Based on research trials that showed lower infection rates for people considered at high-risk for HIV, Truvada, a combination pill of emtricitabine/tenofovir disoproxil fumarate, was approved by the FDA on July 16, 2012, for Pre-Exposure Prophylaxis or PrEP. Since then, and especially in recent weeks, it’s been a news headliner.
PrEP is intended for people considered at substantial risk for HIV sero-conversion. It is not meant as a stand-alone drug. By this I mean that other methods for preventing HIV infection, such as safer sex practices, HIV testing, and counseling, should still be continued. It is not intended for people who need to prevent HIV after a single high-risk incident of possible exposure, such as a condom break or sexual assault. For that there is PEP, or Post-Exposure Prophylaxis, which is a 28-day course of therapy that should start within 3 days of the incident, and optimally even sooner.
Studies have shown that PrEP is 90–96% effective, but only if it is taken at least four times per week. A significant number of people—up to 52%—in these studies did not take it as prescribed. For those taking it less frequently, sero-conversion occurred about half of the time, depending on whether the exposure was within a day of PrEP or four days later.
PrEP is not a ‘morning after pill’ solution. You cannot pick and choose which days to take it depending on sexual encounters. Taking it less often can lead to the development of resistant HIV if sero-conversion occurs.
It is also important to be tested before beginning PrEP, and if you stop taking it, to get retested.
PrEP is clearly not for everyone. It is a commitment to taking a daily medication, side effects can occur, and it is expensive. (Editor’s Note: Supervisor and SF Bay Times columnist David Campos introduced legislation a few weeks ago that could provide subsidies to San Franciscans who would not otherwise be able to afford the drug.) Even with insurance coverage, there may be costly co-payments and the cost per year is at least $13,000.
Whether or not you should use PrEP is a personal decision based on your lifestyle and partner(s). Reading through the online blogs of PrEP users, it can be a substantial relief for people worried about their personal risk for HIV, such as sex workers or those with partners with detectable HIV viral loads. There does not appear to be an increase in risky sex behavior in men using PrEP, despite the fears that there would be an epidemic of so-called “Truvada whores.”
Since adherence to the drug in studies was variable, there is still ongoing research into PrEP’s effectiveness to help determine which approach works best for using the drug. New agents, such as Maraviroc, are being tested. A rectal gel, MTN-017, is also undergoing testing. Several other pharmaceuticals are in development through the HIV Prevention Trials Network, including a long-acting injectable drug.
Before the introduction of PrEP, approximately 50,000 new HIV infections were reported yearly in the United States. Between 2011 and 2013, only 1774 prescriptions for PrEP were documented. These figures do not, however, take into account all pharmacies and people receiving Truvada through ongoing studies. Therefore, it is still too soon to see if PrEP will have an appreciable impact on the epidemiology of HIV infection rates.
Below are just four of the many resources available for those who are interested in learning more about PrEP:
• San Francisco City Clinic- The clinic provides testing associated with PrEP and can provide you with 2 days worth of pills to get you started until you can see your primary care provider to obtain a prescription. 415-487-5538, http://www.sfcityclinic.org/
• UCSF OPTIONS Project- If you think you have been exposed to HIV, call OPTIONS to receive the latest advice, testing and PEP drug therapy. 415-502-8100, http://labs.ucsf.edu/options/where.html
• See http://joinprep.org/studies-enrolling-now for currently enrolling PrEP studies that you may be eligible for.
• Finally, for answers to many questions about PrEP, I recommend checking out this Q&A page online: http://men.prepfacts.org/the-questions/
Dr. Naomi Jay is a nurse practitioner in the department of Infectious Disease at UCSF.
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