A study from Kaiser Permanente San Francisco Medical Center that examined the efficacy of preexposure prophylaxis, or PrEP, to prevent HIV infections found zero new HIV infections among patients during more than two and a half years of observation.
Jonathan Volk, MD, a physician and an epidemiologist at Kaiser Permanente San Francisco Medical Center, was the lead author of the study published in the journal Clinical Infectious Diseases.
During the 32-month observation period of the study, more than 1,000 patients received referrals for PrEP and more than 650 people began the PrEP protocol, which consisted of receiving a daily regimen of a blue pill called Truvada.
On average, patients used PrEP for 7.2 months, providing researchers with 388 person-years of observation of PrEP use. After two and a half years of observation, 100 percent of the participants on the PrEP protocol remained free of HIV.
University of California-San Francisco researchers Kimberly A. Koester and Robert M. Grant, MD, told The Washington Post that the outcome of the Kaiser Permanete study is "tremendously good news."
Although no new cases of HIV were recorded during the study, 30 percent of PrEP users had been diagnosed with at least one sexually transmitted infection six months into the study.
"Without a control group, we don't know if these STI rates were higher than what we would have seen without PrEP," noted co-author Julia Marcus, PhD. "Ongoing screening and treatments for STIs, including hepatitis C, are an essential component of a PrEP treatment program."