I am uncircumcised male in US. Today I had protected sex with a csw. And when we switched position to 'doggy' I think the condom broke when I was trying to insert. For me, I obviously felt that I touched her body with some fluids but I am not sure whether it was fully inserted, becuase she was tight and I was just trying to put it. For her, she mentioned that I didn't insert at all (you were just poking around) and when she noticed the sound of breaking, she stopped me immediately. The worst case scenario is that I had unprotected sex for ~1 second. 

The csw is a part-time high-end csw from Taiwan. She claimed to have never worked as csw before and always wear condoms. Obviously, I can't verify the truths. 

In this case, do you recommend PEP for HIV? I am not too concered for other STIs since they are curable and easily treatable. 

Thanks!

I really don't think you need to be worried. I certainly do not recommend PEP, at least not based on the information you provide. Even testing for STIs is optional; if somehow I were in your situation, I would not be tested for anything. 

The details:  First, at any point in time, even among the highest risk CSWs, most do not have an active, transmissible STI, and certainly most do not have HIV. This is particularly true for most "high-end" female sex workers, who tend to take care to protect themselves (condoms), have low risk clients (men like you!), and get tested frequently. And with your partner apparently new to the game, she may be even lower risk than most. Second, STIs are inefficiently transmtited -- that is, sex with an infected person usually doesn't result in th infection being transmitted. The actual risk varies widely from one STI to the next:  HPV is present may be transmitted half the time; for HIV, the average risk for unprotected vaginal sex, female to male, is once for every 2,500 exposures. (It usually takes months or years of regular sex with an infected partner before HIV is transmitted.) Other STIs fall between these extremes. Finally, it sounds like your exposure was very brief after the condom broke. The frequencies of HIV and STI transmission just cited assume unprotected sex for several minutes.

So as I said, if I were in your circumstance, I would not feel a need for testing. Rather than testing after any single exposure, a smarter approach for sexually active people with a few new partners each year is annual testing, not worrying about individual event unless symptoms develop. That said, given your worries, probably you should be tested even though your risk is very low:  many or most persons nervous enough to ask these questions feel more reassured by negative test results than by professional opinion, no matter how expert. If you feel this applies to you, I suggest having a urine test for gonorrhea and chlamydia 4-5 days after the exposure, and blood tests for HIV and syphilis at 6 weeks. The HIV test should be an antigen-antibody (AgAb, "4th generation") lab-based blood test.

Finally, one more option to consider. If you are able to contact your partner, you could ask her to be tested for common STIs, especially HIV (plus syphiils, gonorrhea and chlamydia). If her tests are negative, you will know for sure you could not have been infected. And perhaps you would find she is just as nervous about this event as you are. After all, why should she assume you don't have HIV or another STI? If both of you were tested now -- with no need to wait even a day -- you both would know you were not at risk. This could well be the quickest route to the reassurance you seek.

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

HHH, MD

As a note, she doesn't seem to believe she needs to test since she said: I never had unprotected sex. And when I told her I am a scientist (I really am), she seems to not believe it at all... 

Thanks! 

Your partner sounds awfully naive, but it remains unlikely she has HIV.

Thanks!

That completes the two follow-up exchanges included with each question and so ends this thread. I hope the discussion has been useful. Best wishes and stay safe.