[Question #7575] HIV RISK AND PEP

1 months ago
Hello! 
So, I have a few questions. Recently I've had casual sex with another male(I'm MSM). I don't know him very much. The question is the sex started with a condom but he took it off and I didn't notice it... stealthing. I was anal receptive and he was anal active. He ejaculated inside.  Soon after I realized what happened I sook health care and took some medications for preventing STI's(gonorrohea, chlamydia, syphilis). Started PEP for HIV 5 hours after the meeting. So, I have some questions, as I've been dealing a lot with anxiety these days and I hope you doctors could help me.
1)What are the odds that I'll get HIV starting PEP 5 hours after the exposition? Considering him as an HIV-positive source and considering I'm taking it the 28 days and at the right time of the day.
2) The test at 1 month after exposure would be reliable? if not, when could I easy my mind being certain I did not contract HIV?
3) Could I take coronavac vaccine while on pep? Would it make higher the chances I would get HIV or not be immunizated?
Thanks!
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
1 months ago
Welcome back to the forum.

Sorry to hear about your condom failure. Your questions are very reasonable. However, I'll also point out that you may have a lot quicker and easier exit path out of your anxiety:  ask your partner to be tested. Even better, suggest that the two of you be tested for HIV (and pehaps other STDs as well); maybe you would find he is just as concerned about this event as you are. If he has a negative HIV at this time, you'll know you were not possibly exposed and could stop PEP. And as just implied, perhaps he will appreciate the same reassurince.

Also remember that even if he had HIV (and is not on treatment), the risk of infection for the bottom partner from a single episode of unprotected anal sex is around 1%, i.e. 1 chance in a hundred. That's plenty high to justify PEP, but still the odds are strongly in your favor, even without PEP.

To your questions:

1) Assuming your partner doesn't get tested, it was entirely approporiate to seek PEP. The exact success rate of PEP isn't known, but in gneral it's believed to be at least 90% effective.And when started at 5 hours, probably close to 100%.

2) Testing is not valid while taking or immediately after finishing PEP. The window period clock starts after you finish treatment. You can have fairly reliable AgAb (4th generation) testing 2-3 weeks after the last dose, but not conclusive until 6 weeks afterward -- and some experts believe it can take even longer and reommend final testing 3 months after finishing treatment. (This is one important downside of PEP often forgotten by both exposed peraons and the prescribing doctors:  it prolongs the time of potential anxiety until conclusive testing.)

3) No drugs are known to affect the reliability of COVID vaccine (or any other vaccine); that includes anti-HIV drugs. And there is no risk the other way either -- i.e. no reason to be concerend about the COVID vaccine interfering with HIV drugs or making PEP less effective. If you have access COVID immunization, for sure you should do it:  at this point in time, you're at far higher risk of serious illness or death from coronavirus than from HIV.

One final comment:  It's good you're paying attention to sexual safety -- congratulations for using a condom. Unoftunately that it failed, but your intent was good and I urge you to keep it up. However, aapparently you didn't follow another equally important aspect of safe sex between men:  it can be summarized as "do ask, do tell". Never, ever have sex -- especially if high risk, i.e. anal sex -- without first discussing HIV status with your partner, and avoid sex (or at least anal sex) with those who are positive and not on effective treatment, don't know, or seem evasive about it. Think how much less worried you would be if you were more certain he wasn't infected. Something to keep in mind for the future.

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

HHH, MD
---
1 months ago
Thanks for the answers. No way I could contact him. 
So I could be less worried as the odds are really low considering the risk in this situation, even If he was hiv positive?
And one more thing, yesterday i took the pep 4 hours after the stablished hour for me, should i be concerned?
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
1 months ago
Yes, you correctly understand:  the odds you were infected indeed are extremely low, even if your parter is infected.

Timing of PEP doses doesn't need to be that precise. Take it once daily, but it doesn't need to be exactly at 24 hour intervals. You have several hours flexibility each day. That said, most people who need to take medication regularly do better at remembering if they set a schedule and stick with it.
---
19 days ago
Thanks for the answer. One last thing, is there some evidence on interactions between weed and PEP?Like lowering the efficacy?the PEP i'm using is tenofovir, lamivudine and dolutegravir. Thanks.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
19 days ago
I am unaware of interactions of marijuana or any other substance with PEP effectiveness or drug toxicity. 

Thanks again for using the forum. Take care and stay safe.
---