HIV Self-testing With Online Supervision for Vietnamese MSM
Phase: NA
Conditions: HIV
Sponsor: Mahidol University

Study protocol: HIV self-testing with online supervision 
(STOS) for Vietnamese MSM 
 
Authors: Thomas E Guadamuz, Worawalan Waratworawan, Yamol Kongjareon, Giang Minh 
Le, Lan Anh Thi Do 
 
IDENTIFIERS 
 
MAHIDOL Ethic Project ID  
2021/119.2010 
Full (Scientific) title 
HIV self-testing with online supervision 
(STOS) for Vietnamese MSM 
Study Type 
Interventional 
Target sample size 
100 
STUDY TIMELINES 
 
Study Duration 
01/07/2021-30/06/2025 
Expected Start Date for Cohort Recruitment 
05/01/2023 
End of Study Date 
05/21/2025 
KEY STUDY CONTACTS 
 
1. Assoc. Prof. Thomas E Guadamuz, 
Mahidol Center for Health, Behavior 
and Society Faculty of Tropical 
Medicine, Mahidol University  
2. Worawalan Waratworawan, Mahidol 
Center for Health, Behavior and 
Society Faculty of Tropical Medicine, 
Mahidol University   
3. Yamol Kongjareon, Mahidol Center 
for Health, Behavior and Society 
Faculty of Tropical Medicine, Mahidol 
University 
4. Prof. Giang Minh Le, Center for 
Training and Research on Substance 
Abuse and HIV and School of 
Preventive Medicine and Public 
Health, Hanoi Medical University  
5. Dr. Lan Anh Thi Do, Department of 
Epidemiology, Faculty of Public 
Health, Pham Ngoc Thach University 
of Medicine Ho Chi Minh City 
STUDY SPONSOR 
 
National Institute of Mental Health (NIMH) 
KEY WORDS 
 
YMSM, HIV/AIDS, STOS, Vietnam, HIV self-
testing, online supervision 
 

 
2 
 
Table of Contents 
Study protocol: Addressing the Continuum of Care Among High-risk Thai Men ................ 1 
1. Introduction .......................................................................................................................... 3 
1.1 Overview of the Problem ................................................................................................ 3 
1.2 Supporting Evidence ...................................................................................................... 3 
1.3 Rationale for This Study ................................................................................................ 3 
1.4 Objective ......................................................................................................................... 3 
2. Study design and methods of data collection ................................................................... 4 
2.1 Procedures ...................................................................................................................... 5 
2.1.1 Recruitment and Enrollment ....................................................................................... 5 
2.1.2 Data Collection ........................................................................................................... 5 
2.1.3 Retention and Engagement Strategies ....................................................................... 6 
2.2 Eligibility criteria ............................................................................................................. 6 
2.3 Consent ........................................................................................................................... 7 
2.3.1 Consent Procedures .................................................................................................. 7 
2.3.2 Withdrawal/discontinuation criteria ............................................................................. 7 
2.4 Data analysis .................................................................................................................. 7 
2.5 Assessment and management of risk ........................................................................... 9 
2.6. Data management .......................................................................................................... 9 
2.7 Recording and reporting of risk events and incidents ................................................ 9 
3. Funding ................................................................................................................................10 
4. Monitoring and auditing ..................................................................................................... 11 
5. Publication and dissemination ........................................................................................... 11 
6. References........................................................................................................................... 11 
7. Annexes ...............................................................................................................................14 
7.1 Participants Information Sheet .....................................................................................15 
7.2 Informed Consent Script ...............................................................................................15 
7.3 Statistical Analysis Plan (SAP) .....................................................................................15 
 
 
 
 

 
3 
1. Introduction 
1.1 Overview of the Problem 
HIV infection among men who have sex with men (MSM) in Vietnam continues to rise, 
with prevalence in Ho Chi Minh City (HCMC) estimated at 17% and incidence among young 
MSM (YMSM) in Hanoi at 5.8%.1 Behavioral risks such as unprotected sex, multiple partners, 
and untreated STIs sustain high levels of circulating virus within MSM networks.22-25 Low HIV 
testing rates and poor engagement in care further exacerbate transmission.7 Meanwhile, 
widespread smartphone and internet use among Vietnamese MSM offers an opportunity for 
online testing innovations.8,9,10 
1.2 Supporting Evidence 
National surveillance shows that HIV prevalence among MSM increased from 6.2% in 
2006 to 14% in 2009 in HCMC, reaching 19% nationwide by 2011.1 Epidemiological studies 
identify consistent risk factors including low HIV knowledge,11 sexual risk and STIs,22-25  identity- 
and stigma-related challenges,12,13 and limited access to appropriate health services.7 A 
Vietnam-based survey found that 76.5% of MSM had never been voluntarily tested for HIV.14 
Evidence from Thailand demonstrates that an online HIV testing (OHT) model achieved 90% 
retention and 100% linkage to care.15,16 Additionally, 97% of Vietnamese MSM report HIV self-
testing as acceptable.10 
1.3 Rationale for This Study 
Persistent barriers such as stigma, low perceived risk, and fear of disclosing same-sex 
behaviour continue to limit HIV testing among Vietnamese YMSM.12,13,8,9 Increasing HIV testing 
is essential for achieving the UNAIDS 90-90-90 goals, which require individuals at high risk to 
test at least annually.17 Online HIV self-testing with real-time supervision can overcome 
institutional and psychological barriers while ensuring linkage to treatment or prevention.8,9,10 
Building on successful online HIV self-testing with online supervision (STOS) implementation in 
Thailand,15,16 adapting this model for Vietnam could substantially increase testing uptake and 
reduce HIV incidence.18,19 
1.4 Objective 
Aim 1: To conduct focus group discussions to identify potential barriers and facilitators to the 
uptake of online HIV testing among YMSM in Ho Chi Minh City 
Aim 2: To adapt the existing Thai online HIV self-testing with online supervision intervention for 
use among YMSM in Vietnam, willingness to engage in online HIV self-testing with online 
supervision as well as factors related to sustained testing will be collected through an online 
survey 
Aim 3: To demonstrate the feasibility and acceptability of the adapted online HIV self-testing with 
online supervision (STOS) intervention, including use of an HIV rapid diagnostic 
antibody/antigen-based self-testing with an HIV counselor through video conferencing 

 
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2. Study design and methods of data collection 
This study aims to evaluate the effectiveness of the HIV self-testing with online 
supervision (STOS) intervention, which includes the introduction of a HIV rapid diagnostic 
antibody/antigen-based self-testing conducted with the support of a trained counsellor via video 
conferencing, among young men who have sex with men (YMSM) aged 16–29 years. 
The study employs a pilot randomized controlled trial (RCT) design with two groups: an 
intervention group (STOS) and a control group. The total sample size is 100 participants (50 per 
group). The follow-up period spans 12 months, with data collected at three time points: baseline, 
6 months, and 12 months. 
Data collection includes self-administered online questionnaires completed through the 
Qualtrics platform.20 For participants in the intervention group, the study involves the 
implementation of real-time online supervised HIV self-testing conducted by a trained counsellor 
through video conferencing.  

 
5 
2.1 Procedures 
2.1.1 Recruitment and Enrollment 
Participant recruitment will be conducted over a one-year period, using a combination of 
online and offline outreach strategies to reach the target population of young men who have sex 
with men (YMSM) in Ho Chi Minh City.  
For the online cross-sectional survey, recruitment will primarily be conducted through 
online platforms, including Google advertisements, Facebook, the CARMAH fan page, 
CARMAH networks, other MSM community networks, and youth networks in Ho Chi Minh City 
(such as university and high school students). To encourage participation, each respondent will 
receive a mobile top-up e-voucher valued at 50,000 VND (approximately 2 USD), delivered via 
SMS. 
Individuals interested in participating will complete an online eligibility screening form. 20 
Those who meet the inclusion criteria will receive detailed study information and proceed with 
the initial electronic consent (e-consent). After completing the survey, if an individual is found to 
be HIV-positive, they will not be invited to participate in the pilot study. 
For the pilot study, a total of 100 Vietnamese YMSM will be recruited and followed for 12 
months. Participants will be randomly assigned into two groups of 50 each: 
• 
The intervention group, which will receive the HIV self-testing with online supervision 
(STOS) intervention; and 
• 
The control group, which will refer to the standard of care, consisting of a voucher for 
venue-based HIV testing. 
The STOS program begins when a counsellor contacts eligible participants via the Zalo 
communication platform. After confirming eligibility, the counsellor obtains verbal informed 
consent and schedules an appointment for the HIV self-testing with online supervision (STOS) 
session. 
Once the appointment is confirmed, HIV self-testing kits are delivered to participants through 
Be Delivery service. Before the testing session, participants receive a link to an instructional 
YouTube video developed by CARMAH and Mahidol University, which demonstrates the correct 
procedure for performing the HIV self-test. 
During the scheduled session, the counsellor provides pre-test counselling and real-time 
supervision via video conferencing as participants perform the self-test. This process ensures 
proper use of the test kit, supports accurate interpretation of results, and maintains participant 
confidentiality throughout the HIV self-testing process. 
2.1.2 Data Collection 

 
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Data collection will occur at three time points: at baseline and again at 6 and 12 months 
of follow-up. During each assessment, participants will complete self-administered 
questionnaires on tablets or smartphones via the Qualtrics platform. For individuals assigned to 
the STOS group, HIV self-testing outcomes will be documented by a trained counselor and 
stored in an encrypted file with restricted access. Only the Principal Investigator (PI) and the 
Study Statistician will be authorized to view these data to maintain strict confidentiality. 
All study data will be housed on secure institutional servers in encrypted, password-
protected formats to ensure robust data security. 
2.1.3 Retention and Engagement Strategies 
To ensure sustained participation throughout the follow-up period, the research team will 
implement continuous engagement measures using multiple digital communication channels, 
including the Zalo application, SMS, telephone calls, and support from community peer leaders. 
Participants will be contacted regularly to receive project updates, appointment reminders, and 
encouragement to take part in each data-collection round. Ongoing assistance will also be 
provided to help maintain participants’ motivation and consistency in completing questionnaires. 
For the STOS group, follow-up communication will additionally ensure that participants receive 
their self-testing kits. These combined strategies are expected to achieve follow-up retention 
rates exceeding 80% at each assessment point. 
2.2 Eligibility criteria 
Inclusion Criteria: 
• 
Aged between 16 and 29 years 
• 
Have been residing in Ho Chi Minh City for more than 6 months 
• 
Assigned male at birth or intersex 
• 
Self-identify as men who have sex with men (MSM), Homosexual, bisexual, or male 
(straight) 
• 
Have engaged in anal sex (insertive or receptive) with a male partner within the past 6 
months 
• 
Willing and able to provide informed consent to participate in the study 
Exclusion Criteria: 
• 
Aged ≤15 years or ≥30 years 
• 
Have been residing in Ho Chi Minh City for less than 6 months or do not currently live in 
Ho Chi Minh City. 
• 
Assigned female at birth 
• 
Self-identify as a woman, transgender woman, or transfeminine individual 
• 
Unwilling to participate in follow-up activities associated with the study 
 
2.3 Consent 
2.3.1 Consent Procedures 
All participants will provide informed consent by clicking “accept button” at the time they begin 
the online survey. For participants under 18 years of age, a waiver of parental consent will be 
obtained from the ethics committee to protect them from the potential risk of unintentional 

 
7 
disclosure of their sexual orientation or HIV status. Before joining the study, participants will 
receive a study information sheet explaining the research objectives and procedures. This 
document will appear immediately before the consent question in the online survey, allowing 
participants to review the study details before providing consent. After completing the survey, 
participants who are interested in joining the STOS intervention will be introduced to additional 
information, as follows: Participants will be informed that the study involves an online HIV self-
testing intervention and that they may be randomly assigned to one of two testing approaches.  
The first approach involves receiving an HIV home self-testing kit, with real-time 
guidance and support from trained staff via video calls and instructional videos. The second 
approach involves receiving information about free HIV testing services available at public 
hospitals, where participants can go for testing independently. If selected for participation, study 
staff will contact participants using the contact information provided to explain further details and 
confirm their willingness to take part. For those who are randomly assigned to the STOS group, 
multiple formats will be used to ensure a full understanding of study procedures. These include 
printed materials, instructional videos (e.g., how to perform HIV self-testing), and verbal 
explanations provided by trained counsellor. Participants will be encouraged to ask questions 
about any aspect of the study, including the survey process, HIV self-testing procedures, and 
their right to withdraw from the study at any time without penalty or loss of benefits. Informed 
consent will be obtained only after participants demonstrate clear understanding and express 
their willingness to participate voluntarily. At each follow-up round, field staff will reassess 
participants’ understanding and verbally reconfirm consent before administering questionnaires 
or conducting STOS sessions, to ensure that participants remain fully informed and voluntarily 
engaged throughout the longitudinal study 
2.3.2 Withdrawal/discontinuation criteria  
Participants could withdraw from the study at any time and for any reason. Withdrawal 
did not affect the compensation they had already received or their access to HIV-related 
services. Common reasons for discontinuation included being unreachable, or unwillingness to 
continue participation. 
2.4 Data analysis 
Both descriptive and inferential statistical methods will be employed to evaluate the 
effectiveness of the STOS intervention throughout the study period. Analyses will compare the 
STOS intervention group and the control group across demographic variables, behavioral 
measures, and health-related outcomes associated with HIV infection. 
2.4.1 Descriptive Analyses 
Baseline characteristics of participants, including demographic, behavioral, and health-
related information, will be summarized using descriptive statistics, stratified by study group 
(intervention vs. control) to assess baseline differences between the two groups and changes 
over time. Categorical variables will be presented as frequencies and percentages, while 
continuous variables will be summarized using means and standard deviations (mean ± SD) or 
medians with interquartile ranges (IQR: 25th–75th percentile), depending on the data 
distribution. 

 
8 
2.4.2 Primary and Secondary Outcome Analyses 
To evaluate the effects of the STOS intervention, two groups will be compared: the 
STOS group, who receive an HIV self-testing kit and complete the online questionnaires, and 
the control group, who complete the questionnaires only. The primary outcomes are the rate of 
HIV testing uptake and the rate of new HIV infections during the study period. The secondary 
outcomes include changes in sexual behaviors, mental health, and other psychosocial 
indicators over time. To assess the effects of the intervention across time points, Generalized 
Estimating Equations (GEE) models will be applied, using a log link function for rate outcomes 
and an identity link function for continuous outcomes. The models will include variables for study 
arm (STOS vs. control), time (follow-up round), and their interaction term (arm × time) to 
estimate longitudinal intervention effects. Robust standard errors will be used to account for 
within-subject correlation due to repeated measures. The results will be presented as Rate 
Ratios (RRs or Incidence Rate Ratios, IRRs) with 95% confidence intervals (CIs) and p-values 
to indicate the magnitude and statistical significance of the observed effects. 
2.4.3 Multiple Comparisons and p-value Adjustment 
When multiple comparisons are made, such as in subgroup analyses or secondary 
outcomes, adjustments to p-values will be considered to control for the risk of type I error. 
Methods such as Bonferroni correction or false discovery rate (FDR) adjustment will be applied 
as appropriate. 
2.4.4 Statistical Software 
All data analyses will be conducted using STATA version 18.0,21 which is the primary 
statistical software used by the research team for data management, descriptive analyses, 
regression modeling, and longitudinal data analysis. 

 
9 
2.5 Assessment and management of risk 
This study will be conducted as a low-risk observational cohort study. However, certain 
items in the questionnaire, such as those related to sexual behavior or HIV status, may be 
considered sensitive. To minimize potential risks, several protective measures will be 
implemented. All data will be collected anonymously and stored securely using an encrypted 
system with restricted access, ensuring that no personally identifiable information is recorded. 
Participants will be informed of their right to skip any question they find uncomfortable 
and their right to withdraw from the study at any time without any negative consequences. 
Additionally, counsellor will provide continuous support by explaining study procedures and 
addressing participants’ questions throughout the study period. If necessary, participants will be 
referred to mental health or HIV-related services for appropriate care. 
In cases where participants are found to be HIV positive, they will receive preliminary 
counseling and be referred to appropriate healthcare facilities for further testing and treatment in 
accordance with the Ministry of Public Health guidelines. 
A Data and Safety Monitoring Board (DSMB) will also be established to oversee the 
project’s risk management strategies, monitor participant safety and well-being, and ensure 
continuous ethical compliance. The DSMB will operate independently to review study 
procedures and provide recommendations to the research team regarding any necessary 
protocol adjustments to maintain ethical and safety standards throughout the study. 
2.6. Data management 
Data collection will be carried out through the Qualtrics platform, where key items will be 
configured with mandatory responses and skip logic will be applied to ensure that participants 
are directed only to questions relevant to their previous answers. Once data collection is 
completed, the dataset will be exported, cleaned, and analyzed using STATA software. 
Participant records across follow-up periods will be matched using the nicknames and 
phone numbers provided to the research team. All identifying information will be safeguarded 
through a dual-encryption system and stored on secure, password-protected servers maintained 
by Mahidol University. Access to these data will be limited to authorized study personnel, 
including the Principal Investigator (PI) and designated data managers responsible for 
overseeing data handling procedures. 
2.7 Recording and reporting of risk events and incidents 
If an adverse or risk-related event occurs during the study, the research team will 
systematically document and review the incident. Key information, including the type of event, 
the time it occurred, the individuals involved, and any immediate actions taken, will be recorded.
 
The research team will evaluate the seriousness of the incident and determine the 
appropriate follow-up steps. Any event deemed serious or potentially compromising participant 
safety will be promptly reported to the Data and Safety Monitoring Board (DSMB) for 
independent assessment and recommendations. These incidents will also be submitted to the 
Institutional Review Board (IRB) within the required reporting window in accordance with ethical 
guidelines. 

 
10
Clear procedures are in place to ensure that all incidents are handled in a timely, 
transparent, and appropriate manner. All incident documentation will be securely stored and 
treated as confidential. Participants may also communicate any concerns or discomfort to the 
research team through the confidential communication channels routinely used in the study, 
including Zalo and telephone contact. 
3. Funding 
This study is funded by the National Institute of Mental Health (NIMH), under Grant 
R34MH123337. 

 
11
4. Monitoring and auditing 
The Principal Investigator (PI) will oversee the full implementation of the study and 
ensure that all procedures align with the approved protocol and applicable ethical standards. 
Local field activities and data collection will be carried out with support from the Center for 
Applied Research on Men and Community Health (CARRMAH), a trusted community-based 
partner located in Ho Chi Minh City. 
A Community Advisory Board (CAB) will contribute guidance on participant recruitment 
approaches and study operations to ensure meaningful community engagement and cultural 
appropriateness. Four CAB consultations were conducted and included representatives from 
NGOs such as HAIVN, community-based organizations including TestSGN, CARMAH, G3VN, 
and Galant clinics, as well as HIV testing and counseling staff and young men who have sex 
with men (YMSM). 
Regular internal monitoring will be performed by the core coordination team to check 
data accuracy, review informed consent processes, and verify adherence to study procedures, 
including pre- and post-test counseling, data handling practices, and confidentiality safeguards. 
The Data and Safety Monitoring Board (DSMB) will independently review study progress, safety 
reports, and any risk events at scheduled intervals. The DSMB may also conduct audits to 
evaluate compliance with the protocol, ethical standards, and data quality. Three DSMB 
meetings were conducted with participation from the following experts: Dr. Kanokwan Chair, 
PhD in Anthropology, Institute for Population and Social Research at Mahidol University; Dr. 
Giang Truong Le, PhD in Public Health and former Deputy Director of the Ho Chi Minh City 
Department of Health, now serving as President of the Vietnam Public Health Association and 
Consultant at Pham Ngoc Thach University of Medicine; and Dr. Truc Thai Thanh, PhD in Health 
Sciences and Vice Head of the Biostatistics and Informatics Department, Faculty of Public 
Health, University of Pharmacy and Medicine in Ho Chi Minh City.  
All monitoring and auditing outcomes will be documented, and any deviations from the 
protocol will be addressed through appropriate corrective measures. Required reports will be 
submitted to the IRB and the DSMB, and all follow-up actions will be tracked to maintain 
ongoing quality assurance throughout the study. 
5. Publication and dissemination 
Study findings will be disseminated through peer-reviewed publications and 
presentations at national and international conferences, following all ethical and reporting 
standards to ensure participant confidentiality. Summary results will also be shared with key 
stakeholders, including local health authorities, NGOs, service providers, and community-based 
organizations. Plain-language summaries and aggregated participant updates will be prepared 
to improve accessibility for non-academic audiences. 
Given the intervention-focused nature of the study, the research team will engage 
multisectoral partners—such as government agencies, public health institutions, and community 
networks—to support the translation of findings into practice and explore opportunities for scale-
up. Policy briefs may be developed to inform decision-making at local and national levels. Digital 
platforms may also be used to distribute summaries or infographics where appropriate. 

 
12
The Community Advisory Board (CAB) will provide input to ensure culturally appropriate 
dissemination strategies. Authorship will follow international guidelines (e.g., ICMJE), and all 
dissemination materials will be reviewed and approved by the Principal Investigator before 
release. 
 
6. References 
1. National Committee for AIDS, Drug, and Prostitution Prevention and Control, Hanoi 
Vietnam. Viet Nam AIDS Response Progress Report 2014. Accessed August 15, 2019. 
https://www.aidsdatahub.org/Vietnam-Global-AIDS-Response-Progress-Report-2014 
2. Nguyen TA, Nguyen HT, Le GT, Detels R. Prevalence and risk factors associated with HIV 
infection among men having sex with men in Ho Chi Minh City, Vietnam. AIDS Behav. 
2008;12(3):476-482. doi:10.1007/s10461-007-9267-y 
3. Ngo AD, Ross MW, Ratliff EA. Internet influences on sexual practices among young people 
in Hanoi, Vietnam. Culture, Health & Sexuality. 2008;10(sup1):S201-S213. 
doi:10.1080/13691050701749873 
4. Colby D, Minh TT, Toan TT. Down on the farm: homosexual behaviour, HIV risk and HIV 
prevalence in rural communities in Khanh Hoa province, Vietnam. Sex Transm Infect. 
2008;84(6):439-443. doi:10.1136/sti.2008.031294 
5. Vu BN, Girault P, Do BV, Colby D, Tran LTB. Male sexuality in Vietnam: the case of male-to-
male sex. Sex Health. 2008;5(1):83-88. 
6. Pham Q, Thuong Þ, Nguyen T, et al. Prevalence of HIV/STIs and associated factors among 
men who have sex with men in An Giang, Vietnam. Sexually transmitted diseases. 2012;39. 
doi:10.1097/OLQ.0b013e318265b180 
7. Mimiaga MJ, Closson EF, Biello KB, et al. A Group-Based Sexual Risk Reduction 
Intervention for Men Who Have Sex With Men in Ho Chi Minh City, Vietnam: Feasibility, 
Acceptability, and Preliminary Efficacy. Arch Sex Behav. 2016;45(6):1493-1500. 
doi:10.1007/s10508-015-0663-5 
8. Green KE, Vu BN, Phan HT, et al. From conventional to disruptive: upturning the HIV testing 
status quo among men who have sex with men in Vietnam. J Int AIDS Soc. 2018;21(Suppl 
Suppl 5). doi:10.1002/jia2.25127 
9. Hoang HT, Mai TDA, Nguyen NA, et al. Needs Assessment on the Use of Health Services 
Among Men Who Have Sex with Men in Ho Chi Minh City, Vietnam. LGBT Health. 
2015;2(4):341-345. doi:10.1089/lgbt.2015.0034 
10. PATH. HIV Self-Testing in Vietnam. July 2018. Accessed September 8, 2019. 
https://www.path.org/resources/hiv-self-testing-in-vietnam/ 
11. Vian T, Semrau K, Hamer DH, Loan LTT, Sabin LL. HIV/AIDS-Related Knowledge and 
Behaviors Among Most-at-Risk Populations in Vietnam. Open AIDS J. 2012;6:259-265. 
doi:10.2174/1874613601206010259 

 
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12. Ha H, Risser JMH, Ross MW, Huynh NT, Nguyen HTM. Homosexuality-Related Stigma and 
Sexual Risk Behaviors Among Men Who Have Sex With Men in Hanoi, Vietnam. Arch Sex 
Behav. 2015;44(2):349-356. doi:10.1007/s10508-014-0450-8 
13. Goldsamt LA, Clatts MC, Giang LM, Yu G. Prevalence and Behavioral Correlates of 
Depression and Anxiety Among Male Sex Workers in Vietnam. Int J Sex Health. 
2015;27(2):145-155. doi:10.1080/19317611.2014.947055 
14. García MC, Duong QL, Mercer LE, Meyer SB, Ward PR. ‘Never testing for HIV’ among Men 
who have Sex with Men in Viet Nam: results from an internet-based cross-sectional survey. 
BMC Public Health. 2013;13:1236. doi:10.1186/1471-2458-13-1236 
15. Guadamuz T, Samoh N, Teachatanawat N, et al. “It’s easy and convenient!”: Perceived 
facilitators and barriers for HIV self-testing and PrEP uptake among adolescent men who 
have sex with men, transgender women and their parents. In: 2019. 
16. Samoh N, Guadamuz T. “If not for online testing, I would never get tested”: Willingness for 
online HIV testing among app-using YMSM in Bangkok. 
17. WHO. Consolidated guidelines on HIV testing services. WHO. 2015. Accessed September 
8, 2019. http://www.who.int/hiv/pub/guidelines/hiv-testing-services/en/ 
18. UNAIDS. Global AIDS update 2019 - Communities at the centre. Accessed August 15, 2019. 
https://www.unaids.org/en/resources/documents/2019/2019-global-AIDS-update 
19. World Health Organization. Guidelines on HIV Self-Testing and Partner Notification: 
Supplement to Consolidated Guidelines on HIV Testing Services.; 2016. 
https://apps.who.int/iris/bitstream/handle/10665/251655/9789241549868-
eng.pdf;jsessionid=3C4E10DDCF6EAC52E4A48B7C136A3768?sequence=1 
20. Qualtrics [computer program]. Published online 2019. https://www.qualtrics.com 
21. StataCorp. Stata Statistical Software. Published online 2023. 
22.  Ngo AD, Ross MW, Ratliff EA. Internet influences on sexual practices among young people 
in Hanoi, Vietnam. Cult Health Sex. 2008;10(sup1):S201-S213. 
doi:10.1080/13691050701749873 
23.  Colby D, Minh TT, Toan TT. Down on the farm: homosexual behaviour, HIV risk and HIV 
prevalence in rural communities in Khanh Hoa province, Vietnam. Sex Transm Infect. 
2008;84(6):439-443. doi:10.1136/sti.2008.031294 
24.  Vu BN, Girault P, Do BV, Colby D, Tran LTB. Male sexuality in Vietnam: the case of male-to-
male sex. Sex Health. 2008;5(1):83-88. 
25.  Pham Q, Thuong Þ, Nguyen T, et al. Prevalence of HIV/STIs and associated factors among 
men who have sex with men in An Giang, Vietnam. Sex Transm Dis. 2012;39. 
doi:10.1097/OLQ.0b013e318265b180 
26. Little RJA, Rubin DB. Statistical Analysis with Missing Data. John Wiley & Sons; 2014. 
27. Hedeker D, Gibbons RD. Application of random-effects pattern-mixture models for missing 
data in longitudinal studies. Psychol Methods. 1997;2(1):64-78. doi:10.1037/1082-989X.2.1.64. 

 
14
7. Annexes 
7.1 Participant Information Sheet 
 
 
 
 

 
15
 

 
 

 
17
 

 
18
 
7.2 Informed Consent Script 
 

 
 
 
7.3 Statistical Analysis Plan (SAP) 
Study Title: HIV self-testing with online supervision (STOS) for Vietnamese MSM 
ClinicalTrials.gov Identifier (NCT Number): NCT05797961 
Document Date: 01/01/2022 
 

 
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1. Introduction 
1.1 Objectives of the Statistical Analysis Plan 
The primary objective of this Statistical Analysis Plan (SAP) is to prospectively define the 
analytical framework, statistical methods, and procedures that will be used to analyze data from 
the clinical study titled “HIV self-testing with online supervision (STOS) for Vietnamese MSM”. 
This SAP is designed to ensure that the analysis is transparent, reproducible, and aligned with 
the registered study protocol under ClinicalTrials.gov Identifier NCT05797961. 
This SAP is intended to: 
• 
Describe the planned analyses for the primary and secondary study objectives 
• 
Specify the statistical techniques and data handling procedures to be used 
• 
Define the analysis populations 
• 
Outline approaches to address missing data, conduct sensitivity analyses, and 
implement subgroup analyses 
 
1.2 Background and Significance of the Study 
This study aims to evaluate the effectiveness of the STOS intervention in: 
• 
Increasing the frequency of HIV testing (at least once every six months) 
• 
Reducing sexual risk behaviors 
The study is conducted as a pilot randomized controlled trial (pilot RCT) using a longitudinal 
cohort design among young men who have sex with men (YMSM Cohort, N = 100) residing in 
Ho Chi Minh City, Vietnam, with participants randomized into two groups: the STOS intervention 
group and the control group. 
Given that YMSM in Ho Chi Minh City, Vietnam continue to have low rates of HIV testing, a 
high burden of HIV, and face structural and behavioral barriers to accessing healthcare 
services, this study is of significant public health importance and holds meaningful implications 
for national HIV policy development and prevention programming. 
2. Study Design Overview 
This study is a pilot randomized controlled trial (pilot RCT) using a longitudinal cohort 
design among young men who have sex with men (YMSM) aged 15–29 years, with a total of 
100 participants equally allocated into two groups: 
• 
STOS intervention group (n = 50) 
• 
Control group (n = 50) 
Participants will be followed for a period of 12 months, with data collection conducted at 
three times: baseline, 6 months, and 12 months of follow-up. 
 
2.1 Data Collection and Sources 
Data will be obtained through an online, self-completed survey administered via the 
Qualtrics platform, which participants can access on mobile phones or tablets. To protect 
confidentiality, the survey will not gather any personal identifiers. Participants will instead log in 
using the same chosen nickname or pseudonym and their approved contact method, enabling 
the research team to reliably match their responses across multiple survey waves without 
compromising anonymity. 
 
2.2 Retention and Follow-up 

 
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To maintain strong participant retention throughout the study, the research team will 
employ ongoing engagement activities delivered through digital communication channels and 
peer-supported community networks. 
3. Study Objectives and Endpoints 
3.1 Primary Objective 
To evaluate the effectiveness of the STOS intervention in increasing access to and 
uptake of HIV testing among young men who have sex with men (YMSM). 
 
3.2 Secondary Objectives 
• 
To evaluate the effect of the intervention on reducing the incidence of HIV infection. 
• 
To evaluate the effect of the intervention on reducing sexual risk behaviors (e.g., 
condomless anal intercourse with male partners). 
• 
To evaluate the effect of the intervention on reducing health-related risk behaviors, 
including mental health problems (depression and suicidal risk) and substance use. 
 
3.3 Primary Outcome 
• 
HIV testing uptake: 
Proportion of participants who report having tested for HIV at least once within a 6-
month period, based on STOS testing records and self-reported survey data. 
 
3.4 Secondary Outcomes 
• 
HIV incidence: 
Number of new HIV infections per 100 person-years, based on STOS testing results and 
self-reported data during follow-up. 
• 
Sexual risk behavior: 
Proportion of participants reporting condomless anal intercourse with male partners 
during the past 6 months, measured through self-reported survey data. 
• 
Health-related risk behaviors (mental health and substance use): 
Proportion of participants reporting mental health problems (e.g., depressive symptoms, 
suicidal risk) and frequency of substance use during the past 6 months, based on self-
reported survey data. 
4. Analysis Populations 
4.1 Intention-to-Treat (ITT) Population 
The ITT population will consist of all individuals who completed the baseline assessment 
and were allocated to either the intervention or control condition, independent of their 
subsequent engagement with any intervention components. This group will be used as the 
primary sample for assessing intervention effectiveness, aligning with a real-world evaluation 
approach that accounts for variations in actual participation. 
5. Data Management and Quality Assurance 
5.1 Handling of Missing Data 

 
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Data will be collected through an online Qualtrics survey20 with required-response items 
and programmed skip logic to minimize missing data at baseline. Despite these measures, 
some missingness is expected across follow-up rounds due to participant drop-out or missed 
assessments. All missing values will be clearly coded in the dataset. 
For analysis, we will examine differences between participants with complete and 
incomplete data. When missingness is substantial, multiple imputation (MI) or maximum 
likelihood (ML) methods will be applied under the missing-at-random (MAR) assumption.26 
Sensitivity analyses using pattern-mixture models will be conducted to assess the robustness of 
this assumption.27 Complete-case analysis may be used when missing data are minimal. 
5.2 Data Cleaning and Preparation 
After exporting the data from Qualtrics, the research team will conduct structured 
cleaning procedures using STATA21 command scripts to ensure accuracy and consistency. Key 
tasks will include identifying outliers, detecting logically inconsistent answers, checking the 
correctness of skip patterns, and verifying that numerical variables fall within acceptable ranges. 
Variables that depend on previous responses will also be reviewed to confirm internal 
coherence. 
For the preparation of the analytic dataset, information from two sources will be 
combined: (1) the self-administered online questionnaires collected through Qualtrics, and (2) 
HIV self-testing outcomes obtained from participants in the STOS intervention group. These 
datasets will be harmonized before merging. To ensure accurate linkage across time points, 
participants will be asked to provide the same nickname or pseudonym during every round of 
data collection. 
5.3 Variable Coding and Labeling 
All variables will be coded and labeled according to a standardized data dictionary to 
ensure consistency across all study rounds. Dichotomous variables will use fixed coding (e.g., 1 
= Yes, 0 = No), and Likert-scale items will follow predefined response categories. Maintaining 
uniform coding conventions will facilitate accurate interpretation, allow meaningful comparisons 
over time, and improve the reproducibility of the analyses. 
6. Statistical Methods 
6.1 Descriptive Analysis 
Descriptive statistics will be used to summarize baseline characteristics and study 
variables, separated by study arm: the STOS intervention group and the control group. 
Statistical comparisons will be performed between these two groups to evaluate the effects of 
the STOS intervention over time. Categorical variables will be presented as frequencies and 
percentages, while continuous variables will be summarized as means with standard deviations 
(mean ± SD) or medians with interquartile ranges (IQRs), depending on the data distribution. 
6.2 Primary and Secondary Outcome Analyses 
Generalized Estimating Equations (GEE) with appropriate link functions (e.g., logit for 
binary outcomes, identity for continuous variables) will be applied to assess intervention effects 

 
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over time. Each model will include study arm, follow-up time, and an interaction term to estimate 
differential changes between groups. Robust standard errors will be used to account for 
correlations within individuals. Person-time will also be calculated, and rate ratios with 95% 
confidence intervals will be reported. 
6.3 Multiple Comparisons and p-value Adjustment 
For secondary outcomes and subgroup analyses involving several statistical tests, 
adjustments for multiple comparisons will be applied as appropriate. Methods such as 
Bonferroni correction or false discovery rate (FDR) procedures will be considered to control the 
risk of type I error. 
6.4 Statistical Software 
All statistical analyses will be performed in STATA version 18.0, which will be used for 
data management, descriptive analysis, regression modeling, and longitudinal analyses. 
7. Sensitivity Analyses 
Sensitivity analyses will be conducted to evaluate the robustness of the results under 
alternative assumptions. These may involve varying model specifications, use alternative link 
functions, or compare findings from GEE models with those from mixed-effects models.