Asking on behalf of a friend whose first language is not English. Then a small question regarding both of us.

We are both MSM, me with a female partner. Because of this both my friend and I test regularly and are 100% confident there are no previous risks or stis.

My friend engaged in protected anal insertive with an stranger and unprotected oral sex (he was insertive). Parter claimed to be neg, but after sex he disclosed he is hiv positive and in treatment. My friend panicked and started PEP 24 hrs later, on Bykrarvy 1 daily for a month, this happened 2 weeks ago. 

He could then confirm by going to sti clinic with partner during his regular follow up that partner has been treated for 3years and had "low viral count" (my friend chatted with physhologist in clinic and told him partner was "undetectable" but also a number he can't recall).

What's his risk for hiv?

Is Byctarviv effective as PEP? 

We read Truvada is the only approved one.

How can partner be "undetectable" but friend also heard a viral ct number? Is this more risky?

Friend tested neg Syphilis, Heps and HIV during PEP consultation.

Finally, I know my friend is okay, so I engaged today with him in masturbation, I only touched his scrotum (no contact with glans or precum/semen) and kissed his neck and nipples. He did not masturbated me. Is it safe for me to keep unprotected sex with my female partner ?

As you apparently know, when anti-HIV treatment reduces virus in the blood to undetectable levels, there is no risk of sexually infecting others -- as embodied in the common shorthand U=U:  undetectable equals untransmittable. Your friend's partner's HIV apparently is in excellent control, and he was under no obligation to inform your friend about his HIV status or to necessarily use condoms. (Of course it would have been courteous and most partners would expect to be informed -- but from an infection prevention standpoint, it wasn't necessary.) Although "undetectable" technically allows for a small amount of virus to be present, the research documenting the effectiveness of PEP showed zero infections in people exposed sexually to partners with such low virus levels. My guess is that the "number" in his viral load test was simply a statement of the sensitivity of the test.

That only one product (Truvada) is FDA approved for PEP only means it's the only one that has been studied formally. Almost certainly virtually all effective antiretroviral drugs, including Biktarvy, are effective.

Your partner could consider stopping PEP, which probably wasn't necessary -- but only with the approval of the clinic or doctor who prescribed it. But at this point, having taken it for two weeks, probably it is reasonable for him to continue the four week course even if unnecessary. Either way, the contact you had with him was entirely free of HIV risk and you can safely continue sex with your female partner.

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

HHH, MD

I have a few more follow up questions or assumptions to validate.

My friend refers bad headache on right temple at day 2 of PEP and has been having diarrhea up to today. With cramps 30m after eating. Also some muscle pain. Are these all normal Per AEs?

Also, yes, we are aware U=U, but since psychologist was not clear or friend didn't grab it we were not 100% sure on it. Will someone treated for 3years be most likely undetectable?

Is it safe to say that this 3rd person being on treatment, protected anal, and oral all make initial infecfion even without pep unlikely.

I also know mutual masturbation is safe for HIV. I have also heard though that 2 weeks after exposure hiv levels peak and infectivity increases. Is anyone on PEP (even if it ends up failing) as infectious as someone not on pep on this time frame? So I could add this as yet another reassurance from my contact with him?

Finally, when would you recommend testing after PEP? What type of tests? For ag/ab is rapid POC good, or do you recommend la blood drawn?

Undetection of virus certainly can and often does remain effective for many years. If he's been on the same drug(s) the whole time, it probably means it has been effective; otherwise his doctors would have changed to a different regimen.

Yes. Even if the other guy had not been on treatment at all, the likelihood of infection from any such exposure is no higher than 1% (one chance in a hundred), probably lower. It is safe to say that even without PEP, your friend/partner would not have been infected.

Too speculative. The risk is near zero and this detail probably makes no additional difference.

Different experts have different recommendations about HIV testing frequency and timing following PEP. After the last dose, I favor ~1 week, 4 weeks, and 6 weeks. But he should follow his doctor/clinic's advice. They probably are more experienced in this than I am. And I always adise lab-based AgAb testing rather than POC tests. The latter are good, but lab based tests are best.

We will not try to worry, will finish PEP and ask clinic on symptoms. We read diahrreha and headache is common, can I just ask what makes you think it may be caused by something else ?

It is reassuring to know undetectable viral levels can be reached relatively soon and keep like that with treatment. We were under the impression it could take years, but reading more on this let us know otherwise.

 This should take care of questions such as "was he low viral load or undetectable?", I understand the goal for ART is to get to undetectable, so doctors will keep or change meds to get there.

On my end, is it still safe to engage in mutual masturbation (should I be hypervigilant of not having any contact with any fluid as we did last time) with him while on PEP? Should I also take it?

I was getting scared and thinking on doing a PCR by 10-11 days next Friday, but I think I am overreacting ?

Yes it's still safe to have any sexual practice that provides you and either of your partners mutual pleasure. I would not advise PCR.

Perhaps it will also help you to know that in the 20 years of this and our preceding forum, with over 20,000 questions from people worried about having been exposed to HIV, not one has yet informed us they tested positive. You will not be the first. If it ever finally happens, it will not be from a near zero risk event of the sort you describe.

That concludes this thread. Do your best to believe the science and move on!