[Question #9625] Did not complete PEP. How does this affect testing windows?

30 months ago

Hi there,

Thank you so much for providing this service.

I was prescribed Biktarvy for PEP after a potential HIV exposure on November 2nd, 2022. My exposure was from receptive oral sex with another man, and the doctor suggested PEP because I had brushed my teeth immediately before the exposure, my gums had bled and my partner ejaculated in my mouth.

I unwisely did not finish the full round of Biktarvy that was prescribed. I know how stupid that was and I regret it but cannot change it now. Will the pills I took cause significant delay in the testing window?

PEP timeline:

Nov 2nd, 2022: Potential exposure

Nov 3rd, 2022: Started PEP (Biktarvy)

Nov 11th, 2022: Took my final PEP pill and discontinued treatment (9 pills taken total)

I'm coming up on 3months post exposure and will test again then, and again at 6months. I've already tested a couple times due to my anxiety and am wondering if any of the tests I’ve taken thus far can be considered a good indication of my status, or if the 9 days of PEP pills I took have significantly changed my testing window?

I’ve taken the following tests thus far:

January 2nd, 2023: HIV 4th Gen Antibody/Antigen Test (came back negative) - this was 61 days post exposure and 52 days after last PEP pill.

January 10th, 2023: HIV RNA test (came back negative) - this was 69 days post exposure and 60 days after last PEP pill.

Thank you again for your insight.

H. Hunter Handsfield, MD

30 months ago

Welcome to the forum. Thank you for your confidence in our services.

No data exist on the effect of partial PEP on time to conclusive HIV testing. However, even after a complete course of 28 days, the HIV AgAb (4th generation) blood tests are conclusive 6 weeks after the last dose; and of course there is no reason to suspect that a shorter course would be any different. Accordingly, your negative AgAb tests 52 and 61 days after your last dose conclusively showed you do not have HIV. The RNA test at 60 days was unnecessary, but confirmed the previous results.

In addition, you had a very low risk exposure. I agree with the doctor who prescribed Biktarvy that tooth brushing and gum bleeding might have increased the risk of HIV from that exposure. However, the risk was almost zero to start with: IF your partner had HIV (and apparently you do not know he did), the risk of receptive oral sex for HIV transmission -- i.e. penis to oral -- has been estimated by CDC at once for every 10,000 exposures. That's equivalent to such exposures with infected men once daily for 27 years before it is likely someone would acquire HIV. Even if you double that risk because of tooth brushing etc, it's still a very low risk. Had I been your doctor at that time, I would have strongly recommended against PEP because your risk was too low.

Anyway, from your test results you can now be 100% confident you did not acquire HIV. No further testing is necessary at 3 months, 6 months, or any other time. Don't waste your time, money, and energy on it. All is well.

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

HHH, MD

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30 months ago

Thank you for your answer, I appreciate the time and thoroughness. To clarify on my end, I've only had one 4th gen ag/ab test, which was 52 days after my last pep dose (aka 61 after the exposure) -- these were not two separate tests, I just worded it confusingly. But I take your point that after 6 weeks the results are conclusive.

My anxiety stems from me being symptomatic the past couple weeks -- night sweats, severe dry mouth, body aches, rashes. I know those symptoms can be attributed to a number of things other than HIV but it has been anxiety-inducing nonetheless. In the event that these symptoms are due to HIV/seroconversion, would an ag/ab test be able to detect that at the onset of symptoms? Your response has helped calm my nerves but I may take one final test soon for my own sanity.

All best, and thank you again.

H. Hunter Handsfield, MD

30 months ago

Two aspects about AgAb test performance are relevant here -- closely related to one another, but still distinct. First, is HIV infection present or not? For that 6 weeks is conclusive, although some experts recommend final testing as late as 3 months after the last dose of PEP. Personally, I am confident this is overkill and unnecessary; I've never heard of anyone testing negative at 6 weeks and later positive.

The second aspect concerns symptoms. It is impossible to have symptoms of acute retroviral syndrome (ARS) or AIDS and have no detectable antibody. It is not HIV itself that causes symptoms of ARS, but the immune response to the virus -- and that is reflected in the antibody test. Your negative test proves with 100% certainty that your symptoms are not due to HIV/seroconversion, i.e. that something other than HIV is responsible for any symptoms you have now, or any that you may develop any time in the future (no matter how typical they might be for HIV).

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