Dear Dr. Bob,

Just now I read your appraisal of the Swiss report on having unprotected sex when one's VL is undetectable.

Yup, I'm poz and undetectable for over 5 years. I believed the report, and just today received unprotected anal sex - not once, but twice from my Hiv neg partner.

There seems to be no doubt that he must begin PEP within 24 hours (with Atripla or the equivalent?), unless you advise otherwise.

What makes matters worse is I have followed every rule for over 18 years.

Kindly reply.

signed, a dumb guy with Swiss roots

Hi Swiss-Roots Guy,

Based on what we know or perhaps more accurately what we don't know I would recommend a course of PEP for your partner. Perhaps your HIV specialist would be willing to prescribe the medications on an urgent basis and follow your partner for his 28-day course as well as arrange for his post-PEP follow-up tests. An HIV specialist can help select the best PEP regimen based on your medication history and resistance profile.

The reassuring news from the Swiss Report and other sources is that since your viral load has been undetectable, the HIV-transmission risk would be significantly decreased.

Good luck to you both. I'm here if you need me, OK?

Dr. Bob