Research suggests that Truvada, a pre-exposure prophylaxis (PrEP) drug, is 99 percent effective against HIV transmission. A new case of HIV has underlined the fact that the drug is not a 100 percent guarantee. The first case of HIV contraction while taking PrEP has been presented at the 2016 Conference on Retroviruses and Opportunistic Infections this week in Boston.
The 43-year-old gay man adhered to a PrEP regimen for 2 years, yet tested positive for HIV recently. The man contracted a rare strain of the virus that was resistant to both of the main components of Truvada, tenofovir and emtricitabine.
Researchers say that HIV strains that are resistant to multiple drugs are very rare, and that other PrEP users should not panic. During clinical trials of Truvada that involved over 9,200 people such a virus was never seen.
Dr. Richard Harrigan, one of the researchers on the study said, “I certainly don’t think this is a situation which calls for panic. It is an example that PrEP can sometimes be ineffective in the face of drug resistant virus, in the same way that treatment itself can sometimes be ineffective in the face of drug resistant virus. Harrigan went on to say that the case shows that, although PrEP is beneficial, it is not an “infallible magic bullet.”
Tests indicate that the man contracted the HIV virus from a single individual. He has been on a successful HIV treatment program since his diagnosis and has a fully suppressed viral load.