Efficacy of a Just-in-Time Adaptive Intervention to Promote HIV Risk Reduction Behaviors Among Young Adults Experiencing Homelessness: Pilot Randomized Controlled Trial.

BACKGROUND: People experiencing homelessness have higher rates of HIV than those who are stably housed. Mental health needs, substance use problems, and issues unique to homelessness such as lack of shelter and transiency need to be considered with regard to HIV prevention. To date, HIV prevention interventions for young adults experiencing homelessness have not specifically addressed modifiable real-time factors such as stress, sexual or drug use urge, or substance use, or been delivered at the time of heightened risk. Real-time, personalized HIV prevention messages may reduce HIV risk behaviors. OBJECTIVE: This pilot study tested the initial efficacy of an innovative, smartphone-based, just-in-time adaptive intervention that assessed predictors of HIV risk behaviors in real time and automatically provided behavioral feedback and goal attainment information. METHODS: A randomized attention control design was used among young adults experiencing homelessness, aged 18-25 years, recruited from shelters and drop-in centers in May 2019. Participants were randomized to either a control or an intervention group. The intervention (called MY-RID [Motivating Youth to Reduce Infection and Disconnection]) consisted of brief messages delivered via smartphone over 6 weeks in response to preidentified predictors that were assessed using ecological momentary assessments. Bayesian hierarchical regression models were used to assess intervention effects on sexual activity, drug use, alcohol use, and their corresponding urges. RESULTS: Participants (N=97) were predominantly youth (mean age 21.2, SD 2.1 years) who identified as heterosexual (n=51, 52%), male (n=56, 57%), and African American (n=56, 57%). Reports of sexual activity, drug use, alcohol use, stress, and all urges (ie, sexual, drug, alcohol) reduced over time in both groups. Daily drug use reduced by a factor of 13.8 times over 6 weeks in the intervention group relative to the control group (Multimedia Appendix 4). Lower urges for sex were found in the intervention group relative to the control group over the duration of the study. Finally, there was a statistically significant reduction in reports of feeling stressed the day before between the intervention and control conditions (P=.03). CONCLUSIONS: Findings indicate promising intervention effects on drug use, stress, and urges for sex in a hard-to-reach, high-risk population. The MY-RID intervention should be further tested in a larger randomized controlled trial to further investigate its efficacy and impact on sexual risk behaviors. TRIAL REGISTRATION: ClinicalTrials.gov NCT03911024; https://clinicaltrials.gov/ct2/show/NCT03911024.

Factors Associated with Human Papillomavirus Vaccination among Women in the United States.

BACKGROUND: Human papillomavirus (HPV) infection is the most common sexually transmitted infection (STI) in the United States (US). HPV vaccines have the ability to prevent infection with HPV. The objective of this study was to assess the factors associated with HPV vaccination among women in the US. METHODS: Data from the 2014 Behavioral Risk Factor Surveillance System were used to assess predictors of HPV vaccination. A multivariable logistic regression analysis was used to estimate adjusted odds ratios (AORs) and 95% confidence intervals (95% CIs). Analyses were conducted using SAS Version 9.4. RESULTS: Factors that decreased the likelihood of receiving HPV vaccination included: being between the ages of 27-50 (AOR: 0.08; 95% CI: 0.06-0.11), having some college education, and residing in the South Black Belt States (AOR: 0.49; 95% CI: 0.31-0.78), Midwest (AOR: 0.63; 95% CI: 0.44-0.90), and the West (AOR: 0.37; 95% CI: 0.15-0.95). Factors that decreased the likelihood of receiving HPV vaccination to completion included: being Non-Hispanic Black (AOR: 0.26; 95% CI: 0.11-0.64), Hispanic (AOR: 0.26; 95% CI: 0.10-0.68), between the ages of 27-50 years (AOR: 0.46; 95% CI: 0.26-0.84), and residing in the Midwest (AOR: 0.36; 95% CI: 0.18-0.73) and South Remainder (non- Black Belt) states (AOR: 0.30; 95% CI: 0.09-0.93). CONCLUSION: Our results suggest that sociodemographic disparities still exist in more recent data underscoring the urgent need for additional efforts to increase HPV vaccination in populations that are least likely to receive the vaccination.

NMR-based Structural Analysis of Threonylcarbamoyl-AMP Synthase and Its Substrate Interactions.

The hypermodified nucleoside N(6)-threonylcarbamoyladenosine (t(6)A37) is present in many distinct tRNA species and has been found in organisms in all domains of life. This post-transcriptional modification enhances translation fidelity by stabilizing the anticodon/codon interaction in the ribosomal decoding site. The biosynthetic pathway of t(6)A37 is complex and not well understood. In bacteria, the following four proteins have been discovered to be both required and sufficient for t(6)A37 modification: TsaC, TsaD, TsaB, and TsaE. Of these, TsaC and TsaD are members of universally conserved protein families. Although TsaC has been shown to catalyze the formation of L-threonylcarbamoyl-AMP, a key intermediate in the biosynthesis of t(6)A37, the details of the enzymatic mechanism remain unsolved. Therefore, the solution structure of Escherichia coli TsaC was characterized by NMR to further study the interactions with ATP and L-threonine, both substrates of TsaC in the biosynthesis of L-threonylcarbamoyl-AMP. Several conserved amino acids were identified that create a hydrophobic binding pocket for the adenine of ATP. Additionally, two residues were found to interact with L-threonine. Both binding sites are located in a deep cavity at the center of the protein. Models derived from the NMR data and molecular modeling reveal several sites with considerable conformational flexibility in TsaC that may be important for L-threonine recognition, ATP activation, and/or protein/protein interactions. These observations further the understanding of the enzymatic reaction catalyzed by TsaC, a threonylcarbamoyl-AMP synthase, and provide structure-based insight into the mechanism of t(6)A37 biosynthesis.