Can I get Chlamydia From Oral Sex?

Chlamydia. Science Picture Co./Collection Mix:Subjects/Getty Images

Chlamydia is a somewhat strange organism, not quite a bacteria and also not quite a virus. One of the most common sexually transmitted diseases around the world, it is a leading cause of both preventable blindness and preventable infertility, and yet the fact that it is often asymptomatic means that people can be infected with it and not know for years. That combination of factors is why chlamydia is one of the few STDs that many doctors regularly screen for, at least in young women.

However, the standard urine and swab screening tests for chlamydia only detect penile and vaginal infections. They don't reliably detect rectal chlamydia, and they also don't detect chlamydia that has been spread through oral sex - leading to an infection in the mouth or throat.

In the spring of 2015, a large research study set out to examine how common non-genital chlamydia and gonorrhea infections were in an urban U.S. population. It turned out that they were far more common than most people would expect. Almost four percent of women and 1.6 percent of men who have sex with women were infected with extra-genital chlamydia, and so were almost 12 percent of men who have sex with men(MSM). For women, that meant that more than 13 percent of chlamydia infections wouldn't be detected by standard screening techniques. Without significant changes in screening protocols, they might never be detected at all, except in an unusual circumstance where one partner is diagnosed with chlamydia, the doctor can't find a genital infection in the other partner, and they decide to do a more in-depth search for how transmission might have occurred.

Fortunately, as chlamydia is spread through secretions rather than skin to skin, it is possible to greatly reduce the likelihood of transmission during oral sex. Condoms can be used during fellatio, and dental dams or other barriers can be used during rimming or cunnilingus. Having protected oral sex can also reduce the likelihood of transmitting a number of other STDs, including human papillomavirus (HPV), where oral infection can potentially lead to oral cancer.

How This Information Will Affect Screening Behavior

All things considered, I suspect it's relatively unlikely that most doctors will begin to regularly test for oral chlamydia anytime soon, except possibly in sexually active MSM -- where there is an existing three site screening recommendation. However, if you regularly have unprotected oral sex, it's a good idea to discuss that fact with your doctor -- particular if one or more of your partners has ever been diagnosed with an STD. That way, your doctor can help you decide if screening for oral STDs is a good idea. 

Unfortunately, while in an ideal world doctors would ask you these questions unprompted, there's a good chance that you won't end up talking about most sexual risk factors with your doctor unless you bring them up. After all, doctors are people too and, like many people, are often terribly uncomfortable talking about sex.


Mylonas I. Female genital Chlamydia trachomatis infection: where are we heading? Arch Gynecol Obstet. 2012 May;285(5):1271-85.

Trebach JD, Chaulk CP, Page KR, Tuddenham S, Ghanem KG. Neisseria gonorrhoeae and Chlamydia trachomatis Among Women Reporting Extragenital Exposures. Sex Transm Dis. 2015 May;42(5):233-9.

Zakher B, Cantor AG, Pappas M, Daeges M, Nelson HD. Screening for gonorrhea and Chlamydia: a systematic review for the U.S. Preventive Services Task Force. Ann Intern Med. 2014 Dec 16;161(12):884-93. 

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