These documents speak to the use of PrEP:
Centre for Disease Control (CDC). (2009). CDC trials of pre-exposure prophylaxis for HIV prevention. Retrieved July 10, 2009 from, http://www.prepwatch.org/pdf/Trials/CDC_trials_April.2007.pdf.
Centre for Disease Control (CDC). (2009). CDC trials of pre-exposure prophylaxis for HIV prevention. Retrieved July 10, 2009 from, http://www.cdc.gov/hiv/resources/Factsheets/PDF/prep.pdf.
Okwunda, C. I., & Okoromah, C. A. N. (2009). Antiretroviral pre-exposure prophylaxis (PrEP) for preventing HIV in high-risk individuals. The Cochrane Collection 2009 (2). Retrieved July 10, 2009, from http://www.cochrane.org/reviews/en/ab007189.html.
Willyard, C. (2009). A preemptive strike against HIV. Nature Medicine 15(2), 126-129.