Effective HIV Prevention Interventions and the Need for Rapid Mobilization to Address HIV Outbreaks Among At-Risk Populations.

The human immunodeficiency virus (HIV) epidemic continues to affect at-risk populations, including men who have sex with men (MSM) and persons who inject drugs (PWID). In 2015, >2.1 million new infections occurred worldwide, with a disproportionate number among MSM and PWID [1]. Despite these numbers, there is evidence that the epidemic is slowing down on a macro level. There has been an overall decrease in the number of new HIV diagnoses in many countries, including the United States [2]. This is largely owing to improved access to HIV testing and treatment, as well as prevention approaches, including pre-exposure prophylaxis. However, to fully address the HIV epidemic, improved approaches are needed to address micro-level HIV epidemics (ie, outbreaks). Outbreaks among vulnerable populations (eg, MSM and PWID) contribute to the larger-scale epidemic and propagation of HIV transmission. Among PWID, there are a number of effective substance use treatments and HIV prevention approaches, including syringe access programs, opioid replacement therapy, pre-exposure prophylaxis, routine HIV testing, and “treatment as prevention” for those who test positive [3]. Although the tools may be available to prevent HIV among PWID, how to implement these interventions in an effective and timely manner requires further study. In this issue of The Journal of Infectious Diseases, Sypsa et al [4] describe a “seek-test-treat” intervention (ARISTOTLE) that was implemented during 2012–2013 in response to an HIV outbreak among PWID in Athens, Greece [5]. The outbreak was initially described in 2011 [6]. At the time, Greece had very little circulating HIV among PWID [7]. There were also few harm reduction services for PWID [8]. In response to the epidemic, the number of clinical centers providing opioid treatment significantly increased, as did syringe access programs. The intervention, as described in the current article, also involved rapidly identifying as many PWID as possible, with the goal of providing HIV testing, clean syringes, condoms, opioid treatment, and linkage to HIV care and treatment for those who were HIV positive [5]. It used respondent-driven sampling to recruit PWID over a period of 16 months from 2012 to 2013. A total of 3320 unique PWID were engaged. Sypsa et al [4] estimated that this captured approximately 88% of all PWID in the Athens metropolitan area who had injected within the last month. They found a very high HIV prevalence (16.5%). Over time, HIV prevalence declined from 26% in the first round of respondent-driven sampling recruitment to 6% in the fifth round. During this time, the incidence of HIV infection decreased from 7.8 to 1.7 per 100 person-years, a 78% decrease. Risk factors associated with seroconversion included homelessness and incarceration. Over the time period of the intervention, injection frequency and needle sharing decreased. Although it is difficult to prove causation, these results strongly suggest that ARISTOTLE had an impact on reducing HIV incidence and keeping it low. The ARISTOTLE approach demonstrates the power of timely and effective implementation of structural-level HIV prevention approaches. Of particular importance was rapid mobilization. Many times, response to outbreaks is hampered by slow reporting mechanisms and subsequent delays in implementation of appropriate interventions. In ARISTOTLE, the rapid mobilization of resources included access to syringes, opioid replacement therapy, HIV testing, and linkage to care and treatment. This high-coverage, fast-track approach is consistent with recommendations by other international organizations [9, 10]. As the HIV epidemic matures, rapid response and implementation of appropriate interventions to stem outbreaks is needed, especially among at-risk populations, such as PWID and MSM. The ARISTOTLE approach was probably effective for several reasons. First, it focused on the entire HIV care continuum, including prevention, diagnosis, linkage to care, and treatment. Many times, interventions focus on only one aspect of the care continuum. E D I T O R I A L C O M M E N T A R Y