal of value in doing so, as it is so common (type I or II), other than to inform you that you have it.

3). For HIV (difficult to transmit orally) or syphilis, I would assume that a standard blood test done for a genital HIV/syphilis screen would pick up both, so oral testing isn’t needed.  Thoughts?

4). Which leaves both chlamydia and gonorrhea, which seem to be the risks to manage.  I’ve read that both infections “clear themselves” over a period of time.  If that is so, could you advise as to how long?  Furthermore, unless you believe you are symptomatic, is there any real reason to test for these as part of a regular testing protocol, assuming that they can’t (or very rarely) “infect the rest of your body”?  Lastly, can you speak a bit about the transmissibility of each, both via kissing or oral-genital?  If what I’ve surmised from various articles is correct, assuming that oral infections clear themselves, there is probably only a few week window when an active oral infection is present when it can be spread, so not much to worry about unless you have frequent sex with multiple partners.

Thanks for your comments and guidance.
Edward W. Hook M.D.
Edward W. Hook M.D.
5 months ago
Welcome back to the forum. Thanks for your questions. Certainly STI‘s can occur following either performance or receipt of oral sex. That said, it is always important to realize that most people do not have STI‘s and, that when they do, oral infections are less common than genital infections and are less efficiently transmitted from person to person. There are many previous discussions of oral STI‘s On the forum and I would encourage you to scan previous posts for information as well as considering my specific responses.  In response to your specific questions:

1.  Most currently available tests do work fairly well when used in the oral cavity although they have been well as well studied as tests for Gonorrhea and chlamydia.  Trichamonas is not a meaningful cause of oral infection and is not know to be transmitted by oral sex.  M. Genitalium is occasionally detected in persons performing oral sex on infected partners but is rare.  

2.  HSV-2 is an extraordinarily rare oral infection.  OTOH, over 60% of adults have HSV-1 although fewer than one in five persons withoral HSV-1 know that they have it.  Blood tests for HSV-1 are notoriously unreliable and not routinely recommended.

3.  Correct.

4.  Most oral Gonorrhea and chlamydia oral infections are asymptomatic.  When persons feel that they are at risk for oral STIs due to oral exposures to potentially infected persons, screening oral tests are recommended as good practice. The time course of clearance is not well described and is a subject of ongoing research.  In general, STIs are less efficiently transmitted than genital infections.

Regarding kissing, there are a small group of investigators who believe that gonorrhea can be transmitted from person to person through kissing however most experts feel that this is a rare event and not a major concern.

Hope these responses are helpful.  EWH
5 months ago
Thanks for the responses.  Helpful context and guidance.

To clarify your response on my question #4, I’m curious if you could opine on the following:

1). Should sexually active persons get regularly tested for oral STIs in addition to routine “genital” testing (standard STI blood/urine tests)?  Asking because I’ve not known anyone who does so or has been advised to do so.
2). Assuming that someone tests negative for STIs per routine “genital” (non-oral) testing, do you see any reason to also request a test for various oral STIs?  I’m curious to hear your thoughts here, as many general practitioners or other clinics that administer testing aren’t subject matter experts, and I’ve heard mixed opinions.  Also, as you’ve noted, if most oral gonorrhea/chlamydia infections don’t yield symptoms, just curious if it’s even worthwhile to test periodically or when you have a new relationship/partner, given that the transmission risk is likely lower.
3). Lastly, are you aware of oral infections spreading within the body?  Have read that oral gonorrhea or chlamydia, for example, if left untreated can spread throughout the body and infect you elsewhere, but wasn’t sure if you had an opinion on this or the relative likelihood.

Again, thanks for your responses.  Wanting to be responsible to myself and others.
Edward W. Hook M.D.
Edward W. Hook M.D.
5 months ago
Good questions.  Straight to the replies:

1.  This question gets into the general overall category of how often persons should be screened, that is tested in the absence of symptoms for STI‘s. In general, if a person has multiple partners or has partners who may have other partners, it is advisable to periodically be tested for STI‘s which are all too often asymptomatic. In men STI‘s are more commonly asymptomatic at the throat or, if one receives receptive rectal intercourse, the rectum then at urogenital sites. On the other hand any potentially exposed site can be infected.  studies of persons who regularly engage with new partners and have both unprotected oral and genital sexual exposures, between 25 and 40% of infections are present only in the throat. Thus if you are exposed at a site, that site should be tested. How often it should be tested depends on your own assessment of your risk and just how many partners you may have over a given time period.  

2.  I believe this question is answered above.  The only STIs I would routinely test for in the situation with the gonorrhea and chlamydia.

3.   STI’s are transmitted through direct contact and, in general with very, very rare exceptions, STI’s stay at the site of infection. Thus genital infections stay at the genital  location and oral infections stay in the pharynx.  They do not spread throughout the body. 

I hope this information is helpful. Just a heads up, you have one additional follow-up question after which this thread will be closed. EWH
5 months ago
Thanks for the comments.  Very helpful.

For my last question, I wanted to ask about the relative likelihood of transmission of gonorrhea or chlamydia for various oral acts.  As such, can you please share what data and opinions that you have about relative transmission (ie - very high, low, very rare, %s, etc.) of each?  From what I’ve read, it seems like fellatio carries the highest risk, but I’m not sure about the validity of that information.  I’ve also read that transmission from cunnilingus is rare (due to lower likelihood of member or fluid contacting pharynx versus fellatio and/or lower concentration of gonorrhea/chlamydia in vaginal secretions), but again, I don’t know if that is accurate.  And I know very little about #3 below, but good to know for completeness.

What are transmission risks by type of oral sex?

1). Cunnilingus
2). Fellatio
3). Oral-anal (rimming is I believe the correct term, but am not sure)

Thank you for educating not only me, but also the rest of the forum.
Edward W. Hook M.D.
Edward W. Hook M.D.
5 months ago
Of the three sorts of exposures you mention, clearly fellatio is highest risk for acquisition of Gonorrhea or, less commonly, chlamydia.  Rimming and cunninlingus are both lower risk exposures but whether one of the other is highest risk is hard to say.

Hope this helps, end of thread.   EWH