The Power of PrEP


The results of a new study demonstrate that PrEP can reduce new infections within a population even when the risk of HIV remains high and other proven treatment and prevention strategies are optimized.

Since 2012, a combination tablet containing tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) has been approved by the Food and Drug Administration and available in the United States for the prevention of HIV infection as pre-exposure prophylaxis (PrEP).1 Several large investigations have demonstrated the considerable efficacy of TDF/FTC taken daily or intermittently, reducing the risk of HIV acquisition by more than 95% in high-risk individuals. Estimates of how PrEP, if routinely accessible, could affect the overall incidence of HIV infection suggest significant reductions are possible on a population level, but real-world data until recently, have remained elusive.2

The Expanded PrEP Implementation in Communities of New South Wales (EPIC-NSW) study, recently published in the Lancet HIV, provides real-world data confirming that PrEP is an effective tool for reducing new HIV infections in a high-risk community.3 Investigators recruited 3700 gay and bisexual men at high risk of HIV infection in New South Wales, Australia, initiated them on daily TDF/FTC between March 1, 2016, and October 31, 2016. In the year following enrollment, there was a 25.1% relative risk reduction in the incidence of HIV infection among gay and bisexual men in New South Wales compared with the year prior to recruitment. Importantly, this reduction occurred during a period when the risk of HIV infection in the community remained high.

During the study period, there were noted increases in reported condomless anal intercourse among gay men in the community as well as more cases of chlamydia and gonorrhea infections.4 The reduction in HIV also occurred at a time when the UNAIDS 90-90-90 targets had already been achieved in New South Wales.5 In other words, at least 90% of individuals with HIV in the community were diagnosed, on treatment, and virally suppressed. As a result, this study demonstrates that PrEP can reduce new infections within a population even when the risk of HIV remains high and other proven treatment and prevention strategies are optimized.

To realize similar benefits in other communities, routine access to PrEP for all high-risk individuals is essential. Unfortunately, access to PrEP in many areas of the world has been slow and disparate. In the United States, less than 10% of the estimated 1.1 million individuals at risk of HIV infection are receiving PrEP.6 The gap between the numbers of persons with an indication for PrEP and those prescribed PrEP has been more substantial among women and those from certain racial or ethnic backgrounds.

Barriers to PrEP are common. They range from a lack of knowledge or perceived risk by the patient or their provider, substance abuse, poor mental health, discrimination, and poverty.7 For many, cost may be the most substantial barrier to obtaining and maintaining PrEP medications. To improve access to all persons in Australia, TDF/FTC was added to the Pharmaceutical Benefits Scheme, which subsidized the cost of PrEP for most individuals. Thereafter a concerted and coordinated effort by government officials, public health services, medical providers, and advocacy groups rapidly expanded the role of PrEP in New South Wales.8 Their efforts led to a rapid uptake of PrEP in the community, a corresponding decline in new HIV infections, and should serve as an example for communities around the world.

Dr. Schafer is the Contagion® section editor for HIV and an active member of the Society of Infectious Diseases Pharmacists (SIDP).


  1. Centers for Disease Control and Prevention: US Public Health Service: Preexposure prophylaxis for the prevention of HIV infection in the United States—2017 Update: a clinical practice guideline. Published March 2018. Accessed October 25, 2018.
  2. Kasaie P, Pennington J, Shah MS, et al. The impact of pre-exposure prophylaxis among men who have sex with men: an individual-based model. J Acquir Immune Defic Syndr. 2017(2):75:175-183. doi: 10.1097/QAI.0000000000001354.
  3. Grulich AE, Guy R, Amin J, et al. Population-level effectiveness of rapid, targeted, high-coverage roll-out of HIV pre-exposure prophylaxis in men who have sex with men: the EPIC-NSW prospective cohort study. Lancet HIV. 2018;pii: S2352-3018(18)30215-7. doi: 10.1016/S2352-3018(18)30215-7.
  4. Holt M, Lea T, Mao L, et al. Community-level changes in condom use and uptake of HIV pre-exposure prophylaxis by gay and bisexual men in Melbourne and Sydney, Australia: results of repeated, behavioural surveillance 2013-17 [Correction appears in Lancet HIV. 2018;5(8):e411. doi: 10.1016/S2352-3018(18)30186-3]. Lancet HIV. 2018;5(8):e448-e456. doi: 10.1016/S2352-3018(18)30072-9.
  5. Keen P, Gray RT, Telfer B, et al; for the NSW HIV Prevention Partnership Project. The 2016 HIV diagnosis and care cascade in New South Wales, Australia: meeting the UNAIDS 90-90-90 targets. J Int AIDS Soc. 2018;21(4): e25109. doi: 10.1002/jia2.25109.
  6. Huang YA, Zhu W, Smith DK, Harris N, Hoover KW. HIV Preexposure Prophylaxis, by Race and Ethnicity — United States, 2014-2016. MMWR Morb Mortal Wkly Rep. 2018;67(41):1147-1150. doi: 10.15585/mmwr.mm6741a3.
  7. Marks SJ, Merchant RC, Clark MA, et al. Potential healthcare insurance and provider barriers to pre-exposure prophylaxis utilization among young men who have sex with men. AIDS Patient Care STDS. 2017;31(11):470-478. doi: 10.1089/apc.2017.0171.
  8. New South Wales Ministry of Health. NSW HIV strategy 2016—2020. 2015. Accessed August 2, 2018.
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