PrEP presents questions for HIV prevention researchers, survey seeks answers

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The trial to determine the effectiveness of a vaccine against HIV that was known as HVTN 505 was underway in 2010 when results from another, wholly unrelated trial presented a challenge. Those results, from the iPrEx trial, showed that an antiretroviral drug taken as pre-exposure prophylaxis — or PrEP — was effective in protecting uninfected people from becoming infected with HIV.

Researchers had three choices, as they saw it — after letting participants know of this new, and promising prevention measure, they could leave it at that. Or they could also refer participants to PrEP providers. Finally, and this is the option researchers chose, they could  include providing PrEP as part of the trial, for participants who were interested.

As it happened just 1 percent of participants in the placebo arm, and only 1 percent of those testing the actual vaccine candidate took them up on it. And as it happened, the vaccine candidate itself was ineffective.

The trial however set precedent in one regard — it was the first to confront the ethics of how to test a potentially effective biomedical prevention tool, when another that has been proven effective and can be easily provided and monitored already exists. Still the questions researchers asked, and answered continue, while new ones arise in different settings.

In any trial of an HIV prevention measure, ethics demand that all known effective measures, which in earlier years added up to counseling and condoms, be made available. In a setting where PrEP would not otherwise be available though, is offering it sweetening the pot more than is ethically acceptable?

With the answers to those questions diverging, depending on who you ask — that is with UNAIDS presenting  differing  “considerations,” and “guidelines”, and the HIV Prevention Trials Network weighing in with additional thoughts, the Treatment Action Group surveyed community members and assembled the answers here. The answers, particularly in the face of continuing unknowns, including the impact of PrEP on vaccine induced immune responses, don’t cover every occasion. But with recommendations that include all biomedical prevention trials provide information on the numbers of participants linked to PrEP, and that community input on PrEP be routine, the report, compiled with support from the Netherlands-based Aidsfonds, lays out how PrEP has changed not only HIV prevention, but the quests for new answers.

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