In the first case of its kind, a man has contracted HIV even while taking the HIV-prevention drug Truvada, according to doctors from the Maple Leaf Medical Clinic in Toronto. The research was presented at the 2016 Conference on Retroviruses and Opportunistic Infections (CROI) in Boston.
Truvada is marketed as more than 90 percent effective at preventing HIV infection if taken daily; studies suggest that the true effectiveness is higher than 99 percent, even when taken only four times a week.
The drug failed, not because it was intrinsically defective, but because the man in question was exposed to a new, multi-drug-resistant form of HIV.
"It is an example that demonstrates that PrEP [Pre-Exposure Prophylaxis ... ] 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," researcher Richard Harrigan said.
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| Man contracts HIV while on HIV protection drug that's supposed to be over 90 percent effective |
The infection occurred in a 43-year-old man who had been taking Truvada for 24 months. The timing of his contracting HIV could be pinpointed with a high degree of accuracy, because he tested positive for p24 antigen (which appears three weeks after HIV infection but vanishes within a few weeks), but negative for HIV antibodies (which appear within two to eight weeks).
Pharmacy records showed that he had always refilled his prescription on schedule, while blood tests taken after his positive HIV tests confirmed adequate adherence to the drug regimen over the prior one to two months, the time period in which he had become infected.
"This person claims he was taking PrEP every day and I believe him," said Robert M. Grant, of the University of California-San Francisco, who led the first study to show PrEP's effectiveness in men who have sex with men (MSM), and transgender women.
One of the major takeaways of the case, researchers suggest, is that there is no such thing as a 100 percent guarantee.
"After 32 years of experience with HIV research, I have learned never to say 'never'," Grant said.
Are HIV superbugs on the horizon?
The most disturbing implications of the case may not be about the effectiveness of Truvada per se, but the future of the HIV virus and AIDS. That's because this is also thefirst known case of multi-drug-resistant HIV.
Truvada consists of a cocktail of two drugs that are also used to treat HIV: tenofovir and emtricitabine. Tenofovir is the most widely used anti-retroviral drug in the world, and as a consequence, the prevalence of tenofovir-resistant HIV is increasing. Emtricitabine resistance, however, is less common, and infection with multi-drug-resistant HIV was previously unknown.
"I think we would assume that the efficacy of PrEP would be lower if there is exposure to virus which is resistant to either drug, and lowered further if there is exposure to virus resistant to both drugs," Harrigan said.
The man in question is now undergoing treatment with other anti-HIV drugs, and has a fully suppressed viral load. But his case raises the frightening specter of HIV "superbugs," evolved to resist most or all of the most effective anti-retroviral drugs. Antibiotic-resistant superbugs are already a major global health problem, and multi-drug-resistant malaria is also rearing its head.
The problem is that, unlike with antibiotics – which are grossly over-prescribed, are used to promote growth in healthy livestock, and have many natural alternatives – there are no simple changes to prescribing practices that could slow the evolution of drug-resistant HIV.
What will the implication be for global health if we return to the days when HIV was nearly impossible to treat?
Sources for this article include: TheVerge.com | DataLounge.com | LGBTQNation.com | NaturalNews.com | NaturalNews.com | Science.NaturalNews.com
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