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A 50-year-old Dutch man has become the third person worldwide to have contracted HIV despite taking the daily HIV-prevention regimen known as pre-exposure prophylaxis (PrEP). In the first two cases, both contracted a multi- strain of HIV that was resistant to tenofovir and emtricitabine, the two active medications used in Truvada, a common form of PrEP. But in this third case, the man had not contracted this drug-resistant strain.
So what happened?
According to poz.com, the man in question kept incredibly detailed notes about his sex life on his phone. During his eight months on PrEP, the man had 200 instances of condomless receptive anal sex with roughly 152 partners.
Doctors have a theory about how he could have contracted HIV while on PrEP:
“[Doctors] theorized that it is possible that the man was repeatedly exposed to HIV, which, kept relatively in check by Truvada, remained in a localized infection in his rectum for a time without spreading throughout the body. Then perhaps a drop in Truvada concentration in the rectum, maybe occurring without a corresponding drop in blood levels, allowed a window for HIV to thrive and establish an infection throughout the body.”
The man also participated in chemsex, using drugs such as “crystal meth, cocaine, GHB, mephedrone and ketamine” and sometimes having five or more sex partners a day.
The man was taken off of Truvada in fear that he might develop a resistance to its tenofovir and emtricitabine ingredients. He was subsequently given combination antiretroviral therapy. As of today, he is HIV-positive with an undetectable viral load.
Researchers estimate that, when taken daily, PrEP reduces the possibility of HIV-transmission by 99%. This man may have fallen through that one percent.
Despite this individual case, tens of thousands of people around the world currently take PrEP and continue to benefit from the drug’s high efficacy rate.