[Question #12089] Post-HIV PEP Testing, Paxlovid

10 months ago

Hello, I hope you are all doing well. For background, I am an uncircumcised male within the US who had unprotected vaginal intercourse with a Taiwanese CSW of unknown status also within the US, on 8/1(120pm).

After consulting with a doctor friend, I went to the ER, was prescribed, and took my first dosage of PEP (Truvada/Isentress) 15.5 hours after exposure(8/2 450am).

Completing the 28 day course with no dosages missed, I took an extra? Truvada pill on 8/29. I tested the following days post-PEP.

8/30-Day 1 - Gen IV: Non-Reactive
9/3-Day 5 - Full Panel: Negative or NR
9/12-Day 14 - HIV RNA PCR: NR
9/23-Day 25 - HIV RNA PCR, HIV Gen IV: NR

The reason I took one on day 25 is because I woke up with a fever and sore throat, but this later resulted in a COVID diagnosis, for which I took Paxlovid starting on day 26. I was told that based on my testing, it was 99.5% conclusive and that I should do a GenIV test on Day 30 for conclusive testing. However, due to being sick, I decided to postpone testing until recovery. On 10/10, it would be 42 days post-pep, but I decided to take it on 10/14, which would be 46 days post-PEP. My questions are:

* Would the usage of Paxlovid affect the post-PEP testing window, due to it using ritonavir?

* Based on my testing history and background, is there any reason for me to worry about this Day 46 test?

Thank you.

H. Hunter Handsfield, MD

10 months ago

Welcome to the forum. Thank you for your question.

I'm not sure I would have advised PEP in this situation; your risk of HIV for such an exposure likely was on the order of one chance in a million or lower. But what's done is done. It is now certain you were not infected. There are no drugs, medications, or illnesses known to interfere either with the timing or accuracy of the HIV blood tests, and none that are known to alter the natural course of early HIV. infection. That includes covid-19 and paxlovid. In other words, I have no concern at all about the timing of your test results, the extra dose of PEP.

For many years, common advice for HIV testing following PEP was that a negative RNA PCR test 10-15 days after the last drug dose was nearly conclusive, and that a confirmation AgAb (4th generation) blood test should be done at about 6 weeks (or 3 months, some said). However, with several additional years of clinical experience, almost all HIV experts consider a negative PCR at 11+ days to be sufficient proof. Out of habit or conservative approaches, many still advocate an AgAb test 4-6 weeks after the last PEP dose, but it probably isn't necessary.

Those comments pretty well cover your specific questions, but to be specific: no, I don't think the paxlovid/ritonovir had any significant effect, because your negative RNA PCCR on day 14 proved you didn't catch HIV. And therefore, I also do not have the slightest worry about your 46 day test a few days from now. It will be negative.

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

HHH, MD

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10 months ago

Thank you for your response, Dr. Handsfield.

The information you have provided was most helpful, and definitely reassuring to any lingering anxiety I might have had.

Thank you for the time, and I hope all is well for you. Have a great day!

H. Hunter Handsfield, MD

10 months ago

Thanks for the thanks; I'm glad to have helped. I'll leave the thread open a day or two in case related questions or issues come to mind.---