Congratulations for having safe sex. Too bad the condom broke, but it happens sometimes.

You are correct that the odds are in your favor -- overwhelmingly so. That the exposure occurred in Thailand slightly elevates the risk compared with, say, western Europe or the United States, because of differences in the likelihood a sex worker has HIV. Still, HIV has been dramatically controlled in Thailand compared with 10-20 years ago, and there probably is under a 1% chance your partner had HIV. And even with entirely unprotected sex, the average HIV transmission rate from vaginal sex averages around once for every 2,000 exposures -- and your risk was a lot lower than that, given the brief exposure after the condom broke. All things considered, I would calculate the chance you caught HIV at under well under one in a million.

Decisions for post exposure prophylaxis (PEP) are always best made on a case by case basis, and with understanding of details of risks in the immediate geographic area. Although my analysis above suggests a very low risk, perhaps the doctor or clinic where you were treated has more detailed knowledge suggesting higher risk; or perhaps for entirely unprotected sex. Decisions for PEP are easier than they once were, given the low toxicity and side effects of the drugs. Still, it's not a decision to be made lightly and I doubt I would have prescribed it in this situation. And there is another downside to PEP that you and the doctor might not have considered:  without treatment, you could have a conclusive 4th generation (antigen-antibody) HIV test 4 weeks after the event. With PEP, positive blood test in theory might be delayed if treatment doesn't work, and it is recommended that testing needs to be extended to 3 months. So if you continue PEP, you're looking at an additional 2 months of uncertainty, perhaps worry, and avoiding sex other partners.

But I cannot make the decision for you and I am not recommending you stop PEP. This is something to discuss with a physician in person, ideally the one who prescribed it.

I hope this has helped. Let me know if anything isnt clear. Best wishes and stay safe--  HHH, MD

There are no data at all on the effect of brief courses of PEP -- i.e. early cessation of planned one month treatment -- on delaying HIV test positivity. I suspect an antigen-antibody test would still be conclusive 4 weeks after exposure. However, despite your kind statement about my and Dr. Hook's expertise (thank you), I'm really not a true HIV testing expert; my expertise is greatest in non-HIV STDs. The doctor treating you (apparently an infectious diseases specialist?) may have more experience with HIV infected patients and HIV testing than I do. Don't hesitate to ask; you could even consider printing out this thread as a framework for discussion.