[Question #11024] Risk of HIV/ STDs from Sexual Assault
17 months ago
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Hello doctors,
I tried to give you a in depth description of what happened but it was too long. 5 days ago I was sexually assaulted. I didn’t think anal sex (or any really) was going to happen from this encounter but the person ended up getting inside of me for 2-3 thrusts before I pushed him away and was able to get out of there. No condom because I never expected it to get there but I don’t think he came inside me either. He told me he had never been with a guy before at one point but I don’t know if that’s true. This is not something that ever happens to me. I have been in a monogamous relationship for more than 2 years and I haven’t had any risky sexual encounters in more than 8 years. I went to the ER and they tested me for stis and hiv (all negative) and gave me pep and doxycycline to take (which I have been). I took my first dose 57 hours after.
1. What is my risk of HIV from this encounter? I am worried sick. I don’t want my relationship to end or change from this incident
2. What are my risk of other STDs from the encounter?
3. When can I feel like I am going to be okay?
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H. Hunter Handsfield, MD
17 months ago
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Welcome to the forum. Thank you for your confidence in our services.
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I'm sorry to hear this history; I understand entirely how stressful the situation must be for you -- perhaps more because of the assault itself than the potential STI/HIV risk.
Based on your description, I would put the risk of HIV or other STIs as being quite low, even if the assailant has untreated HIV or other STIs. As you likely know, receptive anal sex is the highest risk sexual exposure for HIV, but even this has no higher than a one percent chance of HIV transmission if the insertive partner has HIV. With such a brief exposure and no ejaculation, the risk undoubtedly was much lower than this. So let's say maybe one chance in a thousand? And that's if the guy has HIV; so if we assume a 10% chance he IS infected, your risk could then be estimated at one chance in 10,000. That's equivalent to having such exposures once daily for up to 27 years before being infected. The risks of other STIs like gonorrhea, chlamydia and syphilis were a lot higher, however.
I'm guessing the ER docs would have given you similar reassurance -- but of course that depends on their personal knowledge of the risks and probabilities. In this situation, I agree that both PEP and doxycycline prophylaxis were warranted and I'm glad you received them. Doxycycline need only have been a single dose of 200 mg, although it sounds like maybe you were prescribed several days of it. The first dose or two protected you nearly 100% against syphilis and chlamydia, and was about 50% protective against gonorrhea. The PEP will be at least 90% effective in preventing HIV -- bringing the chance have HIV down even further, to maybe one chance in a hundred thousand. Pretty good odds!
Those comments answer questions 1 and 2. As for no. 3, you can be completely confident right now about chlamydia and syphilis. To be certain about gonorrhea, you could have another rectal swab test any time more than 2-3 days after the assault, at which time another negative test result would be conclusive. Doxycycline is so reliable against syphilis that you don't even need a follow-up blood test, although you could do that after about 6 weeks if the negative results would improve your confidence about it. For HIV, the usual recommendation is to have an AgAb (4th generation) blood test 6 weeks after the last dose of PEP. Earlier negative testing, if advised by the ER or your own doctor, would be reassuring but not quite conclusive.
I hope these comments are helpful. Let me know if anything isn't clear.
HHH, MD
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17 months ago
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Thank you for your reply. That definitely has helped. Here are my follow ups
1. I really do not want to tell anyone about this. I want to forget about it as much as I possibly can and resume my life as I was living it. However, what is the risk to my partner if we were to be intimate since I am on pep? I am trying to avoid it..but I just want to know because it’s not going to be easy
2. At the ER, which was 2.5 days after the incident, I was given shots of penicillin and another antibiotic as well, and I got a rectal swab test for gonorrhea and it was negative. Was that test conclusive?
Thanks again for your help. I just want to know if I should be worrying like I am or not. It’s enough to have it happen, let alone now worry what could come of it. I just want to try and put it past me and live my life
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H. Hunter Handsfield, MD
17 months ago
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1. There is little or no risk of HIV transmission while on PEP. And very low risk you caught HIV anyway, as discussed above. If somehow I were in your situation, I would continue unprotected sex without worrying I could infect her (or him) with HIV or any other STI from this event. That said, I'll note that although this forum doesn't generally offer relationship counseling, many or most persons in your sitution benefit from discussing events like this with their partners, especially if the relationship is inherently strong.
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2. The penicillin was to prevent syphilis (although it was superfluous when you were also going to take doxycycline), and the other shot undoubtedly was ceftriaxone to prevent or treat gonorrhea. Your negative gonorrhea swab was conclusive: you can be sure you didn't get it. There is no need to test again for gonorrhea, chlamdia or syphilis -- only HIV.
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