No decrease in HIV infections among gay men per CDC data; More PrEP coverage needed

by Emily Newman

January 4, 2017

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This month, the Centers for Disease Control and Prevention (CDC) released the Annual HIV Surveillance Report—a detailed report that serves as our primary source of who’s getting HIV in the U.S. year by year.

There were a few notable highlights from this year’s report. Overall, the number of HIV infections that happen every year in the U.S. is going down. In 2015, there were 39,513 new infections—a 19% decrease from 2005 to 2014.

But among men who have sex with men, the number of new HIV infections has remained surprisingly stable. In 2015, there were 26,376 HIV infections attributed to male-male sexual contact, compared with 26,338 in 2010. (The intervening years also saw about 26,000 HIV infections every year.) Since PrEP was approved in 2012, its uptake has been highest among men who have sex with men. What’s going on, and why doesn’t the number of HIV diagnoses among men who have sex with men seem to be declining as PrEP use is increasing?

“Stable and even increasing HIV infection incidence in some groups in the era of high treatment access in high-income settings shows that business as usual for HIV prevention is not enough to radically reduce new HIV infections.” 

–Jared Baeten, MD, PhD

First, this isn’t to say that PrEP isn’t preventing new infections or benefitting people who were or are on PrEP. In some places—such as San Francisco—the number of new infections is on the decline, and experts attribute this at least in part to PrEP. The San Francisco AIDS Foundation PrEP Health Clinic, which has enrolled more than 1,800 people into the program, has not seen any new HIV infections since the program began in 2014. During the same time frame, there have been over 85 new HIV infections among clients not on PrEP.

But country-wide, it seems like PrEP’s impact is much smaller than it could be.

The reason, according to compelling research published recently in the Journal of Infectious Diseases, is likely due to coverage. Far fewer people are taking PrEP now than need to be for PrEP to significantly reduce the percentage of new infections that happen every year.

Samuel M. Jenness, PhD and colleagues described a mathematical modeling study, which used sexual behavior data from men who have sex with men in the U.S. and PrEP adherence data from PrEP demonstration projects, to estimate how different factors will influence the number of HIV infections averted by PrEP over time.

The researchers found that the greatest contributor to PrEP’s future success was coverage—or how many people who may benefit from PrEP that are actually taking it.

The researchers found that, over 10 years, PrEP could prevent:

• 33% of new HIV infections if 40% of at-risk men who have sex with men (MSM) take PrEP
• 41% of new HIV infections if 60% of at-risk MSM take PrEP
• 50% of new HIV infections if 90% of at-risk MSM take PrEP

Comparatively, the researchers estimated that HIV infections among men who have sex with men will only decrease by about 10% with 10% of at-risk men taking PrEP.

(The model accounted for the fact that not everyone taking PrEP would be adherent—and made estimates assuming that about 60% of the sample would be highly adherent to the PrEP regimen.)

Jared Baeten, MD
(Photo: Liz Highleyman)

Simply put, “as more at-risk men receive PrEP, the impact of PrEP increases,” said Jared M. Baeten, MD, PhD, in an accompanying editorial commentary published in JID.

“The number of persons prescribed PrEP in most locales remains low from a coverage perspective, and thus, its impact to date on the HIV epidemic, in the United States and globally, is substantially smaller than it could be,” said Baeten.


It’s not known exactly how many people in the U.S. are taking PrEP, although the number likely falls far short of need. One study, presented in July of 2016, counted 60,872 men in the U.S. taking PrEP. This is far fewer than the estimated 492,000 men who have sex with men in the U.S. that the Centers for Disease Control and Prevention estimate have “substantial” HIV risk that would make them appropriate candidates for PrEP.

“Looking ahead, PrEP delivery is likely to evolve in the United States and globally, as experience and comfort are gained,” said Baeten. But to achieve the coverage needed to significantly change the course of the epidemic, he said, we must work to remove barriers to PrEP and make it more accessible to people that need it… Stable and even increasing HIV infection incidence in some groups in the era of high treatment access in high-income settings shows that business as usual for HIV prevention is not enough to radically reduce new HIV infections,” he said.

Pierre-Cédric Crouch,
PhD, ANP-BC

If you’re a healthcare provider for gay and queer men, are you telling them about PrEP? Read this editorial by Pierre-Cédric Crouch, PhD, ANP-BC, who is a PrEP provider and nursing director at Magnet for San Francisco AIDS Foundation.  


Sources

CDC. HIV Surveillance Report, 2015.


CDC. Vital Signs: Estimated Percentages and Numbers of Adults with Indications for Preexposure Prophylaxis to Prevent HIV Acquisition — United States, 2015, 2015.

Baeten, J. Making an Impact With Preexposure Prophylaxis for Prevention of HIV Infection, JID, 2016.

Jenness, S. and colleagues. Impact of the Centers for Disease Control’s HIV Preexposure Prophylaxis Guidelines for Men Who Have Sex With Men in the United States. JID, 2016.


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