[Question #5387] HIV/STI risk assessment & PEP

21 months ago
HI Doctors, 40yr old male here. I recently had an encounter with a female CSW in Cabo San Lucas, Mexico. I had a condom failure for about 3-5min (head of circumcised penis exposed insertive vaginal).  She brought and insisted on the condom to which I was happy to oblige.   Not a streetwalker but from an agency. I asked her if she was limpio "clean" to which she replied 100%.  Then asked me if i was clean to which I replied 100%. She was on the younger side 20 or so and stated she was new to this work.  She also stated she had no sickness and was tested by the "agency"(through google translate). She was very pretty and very clean.  She seemed freaked out. I freaked out. I am getting married in 3 wks!! Right or wrong I took 1g Azithromycin and 800mg of Cefixime the next day (at least thats what the labels said not completely convinced they were legit).  At the airport I did a quick video call with a US doctor who prescribed PEP (Isentress/Truvada). once back in the states I was able to take the first dose at 42hrs.  5 days later I took a Trich/Gono/Chlam urine test to which all 3 were negative. I don not have any symptoms of STI's at 7 days today. Maybe a sore throat on day 3 and sinus pressure that seems to be resolving I think I have a cold from all the travel.
Questions:
1. What was my HIV risk given the region I was in? does the 1/2000 still apply? how about with the PEP @42hrs? any difference?
2. What is my Syphillis risk given the region? I am on the lookout for a chancre but when would it normally appear?
3. Was my test for Trich/Gono/Chlam accurate at 5days even with the use of antibiotics?
4. Would you have prescribed PEP in this situation? Is there any data that suggests at 42hrs its more of a placebo than anything?
5. Would ARS symptoms be lessened while on PEP? or if PEP failed would they just sort of all come roaring at the end of therapy
6. If you were me is the risk low enough to move on?, since testing for HIV is basically 8wks out due to the PEP?
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
21 months ago
Welcome to the forum. Thanks for your question.

My first thought is that it sounds like your partner is very unlikely to have HIV. I would not have recommended PEP against HIV in this situation. That said, I don't know the details of the epidemiology of HIV in that part of Mexico, which conceivably could change the risk assessment -- but I have not heard anything alarming about that area. 

Harder to be confident about other STDs, which are more common. That said, it would seem she indeed is tested frequesntly and probably she wasnt infected. As for your symptoms, they do not concern me at all There are no STDs that cause sore throat or sinus pressure. I agree a common cold is by far the best bet.

To your specific quesitons:

1,4) The average risk of HIV transmission, female to male, for a single episode of unprotected sex, is pretty much the same everywhere. (The currrent estimated average is 1 chance in 2,500.) I do not agree with the decision to take anti-HIV PEP in this circumstance. But once someone has started PEP under a physician's advice, any change -- e.g. a decision to continue or stop, when to be tested, etc -- are between the patient and that doctor (or the patient's own doctor). But I don't think there's anything wrong with the stanard 72 hour limit for the window for effective prevention; PEP after 42 hr is not merely a placebo.

2) Probably zero risk for syphilis; and if exposed, the cefixime (and perhaps the azithromycin) would have aborted the infection before it got started. You cannot now have syphilis and do not need any testing for it. You cannot ever develop syphilis or a positive blood test for it from this evetn.

3) If the test was negative for gonorrhea and chlamydia, then you don't have it now. Most likely you never had either one. But if you did, it was gone by the time of the test and you don't need any further testing. There is no chance you have it now or could infect your fiancee/wife. Apparently you were not treated for trichomonas, but the risk for any one exposure is extremely low and you can rely on the result, which almost certainly will be negative.

5) Nobody ever gets ARS symptoms while on PEP.

6) Now we're into the major downside of using PEP in this situation -- something for you to discuss with the prescribing doctor or your physician. Almost all experts believe that if PEP fails to prevent HIV, it might delay positive blood testing by 3 months. Some even recommend a final test as late as 6 months. Unfortunately, there is no research on this -- just expert opinion. In any case, if you continue PEP, you'll need to wait until at least 3 months for conclusive testing. That's the downside I'm referring to:  instead of highly relialbe results at 4 weeks and conclusive ones 6 weeks after exposure, with PEP the period of uncertainty and anxiety is extended to 3-6 months. As implied above, this is something for you to discuss with the prescribing doctor:  I have no advice about it.

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

HHH, MD
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21 months ago
Thank you very much for the clarification on the ARS and PEP! There isn't much info out there for that specifically. That was indeed helpful and hope it is for others looking for correct info! I will indeed follow up with the online physician on whether or not to stay on PEP. (FYI No side effects so far).
Just a couple of follow ups and I'm done.
1. Your analysis on PEP in this situation is based on the low risk correct?  ie.  not anal or MSM?
2. Just looking at other questions the 1/2500 transmission rate you mention is with a person who has HIV correct? So the odds that she did not have HIV would decrease the 99.96% (1/2500) chance of transmission even further? and also the PEP would factor in somewhat but I know there is not a whole lot of data there. 

Thanks again for the prompt and informative replies. Lesson learned here! (even with the best intention ie.  proactively using condoms). 
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
21 months ago
1. Risk assessment is always the only basis for deciding for or against PEP. Based on what you said, I think your risk was too low to need it. But as noted above, I don't know enough about the frequency of HIV in women like your partner in that geographic area. 

2. Correct, the statistic is for sex with an infected partner. The actual risk depends on the chance she was infected. For example, if 1% of women in that setting have HIV, your risk of infection would be something around 1 in 250,000.
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21 months ago
Thank you again for the further information.  Update and additional info:

I spoke with the online physician who prescribed the PEP and his advice was it was ultimately my decision but had the same reservation on the unknown epidemiology of HIV in that area of Mexico. 
With that information, I did some research on my own and I found UNAIDS.org stated that although Mexico as a whole does not have a particularly high prevalence of HIV, the CSW category as of 2016 "Sex workers with an HIV prevalence of 7.0%" (does not delineate male/female or gay/straight) .  This seems scarily high to me! Another article states this number may be restricted to borders areas but not sure how accurate that is. So my last question is:

Do you think that percentage could be accurate? If so might your original risk assessment change on PEP use?

As this is my last follow up ,Thanks again for the straight facts and expertise as they are truly priceless for someone who is a complete mess right now with an upcoming wedding.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
21 months ago
While I applaud your research for relevant data, you have to be cautious about sweeping conclusions about HIV statistics, especially for an entire country. I imagine 7% of a certain localzed group of female sex workers in Mexico might be infected. However, if that were the national average, it would make Mexico among the highest in the world for sex worker HIV rates, competing with some countries in sub-Saharan Africa. I can't believe it applies to all female sex workers in that country. And you gave good reason to believe your sex worker partner is even lower risk than average. If somehow I had been your situation, I definitely would not have sought PEP.

Thanks for the thanks. I do hope the discussion has been helpful.
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