Evidence has been mounting for years that a prevention option known as pre-exposure prophylaxis (PrEP) can provide effective protection against the human immunodeficiency virus (HIV). This year, a significant study published in September 2015 in Clinical Infectious Diseases found no new HIV infections among 657 PrEP users who were observed over a two-and-a-half-year period.
“Our study is the first to extend the understanding of the use of PrEP in a real-world setting and suggests that the treatment may prevent new HIV infections even in a high-risk setting,” says lead author Jonathan Volk, MD, MPH, an infectious disease specialist at Kaiser Permanente San Francisco Medical Center.
In 2012, the Food and Drug Administration (FDA) approved the daily use of the PrEP drug Truvada, in combination with safe sex practices, to reduce HIV risk in uninfected adults. Truvada combines the antiviral drugs emtricitabine and tenofovir in a single pill. Then-FDA commissioner Margaret Hamburg, MD, called the drug’s approval “an important milestone in our fight against HIV.”
A new study published online by the New England Journal of Medicine suggests that Truvada may also be effective if taken as needed, rather than daily. Study participants were instructed to take two pills before and after having sex. The results showed an 86 percent reduction in infection rate.
PrEP users may experience side effects such as nausea, abdominal pain, diarrhea, headache, and weight loss. While these symptoms are usually mild, persistent or worsening side effects should be reported to a doctor.
PrEP is not intended for patients already exposed to HIV. Post-exposure prophylaxis (PEP) treatment involves antiretroviral drugs, but these medicines must be taken within 72 hours of exposure and are not always effective.
Despite progress in treatment and prevention, HIV remains a serious health concern. The U.S. Centers for Disease Control and Prevention (CDC) estimates that 50,000 people in the United States become infected with HIV each year.