Date Published: January 10, 2018
Publisher: Public Library of Science
Author(s): Jeanne M. Marrazzo, Julia C. Dombrowski, Kenneth H. Mayer
Abstract: Jeanne M. Marrazzo and colleagues join PLOS Medicine’s Collection on the prevention, diagnosis, and treatment of STIs with a Perspective on HIV research imperatives in our time of effective viral suppression and pre-exposure prophylaxis.
Partial Text: Incident chlamydia, gonorrhea, and syphilis have risen sharply among men in the United States and other industrialized countries, with syphilis disproportionately high among MSM. Reports of gonorrhea at the rectal and pharyngeal sites are increasing disproportionately compared to urethral sites, partially due to enhanced screening of extragenital sites. This may be coincident with increased frequency of unprotected anal sex: in San Francisco, increasing proportions of MSM reported condomless anal sex in the preceding 12 months in the National Health Behavior Study from 2005–2014, and persons attending sexually transmitted disease clinics during the years 2007–2013 reported increases in the number of recent male sex partners . Motivation for decreased condom use may include confidence that use of ARV for prevention attenuates transmission risk or the belief that HIV is no longer a serious health concern.
There is an urgent need to optimize new advances in ART-based HIV treatment and prevention to reduce incident STI and to explicitly outline the key questions informing the path forward (Table 1). First, the relationship between HIV biology in the anogenital compartments compared to blood is not completely understood. Notably, most studies evaluating HIV genital shedding have identified RNA copies of HIV by nucleic acid amplification, but less is known about replication-competent, intracellular or extracellular transmissible virus. Ultrasensitive assays to detect minute amounts of P24 protein or replication-competent virions may help to clarify this . Can local genital inflammation mediated by soluble immune mediators facilitate breakthrough local replication of the virus despite systemic control that could promote the risk of transmission? Given the success of ART in significantly decreasing sexual transmission of HIV, even in the presence of high STI incidence, it seems likely that breakthrough shedding on suppressive ART will not be a major contributor to the ongoing transmission of HIV.
In the era of biomedical HIV prevention, STIs are increasing in many populations, offering new challenges and opportunities. PrEP has introduced a tension between HIV and STI prevention that needs to be articulated and confronted: condomless sex is becoming more frequent, and anxiety about HIV acquisition risk can be considerably lessened. That STI incidence is increasing concurrent with the positive, affirming aspects of PrEP and TasP is a reality that should be recognized as an opportunity to promote sexual health, embrace diversity of sexual expression, and develop creative, efficient, comprehensive approaches to the study of STIs for the next decade. This will entail reexamination of the research priorities that span funding organizations, as well as allocation of funding in its current form. Studies primarily aimed at biomedical HIV prevention should incorporate efficient designs to include STI as well as HIV. Finally, it will be critical to engage communities in an active dialogue to advance mutual understanding of how these disease trends are perceived, studied, and managed.