Behavior Change Among HIV-Negative Men Who Have Sex with Men Not Using PrEP in the United States.

This study measures changes in condomless anal sex (CAS) among HIV-negative men who have sex with men (MSM) who are not taking pre-exposure prophylaxis (PrEP). It considers the 2014-2019 cycles of the American Men's Internet Survey, a serial, cross-sectional web-based survey of US cisgender MSM aged ≥ 15 years, in which ~ 10% of each year's sample is drawn from the previous year. Among those surveyed for 2 years who remained HIV-negative and off PrEP, reports of having any CAS and of CAS partner number were compared across years. We disaggregated by partner HIV status, and considered demographic predictors. The overall population saw a significant 2.2 percentage-point (pp) increase in reports of any CAS year-over-year. Sub-populations with the largest year-on-year increases were 15-24-year-olds (5.0-pp) and Hispanic respondents (5.1-pp), with interaction (young Hispanic respondents = 12.8-pp). On the relative scale, these numbers correspond to 3.2%, 7.2%, 7.3% and 18.7%, respectively. Absolute increases were concentrated among partners reported as HIV-negative. Multivariable analyses for CAS initiation found effects concentrated among Hispanic and White youth and residents of fringe counties of large metropolitan areas. CAS partner number increases were similarly predicted by Hispanic identity and young age. Although condom use remains more common than PrEP use, increasing CAS among MSM not on PrEP suggests potential new HIV transmission pathways. Concentration of increases among 18-24-year-old MSM portends future increases in the proportion of newly diagnosed HIV that occur among youth. Concentration among young Hispanic MSM will likely expand existing disparities. Although reducing barriers to PrEP remains vital, condom promotion for MSM remains a key public health practice and appears to be missing key audiences. LGBTQ+-inclusive sex education is one avenue for enhancing these efforts.

High Seroprevalence of Hepatitis C Virus Among Cisgender Women Who Exchange Sex in the Seattle, Washington Area.

BACKGROUND: Injection drug use (IDU) is a risk factor for hepatitis C virus (HCV) acquisition and occurs disproportionately among women who exchange sex (WES). However, little is known about HCV epidemiology in this population. We estimated HCV seroprevalence, identified correlates of HCV seropositivity, and characterized social networks by HCV serostatus and IDU history among WES in the Seattle, Washington, area. METHODS: This was a secondary analysis of data from the 2016 National HIV Behavioral Surveillance survey in the Seattle, Washington area, a cross-sectional survey that used respondent-driven sampling (RDS) to enroll WES for money or drugs (N = 291). All participants were offered rapid HCV-antibody testing. We estimated HCV seropositivity and used log regression methods to estimate crude and adjusted prevalence ratios (PRs) for correlates of HCV seropositivity among WES. Using RDS recruitment chain data, we computed homophily indices to estimate the extent to which participants were likely to recruit another participant with the same HCV serostatus and IDU history. RESULTS: In the study sample of WES in the Seattle, Washington area, 79% reported lifetime IDU and 60% were HCV seropositive. HCV seropositivity was strongly associated with ever injecting drugs (PRadj: 7.7 [3.3, 18.0]). The RDS homophily scores for HCV seropositivity (0.07) and ever injecting drugs (0.02) suggested that participants did not tend to recruit others with the same characteristics beyond what would be expected by chance. CONCLUSION: Among this sample of WES in Seattle, Washington area, HCV seroprevalence was high and strongly associated with a history of IDU. The high burden of HCV among WES suggests this marginalized group would benefit from additional harm reduction services and targeted HCV treatment campaigns to reduce forward transmission. We saw little evidence of preferential recruitment among WES who were HCV seropositive or reported a history of IDU, suggesting the potential futility of peer-based referrals for HCV treatment.

Benefits of thermal and distance-filtered imaging for wayfinding with prosthetic vision.

Visual prostheses such as the Argus II provide partial vision for individuals with limited or no light perception. However, their effectiveness in daily life situations is limited by scene complexity and variability. We investigated whether additional image processing techniques could improve mobility performance in everyday indoor environments. A mobile system connected to the Argus II provided thermal or distance-filtered video stimulation. Four participants used the thermal camera to locate a person and the distance filter to navigate a hallway with obstacles. The thermal camera allowed for finding a target person in 99% of trials, while unfiltered video led to confusion with other objects and a success rate of only 55% ([Formula: see text]). Similarly, the distance filter enabled participants to detect and avoid 88% of obstacles by removing background clutter, whereas unfiltered video resulted in a detection rate of only 10% ([Formula: see text]). For any given elapsed time, the success rate with filtered video was higher than with unfiltered video. After 90 s, participants' success rate reached above 50% with filtered video and 24% and 3% with normal camera in the first and second tasks, respectively. Despite individual variations, all participants showed significant improvement when using the thermal and distance filters compared to unfiltered video. Adding a thermal and distance filter to a visual prosthesis system can enhance the performance of mobility activities by removing clutter in the background, showing people and warm objects with the thermal camera, or nearby obstacles with the distance filter.