[Question #6043] Unprotected Sex Risk

17 months ago
Last night I had unprotected sex twice with a new partner. Before doing it I asked if I needed to worry about anything and he said I did not. I don’t believe he has ever been tested but he has no symptoms of anything and hasn’t had sexual encounters for many months. 

I am curious about the likelihood of contracting and STI after just two encounters with someone who shows no symptoms.   Also, how long should I wait prior to getting tested. I have seen numbers anywhere from 3 days to 3 weeks for the three most common STIs. 

I have also had oral sex (different person) off and in for the past few months. What is the risk of passing something to him from this encounter if he were to give me oral again? What about the risk if we were to have unprotected vaginal sex? 

I was married for many years prior to these encounters and I feel ashamed of the questions and nervous about my risks. 
Edward W. Hook M.D.
Edward W. Hook M.D.
17 months ago
Welcome to our Forum and thanks for your confidence in our assessments.  Please do not be ashamed to being asking these questions- they indicate that you are taking appropriate steps to preserve your sexual health- that's nothing to be ashamed of.  In fact, I congratulate you as well for asking your partner about his status.  Good work! 

The three most common treatable STIs are chlamydia, gonorrhea and trichomonas.  Tests for gonorrhea would be positive if you had become infected by 2-3 days after exposure.  On the other hand, chlamydia grows a little slower in the body and thus in testing for these three infection, you can anticipate accurate results with any test taken a week or more after exposure.  There are other, less common STIs which may take longer for tests to become positive.  Typically tests for HIV are not conclusive until 6 weeks after exposure and tests for syphilis may not be positive until 4 weeks after exposure.  

As far as we know, infections are transmitted about equally often whether a person is symptomatic or not.  

The risk for STIs from receipt of oral sex (cunnilingus) is low and infections are quite uncommon.  So low that here are not specific estimates of how often this occurs.  If you were to perform oral sex on an infected man, there is a risk of acquiring gonorrhea from such an exposure and a very, very low risk of acquiring chlamydia.  If you perform oral sex on new partners or partners who may have had other recent sex partners, my advice would be to get a throat swab for gonorrhea and chlamydia at about the same time you get screened for genital STIs.

I hope the information I have provided is helpful to you.  If there are further questions, you may ask up to two additional follow-up questions.  EWH
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17 months ago
Thank you for your response. What is the likelihood of contracting an STI after two encounters?

Also what is the risk for the man giving me oral sex if I have been infected?  How likely is it that he will contract something from me? 
Edward W. Hook M.D.
Edward W. Hook M.D.
17 months ago
Precise estimates of per encounter risk are not available for most STIs.  there are data for gonorrhea which suggest that after a single encounter with a man with gonorrhea, about 4 out of 10 women will become infected.  After 3 encounters about 8 our of 10 will be infected.  After two times would be somewhere in between.  It is presumed that the risk for chlamydia is about the same.  

Men performing oral sex on an infected women very, very rarely get infected but there are not good estimates.  It is not something I would worry about.  EWH
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