The proportion of gay and bisexual men at risk for HIV who are using pre-exposure prophylaxis (PrEP) has risen more than fivefold in recent years, according to a study from the Centers for Disease Control and Prevention (CDC) presented at the Conference on Retroviruses and Opportunistic Infections (CROI) this month in Seattle.

However, while PrEP use has increased substantially among at-risk men who have sex with men (MSM) overall, it remains low among Black and Latino gay and bi men, who have disproportionately high rates of new infections, Teresa Finlayson, PhD, MPH, of the CDC, and colleagues reported.

Truvada (tenofovir disiproxil fumarate/emtricitabine) taken once daily or “on demand” before and after sex dramatically reduces the risk of acquiring HIV. Since its approval for HIV prevention in 2012, the CDC, Truvada manufacturer Gilead Sciences and others have attempted to estimate the total number of people using PrEP in the United States, but this has proved difficult because this information is not centrally collected.

At last year’s CROI, Dawn Smith, MD, MPH, of the CDC, reported that in 2015, a total of 1,145,000 U.S. residents were at substantial risk of acquiring HIV and good candidates for PrEP. Among gay and bi men—who account for a large majority of new HIV cases—about 814,000 were eligible, along with around 258,000 heterosexuals (two thirds of them women) and nearly 73,000 people who inject drugs. But just 8 percent of all eligible individuals were actually using PrEP (14 percent of whites, 3 percent of Latinos and 1 percent of Black people).

At this year’s meeting, Finlayson’s team reported findings from an analysis of changes in PrEP awareness and use among MSM between 2014 and 2017 using National HIV Behavioral Surveillance data.

The researchers interviewed more than 8,000 men in 20 cities across the country, recruiting them at bars and other venues popular with gay men. The participants were HIV negative and considered to be at substantial risk for HIV, meaning they had an HIV-positive male sex partner, two or more male partners, reported condomless anal sex or had a sexually transmitted infection (STI) within the past year.

Between 2014 and 2017, PrEP awareness increased from 60 percent to 90 percent, Finlayson reported. While PrEP awareness increased in all racial/ethnic groups, in 2017 it remained lower among Black and Latino men (86 percent and 87 percent, respectively) compared with white and “other” men, including Native Americans, Asians and Pacific Islanders (95 percent and 94 percent).

PrEP use also rose, from 6 percent in 2014 to 35 percent in 2017. Again, PrEP use was less common among Black men (26 percent) and Latino men (30 percent) compared with white men (42 percent) and “other” men (40 percent).

“Although HIV PrEP use increased by over 500 percent from 2014 to 2017, only one in three men at risk for HIV infection reported using PrEP,” the researchers concluded. They suggested that efforts to raise PrEP use among Black and Hispanic men could help reduce HIV disparities in the United States.

In a related study, Kevin Weiss, MPH, of Emory University in Atlanta, and colleagues estimated the proportion of MSM eligible for PrEP. In 2015, the CDC estimated that 25 percent of sexually active gay and bi men qualified for PrEP, they noted as background.

This analysis was based on a slightly different definition of risk, as used in the 2017 U.S. Public Health Service (USPHS) clinical practice guidelines: having had a male sex partner within the past six months, not being in a monogamous relationship with an HIV-negative partner or having had condomless anal sex or any bacterial STIs within the past six months.

Between July 2017 and January 2019, the researchers conducted a nationwide web-based study of 4,196 cisgender (non-transgender) men who had ever had sex with a man. Of these, 45 percent met the USPHS indications for PrEP. Among men who met the criteria, most did so because they had condomless anal sex.

In this analysis, white, Black, Latino and “other” men had a similar likelihood of being eligible for PrEP based on recent condomless sex or STIs (32, 32, 33 and 30 percent, respectively). Similar proportions were also eligible across geographic regions. Young men ages 15 to 17 were least likely to meet those criteria (14 percent) while those ages 45 to 54 were most likely (42 percent).

“More sexually active MSM are likely indicated for PrEP” and “[a] lower fraction of indicated men may be receiving PrEP” than previously estimated, the researchers concluded. “Given rising HIV case counts in younger and minority MSM, additional age- and race/ethnicity-based considerations for uptake may be needed to improve PrEP access.”

As part of the Trump administration’s recently announced Ending the HIV Epidemic plan—which aims to reduce new infections by 75 percent within five years and by 90 percent within 10 years—the CDC said it will expand efforts to increase PrEP awareness, access and use, particularly among those at highest risk for HIV infection.

Click here to read Finlayson’s study abstract.

Click here to read Weiss’s study abstract.

Click here to learn more about PrEP.