Mind the gap: implementation challenges break the link between HIV/AIDS research and practice

Risk assessment for HIV infection in men who have sex with men and the contribution of sexual partner networks

This study aimed to evaluate the risk of HIV infection in men who have sex with men (MSM) by developing an index that considers sex partner networks. The index variables were age, ethnicity/skin color, schooling, relationship type, condom use in receptive and insertive relationships, self-perception of the possibility of HIV infection, sexually transmitted infections, and rapid HIV testing results. We used data from a cross-sectional MSM egocentric network survey conducted in Rio de Janeiro between 2014 and 2015. The initial research volunteer is called ego, each partner is called alter, and each pair of people in a relationship is called the dyad. Multiple logistic regression was used to define the coefficients of the equations for the elaboration of the indices. The index ranged from 0 to 1; the closer to 1, the higher the risk of HIV infection. HIV prevalence was 13.9% among egos. The mean egos index with an HIV-reactive test was 57% higher than non-reactive, and the same profile was observed in the index values of dyads. The index allowed the incorporation of network data through the dyads and contributed to the identification of individuals with a higher likelihood of acquiring HIV.

Using data from 'visible' populations to estimate the size and importance of 'hidden' populations in an epidemic: A modelling technique

We used reported behavioural data from cisgender men who have sex with men and transgender women (MSM/TGW) in Bangalore, mainly collected from 'hot-spot' locations that attract MSM/TGW, to illustrate a technique to deal with potential issues with the representativeness of this sample. A deterministic dynamic model of HIV transmission was developed, incorporating three subgroups of MSM/TGW, grouped according to their reported predominant sexual role (insertive, receptive or versatile). Using mathematical modelling and data triangulation for 'balancing' numbers of partners and role preferences, we compared three different approaches to determine if our technique could be useful for inferring characteristics of a more 'hidden' insertive MSM subpopulation, and explored their potential importance for the HIV epidemic. Projections for 2009 across all three approaches suggest that HIV prevalence among insertive MSM was likely to be less than half that recorded in the surveys (4.5-6.5% versus 13.1%), but that the relative size of this subgroup was over four times larger (61-69% of all MSM/TGW versus 15%). We infer that the insertive MSM accounted for 10-20% of all prevalent HIV infections among urban males aged 15-49. Mathematical modelling can be used with data on 'visible' MSM/TGW to provide insights into the characteristics of 'hidden' MSM. A greater understanding of the sexual behaviour of all MSM/TGW is important for effective HIV programming. More broadly, a hidden subgroup with a lower infectious disease prevalence than more visible subgroups, has the potential to contain more infections, if the hidden subgroup is considerably larger in size.

Factors Associated with PrEP Refusal Among Transgender Women in Northeastern Brazil

Brazil has recently integrated HIV Pre-exposure Prophylaxis (PrEP) into its public health system and offered to key populations such as transgender women (TGW). This study investigates factors associated with PrEP refusal among TGW living in one of the largest and poorest cities of Brazil. We recruited 127 TGW using Respondent Driven Sampling (RDS) in Salvador, Brazil. Latent class analysis (LCA) was used to define acceptability of PrEP. Two latent classes were identified: "high acceptability of PrEP" (91.3%) and "PrEP refusal" (8.7%). PrEP was less acceptable among white TGW and among those age 25 or older, with income above minimum wage (≥ US$252.87), and reporting unprotected receptive anal intercourse with (URAI) causal partners. The findings highlight how nuanced strategies that takes into consideration unique characteristics are needed to effectively address the acceptability of PrEP.

Current research gaps: a global systematic review of HIV and sexually transmissible infections among transgender populations

Transgender populations are heavily burdened by HIV and other sexually transmissible infections (STIs). However, data on co-infection with HIV and STIs among transgender people are limited. A systematic review was conducted of peer-reviewed articles and conference abstracts between January 2010 and November 2015 that focussed on HIV and STI infections among transgender populations globally. The literature was synthesised and opportunities for improving health research were commented on. Few studies reported HIV-STI co-infection (n=4), while the majority of studies reported HIV and STI infections separately (n=23). Most studies were conducted outside of the USA (n=19), and all but one of these studies reported data on transgender women only. Among USA-based studies (n=8), several reported data on both transgender men and transgender women (n=3), whereas other studies reported exclusively on transgender men (n=1) or transgender women (n=4). Understanding HIV and STIs among transgender people requires research that simultaneously considers multilevel drivers of vulnerabilities. More data are needed on how the interaction of individual determinants, including biological risks of transmission, programmatic determinants such as service-delivery models and policy-level determinants including institutionalised stigma in healthcare settings, influence the HIV- and STI-related outcomes of transgender populations. Leveraging the knowledge of transgender-specific determinants of HIV and STIs should guide the content and approaches to future HIV and STI prevention and treatment efforts.