I posted yesterday and agreed with the risk assessment Dr. Hook kindly provided. Here is the situation: Yesterday, after the vaginal sex, I could feel that the condom did not cover my penis all the way to shaft. The CSW tried to hold the condom to make sure the ejaculate did not come out. After she gradually moved out my penis, I could see my penis not covered by condom and the condom was in her hands. To be honest I am not so sure why it happened. She told me the condom did the job. We confirmed that the ejaculate was in the condom. I read through all your related answers on Medhelp and here, and I understand it is an extremely low risk situation because: 1. the probability of the female CSW (22 year-old, high-end, Asian in USA, says she gets tested twice a year) is probably lower than 1 in 1000.  2. The transmission rate of female-to-male unprotected sex is 1 in 1000 (I am uncircumcised). So the probability of me getting HIV is less than 1 in 1 million. 3. When the condom did not cover the head of penis, it usually went deep inside the vagina. And both of us could feel it. While I understand it is an extremely low risk event, I am still worried what if some parts of my foreskin were not covered? I talked to the PA of my PCP and surprisingly, she agreed to give me PCP, which is a generic version of Truveda. I took the first pill 28h after the event. My questions are:1. does it make sense for me to take PEP? I can stop it anytime. I think I took it mostly to ease my anxiety. 2. Is Truveda itself enough to be effective if taken as prescribed? 3. Will it lengthen the window period? Thank you!

If I were you I would have never taken PEP and see little reason to continue. Regarding why the clinician you saw provided PEP, unfortunately, it is a simple fact that when patients are requesting therapy the path of least resistance is to give the drugs, even if it is not necessary. I suspect this is what happened in your case.

EWH 

Thanks for your responding. I think I took it out of anxiety, guilt, and unreasonable worry. Since I actually never had exposure, I am not too concerned that the PEP will make the window period longer. However, I agree that I see no reason to continue. If I only took one pill and I stop, will it still lengthen the window period? Thanks!

What I didn't realize is the potential side effects of PEP. I think for me or others who have smilier exposure, the probability for us to have all the short-term and long-term side effects, both known and unknown, (I work in healthcare and understand that it is impossible for us to know all the side effects a medicine can have) is much larger than the probability to get HIV. Do you think it is a reasonable rationale? 

I also talked with the CSW and she confirmed that the condom was covering my head of penis. (It is obviously at her best interest to make sure of it). All things considered, I would stop after I took one pill of Truvada. Thank you very much for your understanding, patience, and professional knowledge. Best wishes to you and please keep helping persons like me to understand the medicine.