Developing mHealth to Promote PrEP Use Among Thai Young Vulnerable Adolescents and Emerging Adults

March 11, 2026 updated by: Bo Wang, University of Massachusetts, Worcester

Optimizing an mHealth Intervention to Improve Uptake and Adherence of the HIV Pre-exposure Prophylaxis (PrEP) in Vulnerable Adolescents and Emerging Adults

The main aim of this study is to develop technology-based interventions to improve HIV pre-exposure prophylaxis (PrEP) uptake and adherence among Thai young transgender women.

Study Overview

Detailed Description

Motivational Enhancement System for Adherence (MESA) is a computer-based motivation invention, based on the Information-Motivation-Behavioral Skills (IMB) model and Motivational Interviewing (MI) principles, used to promote adherence among HIV-positive youth initiating antiretroviral treatment. In this study, the team will adapt and develop MESA to focus on PrEP uptake and adherence, which will be called Motivational Enhancement System for PrEP Uptake and Adherence (MES-PrEP). YaCool is a mobile application developed to support transgender women self-management of gender and sexual health, including PrEP use.

In Aim 1, the investigators will begin with needs assessment to evaluate intervention efficacy by exploring the barriers and facilitators of PrEP uptake and adherence through in-depth interviews with transgender women and community health workers. The two interventions will be developed and refined based upon the inputs from transgender women through focus group discussion and community advisory board.

In Aim 2, the investigators will conduct a Multiphase Optimization Strategy (MOST) design-based trial to evaluate the feasibility, acceptability, and preliminary efficacy of MES-PrEP and Enhanced YaCool and to determine whether MES-PrEP works better when combined with Enhanced YaCool to improve PrEP use. Eligible transgender women will be randomized to one of the four experimental conditions, and followed for 12 months with assessments at baseline, month 1, 3, 6, 9 and 12.

Study Type

Interventional

Enrollment (Actual)

145

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Bangkok
      • Bangkok, Bangkok, Thailand, 10240
        • Rainbow Sky Association of Thailand
      • Bangkok, Bangkok, Thailand, 10330
        • Institute of HIV Research and Innovation
      • Bangkok, Bangkok, Thailand, 10500
        • SWING Foundation

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

16 years to 29 years (Child, Adult)

Accepts Healthy Volunteers

Yes

Description

Aim 1:

Transgender women participants

Inclusion Criteria:

  • Age 16-29 years old
  • Male sex at birth
  • Self-identifies as woman or transgender women or culturally identifies with the female spectrum
  • Confirmed HIV-negative status
  • Self-reported recent history of condomless sex in the past 6 months
  • Able to understand, read and speak Thai
  • Either having not started PrEP (Group 1: PrEP naive), currently on PrEP but not adherent to PrEP (taking ≤3 pills/week) in the past month (Group 2: PrEP users) or currently on PrEP with good adherence (Group 3: PrEP users with good adherence).

Exclusion Criteria:

  • Have a serious cognitive or psychiatric problem that would compromise ability to provide informed consent
  • Have active suicidal ideation or major mental illness (e.g., untreated psychosis or mania) at the time of interview (patients will be referred for treatment)
  • Laboratory or clinical findings that would preclude PrEP initiation (e.g., decreased creatinine clearance)

Healthcare providers

Inclusion Criteria:

  • Have at least 1-year experience working with HIV-negative transgender women, including providing PrEP prescription and counseling

Exclusion Criteria:

  • None

Aim 2:

Inclusion Criteria:

  • Age 16-29 years old
  • Male sex at birth
  • Self-identifies as woman or transgender women or culturally identifies with the female spectrum
  • Confirmed HIV-negative status
  • Self-reported recent history of condomless sex in the past 6 months
  • Able to understand, read and speak Thai
  • Either having not started PrEP (Group 1: PrEP naive), currently on PrEP but not adherent to PrEP (taking ≤3 pills/week) in the past month (Group 2: PrEP users).

Exclusion Criteria:

  • Have a serious cognitive or psychiatric problem that would compromise ability to provide informed consent
  • Have active suicidal ideation or major mental illness (e.g., untreated psychosis or mania) at the time of interview (patients will be referred for treatment)
  • Laboratory or clinical findings that would preclude PrEP initiation (e.g., decreased creatinine clearance)
  • Currently enrolled in another HIV intervention study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Factorial Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Standard PrEP Counseling, MES-PrEP and Enhanced YaCool
Participants in this arm will receive standard PrEP counseling, followed by two mHealth interventions (MES-PrEP and Enhanced YaCool) to improve PrEP uptake and support PrEP adherence.
MES-PrEP is a two-session computer-delivered intervention based on IMB model. The intervention is tailored based on the person's ratings of perceived importance and confidence of initiating PrEP and sustaining adherence to PrEP. Participants are routed to different intervention content based on their assessment of their importance and confidence. Youth are provided with feedback on scores on the knowledge assessment followed by information about protective effect that can result from improved PrEP adherence. Finally, participants are asked to set a goal: obtain PrEP prescription, optimal adherence, practice steps, or thinking about it more, and they form plans for overcoming barriers. In the second session, branches are based on whether the youth felt they met the goal, partially met the goal, or did not meet the goal. Sessions of MES-PrEP will occur at baseline and month 1.
Enhanced YaCool is mobile application developed to support transgender women self-management of their gender and sexual health, including PrEP use. YaCool is a passcode-protected app that allows users to personalized text messaged reminders to take PrEP and/or clinic appointments, record PrEP adherence and sexual activity, and track lab tests. The application is set up to provide personalized recommendations for PrEP regimen, confirmed by clinic healthcare staff. Participants will be asked to download Enhanced YaCool to support PrEP use and gender/sexual health self-management between MES-PrEP sessions for 30 days, and thereafter until the end of Month 12 (if desired).
All participants will received one-on-one, face to face counseling from lay providers at baseline, months 1, 3, 6, 9 and 12. Standard PrEP counseling includes sexual and behavioral risk assessment for HIV/STIs and risk reduction. For those not on PrEP, the sessions will focus on risk perception, awareness of PrEP/post-exposure prophylaxis (PEP) and facilitators and barriers of accessing PrEP. For those on PrEP, the sessions will focus on adherence. Standard counseling sessions will be nonjudgmental, non-discriminatory and client-centered.
Experimental: Standard PrEP Counseling and MES-PrEP
Participants in this arm will receive standard PrEP counseling, followed by one mHealth intervention (MES-PrEP) to improve PrEP uptake and support PrEP adherence.
MES-PrEP is a two-session computer-delivered intervention based on IMB model. The intervention is tailored based on the person's ratings of perceived importance and confidence of initiating PrEP and sustaining adherence to PrEP. Participants are routed to different intervention content based on their assessment of their importance and confidence. Youth are provided with feedback on scores on the knowledge assessment followed by information about protective effect that can result from improved PrEP adherence. Finally, participants are asked to set a goal: obtain PrEP prescription, optimal adherence, practice steps, or thinking about it more, and they form plans for overcoming barriers. In the second session, branches are based on whether the youth felt they met the goal, partially met the goal, or did not meet the goal. Sessions of MES-PrEP will occur at baseline and month 1.
All participants will received one-on-one, face to face counseling from lay providers at baseline, months 1, 3, 6, 9 and 12. Standard PrEP counseling includes sexual and behavioral risk assessment for HIV/STIs and risk reduction. For those not on PrEP, the sessions will focus on risk perception, awareness of PrEP/post-exposure prophylaxis (PEP) and facilitators and barriers of accessing PrEP. For those on PrEP, the sessions will focus on adherence. Standard counseling sessions will be nonjudgmental, non-discriminatory and client-centered.
Experimental: Standard PrEP Counseling and Enhanced YaCool
Participants in this arm will receive standard PrEP counseling, followed by one mHealth intervention (Enhanced YaCool) to improve PrEP uptake and support PrEP adherence.
Enhanced YaCool is mobile application developed to support transgender women self-management of their gender and sexual health, including PrEP use. YaCool is a passcode-protected app that allows users to personalized text messaged reminders to take PrEP and/or clinic appointments, record PrEP adherence and sexual activity, and track lab tests. The application is set up to provide personalized recommendations for PrEP regimen, confirmed by clinic healthcare staff. Participants will be asked to download Enhanced YaCool to support PrEP use and gender/sexual health self-management between MES-PrEP sessions for 30 days, and thereafter until the end of Month 12 (if desired).
All participants will received one-on-one, face to face counseling from lay providers at baseline, months 1, 3, 6, 9 and 12. Standard PrEP counseling includes sexual and behavioral risk assessment for HIV/STIs and risk reduction. For those not on PrEP, the sessions will focus on risk perception, awareness of PrEP/post-exposure prophylaxis (PEP) and facilitators and barriers of accessing PrEP. For those on PrEP, the sessions will focus on adherence. Standard counseling sessions will be nonjudgmental, non-discriminatory and client-centered.
Active Comparator: Standard PrEP Counseling
Participants in this arm will receive the standard PrEP counseling.
All participants will received one-on-one, face to face counseling from lay providers at baseline, months 1, 3, 6, 9 and 12. Standard PrEP counseling includes sexual and behavioral risk assessment for HIV/STIs and risk reduction. For those not on PrEP, the sessions will focus on risk perception, awareness of PrEP/post-exposure prophylaxis (PEP) and facilitators and barriers of accessing PrEP. For those on PrEP, the sessions will focus on adherence. Standard counseling sessions will be nonjudgmental, non-discriminatory and client-centered.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Intervention Acceptability: System Usability Score
Time Frame: Month 3
System Usability Score (SUS) is a 10-item, Likert scale used to calculate intervention usability. Each item ranges from 0 to 4 (with 4 being the most positive response). For odd-numbered items, the score is calculated by subtracting one from the user response. For even-numbered items, the score is calculated by subtracting the user response from 5. Then sum the total score and multiply that by 2.5. The overall SUS scores range from 0 to 100. A score of > 50 indicates that the technology-based interventions are acceptable.
Month 3
Intervention Acceptability: System Usability Score
Time Frame: Month 6
System Usability Score (SUS) is a 10-item, Likert scale used to calculate intervention usability. Each item ranges from 0 to 4 (with 4 being the most positive response). For odd-numbered items, the score is calculated by subtracting one from the user response. For even-numbered items, the score is calculated by subtracting the user response from 5. Then sum the total score and multiply that by 2.5. The overall SUS scores range from 0 to 100. A score of > 50 indicates that the technology-based interventions are acceptable.
Month 6
Intervention Acceptability: Client Satisfaction Questionnaire
Time Frame: Month 3
Client Satisfaction Questionnaire (CSQ-8) is an 8-items, Likert scale measuring the construct of global intervention satisfaction. The total possible composite score range from 8 to 32, with higher scores indicating a greater degree of acceptability.
Month 3
Intervention Acceptability: Client Satisfaction Questionnaire
Time Frame: Month 6
Client Satisfaction Questionnaire (CSQ-8) is an 8-items, Likert scale measuring the construct of global intervention satisfaction. The total possible composite score range from 8 to 32, with higher scores indicating a greater degree of acceptability.
Month 6
Intervention Acceptability: Exit Interview
Time Frame: Month 1
Intervention acceptability will be assess by the number of positive responses based on the exit interviews administered at month 1. Participants will be asked to provide feedback on experiences using MES-PrEP and enhanced YaCool, acceptability and ease of use, suggestions for improvement, role in PrEP uptake and adherence, and interest in continued intervention use, as well as experiences following a PrEP regimen, reasons for discontinuation of PrEP, and additional tools that would assist them in taking PrEP.
Month 1
Intervention Feasibility: Number of responses to text messages
Time Frame: Baseline through Month 12
Intervention feasibility will be measured by total number of responses to and frequency of usage of Enhanced YaCool. Point estimates of >50% of participants responded to Enhanced YaCool at least once is considered as the minimum criteria for feasibility.
Baseline through Month 12
Intervention Feasibility: Number of intervention sessions completed
Time Frame: Baseline through Month 12
Intervention feasibility will be measured by number of intervention sessions completed. Point estimates of >50% of participants completed at least one intervention session is considered as the minimum criteria for feasibility.
Baseline through Month 12
Intervention Feasibility: Participant retention
Time Frame: Baseline through Month 6
Intervention Feasibility will be measured by participants retention rate at Month 6. Retention rate of >85% at month 6 is considered as the minimum criteria for feasibility.
Baseline through Month 6
PrEP Adherence: Visual analog scale
Time Frame: Baseline through Month 12
PrEP adherence will be measured from Young Adult Adherence Interview via computer-assisted self-interview (CASI) survey which contains a visual analog scale (VAS). VAS ranges from 0 to 100, with higher percentage indicating greater adherence to PrEP.
Baseline through Month 12
PrEP Adherence: Self-reported adherence
Time Frame: Baseline through Month 12
PrEP adherence will be measured from self-reported adherence to PrEP in the past 4 weeks via CASI survey. The scale ranges from 0 to 100%, with higher percentage indicating greater adherence to PrEP. The result of this self-reported adherence will be triangulated with the results of dried blood spots testing.
Baseline through Month 12
PrEP Adherence: Dried blood spots
Time Frame: Baseline through Month 12
PrEP adherence will be measured by the level of tenofovir in dried blood spots (DBS). DBS report on 80% Truvada adherence after at least three weeks of regular adherence.
Baseline through Month 12
PrEP Uptake
Time Frame: Month 1 through Month 12
PrEP uptake will be measured by the number of PrEP prescription, using a self-report measure (participants reporting if they left the clinic with PrEP) and confirming with clinic records.
Month 1 through Month 12

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
PrEP Knowledge
Time Frame: Baseline to Month 12
Knowledge of PrEP will be measured using the 13-item PrEP knowledge scale. The total possible score is 13, with higher scores indicating a greater degree of PrEP knowledge.
Baseline to Month 12
HIV Knowledge
Time Frame: Baseline to Month 12
Knowledge of HIV transmission risk will be assessed using am 18-item HIV Knowledge Questionnaire. The total possible composite score range from 0 to 18, with higher scores indicating a greater degree of HIV knowledge.
Baseline to Month 12
Motivation: Rollnick's Readiness Ruler
Time Frame: Baseline to Month 12
Behavioral intentions will be measured using 5-item Rollnick's Readiness Ruler, which correspond to PrEP uptake and adherence. Each item ranges from 0 to 10, with higher numbers indicate greater readiness for change.
Baseline to Month 12
Motivation: Decisional Balance for PrEP Use
Time Frame: Baseline to Month 12
Attitude towards PrEP will be measured using 36-item Decisional Balance for PrEP Use. The 5-point Likert scale assesses the pros and cons of PrEP use and is helpful in understanding cognitive and motivational aspects of decision making.
Baseline to Month 12
Behavior skills
Time Frame: Baseline to Month 12
Behavior skills will be assessed using the 8-item adapted version of Self-Efficacy for Health Promotion and Risk Reduction Questionnaire. The 5-point Likert scale assesses the confidence in using a condom, taking PrEP as recommended and getting PrEP refills. The total possible score is 40, with higher scores indicating a greater confidence for each item.
Baseline to Month 12
HIV Status
Time Frame: Baseline to Month 12
HIV status based on 4th generation HIV-1/2 antigen/antibody combo testing.
Baseline to Month 12
Sexually Transmitted Infections (STIs) Diagnosis
Time Frame: Baseline to Month 12
STI diagnosis based on treponemal test with rapid plasma reagin (RPR) confirmation for syphilis. Pooled urine, oropharyngeal and rectal swabs for gonorrhea and chlamydia nucleic acid amplification test (NAAT) testing.
Baseline to Month 12
Sexual Risk
Time Frame: Baseline to Month 12
Sexual risk will be assessed through Timeline Followback via CASI, which collects sexual behavior in the past 30 days, including questions about condom use and number of sexual partners.
Baseline to Month 12

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Drug/Alcohol Use: ASSIST
Time Frame: Baseline to Month 12
Drug/Alcohol Use will be assessed using Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) developed by the World Health Organization (WHO). ASSIST is a questionnaire that is used for identification of substance use related health risks and substance use disorders. Each item ranges from 0-12, with 0 reflecting low risk score. The total possible score is 24, with higher number indicating higher risk of health and other problems based from the current pattern of substance use.
Baseline to Month 12
Drug/Alcohol Use: AUDIT-C
Time Frame: Baseline to Month 12
Alcohol Use Disorders Identification Test (AUDIT-C) or a brief alcohol screening instrument will also be used to identify persons who are hazardous drinkers or have active alcohol use disorders (including alcohol abuse or dependence). Each item ranges from 0 to 4, with 0 reflecting no alcohol use. The total possible score is 12, with higher number indicating higher drink above recommended limits and are at increased risks for harm.
Baseline to Month 12
Mental Health
Time Frame: Baseline to Month 12
Mental Health will be assessed using the 12-item Thai General Health Questionnaire. The 4-point Likert scale measures psychological distress such as depression, anxiety, social impartment and somatic complaints. The total possible score is 48, with higher scores indicating higher severity of psychological distress.
Baseline to Month 12
Perceived HIV risk
Time Frame: Baseline to Month 12
Perceived HIV risk will be measured using the 8-item Perceived Risk of HIV Scale. All items are rated on a 4-point Likert scale. The total possible score is 40, with higher scores indicating higher perception of HIV risk.
Baseline to Month 12
Social support
Time Frame: Baseline to Month 12
Social support will be assessed using the 13-item Social Provision Scale (SPS). The 5-point Likert scale measures the availability of social support, including emotional support, information support, instrumental support, companionship and social isolation. The total possible score is 65, with higher scores indicating greater availability of social support.
Baseline to Month 12
PrEP stigma
Time Frame: Baseline to Month 12
PrEP-related stigma will be assessed using the 10-item PrEP stigma and positive attitudes scale. The 5-point Likert scale measures opinions about PrEP. Higher scores indicate higher perceived stigma related to PrEP.
Baseline to Month 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 27, 2021

Primary Completion (Actual)

January 31, 2026

Study Completion (Estimated)

July 31, 2026

Study Registration Dates

First Submitted

February 7, 2022

First Submitted That Met QC Criteria

February 17, 2022

First Posted (Actual)

March 2, 2022

Study Record Updates

Last Update Posted (Actual)

March 13, 2026

Last Update Submitted That Met QC Criteria

March 11, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • H00023527
  • 1R21HD107988-01 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

All IPD collected during the trial, after deidentification.

IPD Sharing Time Frame

Immediately following publication. No end date.

IPD Sharing Access Criteria

Anyone who wises to access the data.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • CSR

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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