In very rare cases, some people who adhere strictly to their PrEP (pre-exposure prophylaxis) therapy may still get infected with HIV. This is because there’s evidence of a rare virus resistant to antiretroviral drugs such as Truvada.
This conclusion was reached at after a PrEP user from New York City was reported to have become HIV positive with the PrEP medication resistant virus. This is the second case of such infection to be reported. The case was reported at this year’s HIV Research for Prevention conference dubbed HIVR4P 2016. The conference was held in Chicago in November this year. With only two such cases reported, scientists believe that this is a rare incident but not an impossibility.
HIV Virus with Multiple Resistance Mutations
Dr. Howard Grossman, from the Cleveland Clinic Florida, told the conference that the man, in his early 20s, is said to have acquired the virus from a casual male partner with a virus that has multiple resistance mutations. Some of the mutations seem to be resistant to some components of Truvada including emtricitabine and tenofovir disoproxil fumarate.
The patient is said to have engaged in unprotected sex while he was taking PrEP. The gay man had gone for HIV testing several times and received negative results each time. This was before he was put on PrEP on January 1st, 2016. He later had unprotected sex with the casual partner and in early May conventional viral load tests were conducted. The RNA tests showed an undetectable viral load. Dr. Grossman said that this is quite unusual during early HIV infection making the tests more hard to interpret.
Dried blood spots and hair samples were tested in June. The tests showed that the man had adhered to the prescribed Truvada therapy in April and May. The tests also showed that his viral strains and those of his HIV-positive partner were not related. Doctors made the conclusion that this wasn’t a case of PrEP failure because he had not had any lapses in adherence but, a case of the virus, from the casual partner, having multiple mutations.
When resistance tests were done they revealed that the patient’s virus was resistant to many of the Nucleoside Reverse Transcriptase Inhibitors. NRTIs are the backbone of HIV treatment. Due to the high mutation, the man was given an intensive drug regimen, in addition to the existing Truvada. He’s currently said to be doing well with this new regime and has managed to maintain an undetectable viral load.
Two Similar Cases so Far
Dr. Grossman said this case was similar to the first case reported on PrEP failure, identified earlier this year. The case is also said to have involved the acquisition of a virus strain resistant to multiple drugs.
He, however, insisted that these two cases are not an indication of PrEP failure. He added that this proved that Truvada PrEP does not offer any protection against viruses resistant to its component drugs. However, he added that such viruses are extremely rare noting that only two reports have been made so far in a case where 100,000 people are taking PrEP indicating an extremely low failure rate.
Dr. Grossman noted that the man was in the habit of taking the insertive role only when having sex with his casual partners. This, he added, is an indication of the myth among gay men that tops don’t get infected with HIV. This myth has clearly been debunked by this case.