PrEP Uptake of 25% Enough to Prevent 30% of HIV Infections in MSM

The results of a new study from investigators at Drexel University revealed that if 25% of high-risk men who have sex with men (MSM) appropriately used the pre-exposure prophylaxis (PrEP) Truvada, 3 out of every 10 HIV infections in this population could be prevented.

For the study, the investigators used a cohort “that would reflect a true-to-life 10,000-person population among urban, nonmonogamous MSM who were defined by the Center for Disease Control and Prevention (CDC) as ‘high-risk’ [for HIV infection]. All the numbers were derived from the CDC’s study of 21 US cities,” according to Drexel’s official press release on the study.

The HIV status of the cohort was assigned in the model as follows:

• A total of 19% were HIV-positive 44% were unaware of their HIV status
• A total of 81% were HIV-negative 36% had not been tested in 1 year

The investigators found that when 1% of the HIV-negative population used PrEP, 1.6% of HIV infections were prevented; however, when 25% of the HIV-negative population used PrEP, a whopping 30.7% of HIV infected were prevented.

In addition, the investigators looked at the potential outcomes of using other prevention methods, such as condoms, using different positions during intercourse (seroadaptive behaviors), and treatment as prevention. The results for these methods were indicated in the press release as follows:

• Condom use prevented 48.8% of infections;
• Seroadaptive behaviors prevented 37.7%; and
• Treatment as prevention prevented 27.1%.

Combining these efforts yielded even better results, preventing 72.2% of infections.

The high prevention rate of PrEP makes it a powerful tool to use in combination with these other efforts. Michael T LeVasseur, PhD, MPH, a biostatistician at the Center for Health Incentives and Behavioral Economics at Drexel remarked on this in the press release, stating, “PrEP is just another ‘tool in the toolbox’ for HIV prevention, but it is an important one. PrEP can empower individuals who are in relationships where 1 person has HIV and the other doesn’t. It can also ease anxieties around HIV testing, as well as enhance sexual intimacy.”

The results of this study add more evidence to the success of PrEP in preventing HIV infections; however, PrEP uptake around the world, particularly in individuals at highest risk, remains low.

According to an article published in the November 2017 issue of Contagion®, “pharmacy fulfillment data from January 2012 through September 2016 [indicated that] women made up almost half (42%) of all individuals prescribed PrEP for HIV prevention. Since 2014, the proportion of women has decreased dramatically, currently accounting for only 15% of all recipients. In addition, young adults represent a disproportionately small number of PrEP users relative to their importance as a key risk group; just 11% of men and 24% of women prescribed PrEP were under age 25. Although only 40% of prescriptions had associated race and ethnicity information, the trends seem likely to reflect fundamental inequities in health care access across the United States. In 2015, blacks and Hispanics/Latinos accounted for 45% and 24% of all new HIV diagnoses in the United States, respectively, yet they comprised less than a quarter of all PrEP recipients (13% Hispanic/Latino, 10% black) across the 4 years of available data.”

The Drexel investigators feel that their research can help increase PrEP uptake by highlighting its effectiveness, particularly in combination with other techniques. “Many men who have sex with men have felt significant anxiety around sexual intimacy due to fear of HIV infection, even with condom use, frequent HIV testing and seroadaptive techniques,” according to Dr. LeVasseur. “Highlighting how effective these prevention methods are would certainly lead to an increase in PrEP uptake and easing of the mind.”