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March 05, 2024
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PrEP use up, HIV incidence down, data show

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Key takeaways:

  • PrEP coverage in the U.S. between 2012-2021 ranged from 3.8% in West Virginia to 22.2% in New York.
  • Australian data showed that taking PrEP more than 60% of the time reduced HIV incidence by 79%.

DENVER — Data from the United States and Australia show that PrEP uptake and adherence has increased, and the incidence of HIV has declined in recent years, researchers reported.

“Our prior analysis examined the ecological associations of PrEP uptake and trends in new HIV diagnoses in U.S. states through 2017 and found a significant dose-response relationship between state-level PrEP prescriptions and new HIV diagnoses,” Patrick Sullivan, DVM, MD, professor of epidemiology at Emory University, told Healio. “As PrEP use has increased since that time, we aimed to understand further the impact of PrEP use and HIV viral suppression on reducing new infections.”

IDN0324Sullivan_Graphic_01_WEB

Population-level protection

Sullivan and colleagues studied publicly available data on PrEP prescriptions and calculated PrEP coverage per 100 people with indications in each state during each year. They then calculated quintiles of mean PrEP coverage during 2012-2021 for each U.S. state and the District of Columbia. For each quintile, they calculated the estimated annual percent change (EAPC) in HIV diagnosis rates using modeling and adjusted the estimates for prior year state-level viral suppression.

Sullivan presented the findings at the Conference on Retroviruses and Opportunistic Infections (CROI).

Overall, the study showed that the estimated state-specific EAPC in HIV diagnosis rates between 2012 and 2021 ranged from –11.9% (95% CI, –13% to –10.8%) in Washington, D.C., to a 10.5% (95% CI, 5.1%-16.2%) increase in West Virginia. Average PrEP coverage ranged from 3.8% in West Virginia to 22.2% in New York.

Additionally, from 2012 to 2021, the quintile-specific change in HIV diagnosis rates ranged from a 1.7% increase (95% CI, –0.7% to 4.1%) in the lowest quintile of PrEP coverage to an 8% decrease (95% CI, –9.3% to 6.8%) in the highest quintile of PrEP coverage, after controlling for yearly changes in viral suppression rates.

“Clinical trials proved that PrEP works at the individual level. This analysis shows that PrEP works at a population level,” Sullivan said. “Clinicians should use HIV testing as an entry point to evaluate whether PrEP could be beneficial for patients who test HIV negative, and to provide linkage to services for HIV care for those living with HIV.”

Australian data

Additional data presented at CROI out of Australia showed similarly positive data on PrEP uptake and HIV incidence.

Nicholas A. Medland

“PrEP is highly effective in preventing HIV in clinical trials and also in large implementation studies. What we don’t know is if is just as effective population-wide when massively scaled up,” Nicholas A. Medland, PhD, a clinical epidemiologist at the University of New South Wales, told Healio. “This is key question as countries aim to eliminate HIV transmission in certain groups like gay and bisexual men.”

According to Medland, Australia has successfully and rapidly scaled up PrEP thanks to a highly accessible government subsidized scheme.

“Due to the fact that the government also subsidizes HIV treatment, we are able to measure new HIV diagnoses in people who have previously used PrEP — almost all of whom are gay or bisexual men — over the whole country over a 5-year period and to estimate HIV incidence and therefore the population effectiveness of PrEP,” he said.

Medland and colleagues assessed records for all government-subsidized PrEP and ART from April 2018 to June 2023 to identify HIV acquisition among PrEP users who initiated ART. They determined the date of HIV acquisition to be the midpoint between 30 days before ART initiation and either 6 months before or the most recent PrEP prescription. They then calculated days covered by PrEP and HIV incidence among people using PrEP, as well as any predictors, from April 2018 to December 2022.

Among 66,206 people who had received PrEP between April 2018 to March 2023, 207 acquired HIV during that time. Medland said the overall HIV incidence was low — 1.07 per 1,000 people per year, although it was higher in some groups, including patients who received PrEP once and never came back for a second supply (4.7-fold higher), patients who used PrEP less than 60% of the time (1.7-fold higher), patients who had been treated for hepatitis C (8.7-fold higher) and people aged younger than 30 years (1.6-fold higher).

Medland explained that the data show that taking PrEP more than 60% of the time reduced HIV incidence by 79%, whereas taking PrEP less than 60% of the time still reduced incidence by 62%.

“This is great news for PrEP programs expanding rapidly in the real world,” Medland said. “The overall incidence in reassuringly low.”

He noted some areas where improvements can be made — such as treating younger patients, and engaging people who do not return regularly for refills and those with hepatitis C risk factors — are becoming clear.

“Maybe it is time to think about a new model of care for PrEP: a model of ongoing engagement in preventive care, rather than a series of one-off clinical encounters initiated by the patient,” he said.

References:

  • Medland N, et al. Abstract 166. Presented at: Conference on Retroviruses and Opportunistic Infections; March 3-6, 2024; Denver.
  • Sullivan P, et al. Abstract 165. Presented at: Conference on Retroviruses and Opportunistic Infections; March 3-6, 2024; Denver.