An interventional study of Weekly WhatsApp Adherence Messages in HIV Infections, sponsored by Oswaldo Cruz Foundation. Recruiting at 1 site in Brazil. Open to male participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-19.
Sponsored by Oswaldo Cruz Foundation · Not applicable, Interventional, and Prevention
This study will create and follow an online cohort of sexual and gender minorities in Brazil to better understand the use of HIV prevention and treatment strategies, particularly pre-exposure prophylaxis (PrEP) and antiretroviral treatment (ART). Participants will complete online questionnaires at the beginning of the study and every three months for one year to provide information about medication use and adherence, sexual behaviors, HIV prevention and testing, sexually transmitted infections, mental health, and experiences of discrimination in health services.
Participants who are using PrEP or ART and agree to take part in the intervention will be randomly assigned to receive either a digital intervention or no digital intervention. The digital intervention will consist of weekly WhatsApp messages for six months, including reminders and information intended to support adherence to PrEP or ART.
The main question of the study is whether weekly WhatsApp messages can improve adherence to PrEP or ART among sexual and gender minorities in Brazil. The study hypothesis is that participants who receive the digital intervention will have higher adherence to PrEP or ART than participants who do not receive the intervention.
4,734 studies on the registry are indexed under HIV Infections; 244 are open to participants now.
This study's planned enrollment of 3,000 is above the median of 80 across 3,489 interventional studies indexed under HIV Infections.
Browse HIV Infections studies →Oswaldo Cruz Foundation is the lead sponsor of 42 studies on the registry; 7 are open to participants now.
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male sex assigned at birth and identifying as a man, travesti, transgender person, or non-binary person; age ≥18 years; residing in Brazil; access to the internet; and self-reporting sex with a man in the past 12 months.
Exclusion Criteria:
incorrectly answering the attention-check questions; and incomplete responses, defined as not reaching the end of the screening questionnaire
Participants receiving weekly WhatsApp messages for 6 months to support adherence to PrEP or ART, including medication reminders and brief standardized HIV prevention and treatment information.
Behavioral: Weekly WhatsApp Adherence Messages
Participants will receive the standard study follow-up procedures without the weekly WhatsApp adherence messages.
Participants randomized to the intervention arm will receive weekly WhatsApp messages for 6 months designed to support adherence to pre-exposure prophylaxis (PrEP) or antiretroviral therapy (ART). Messages will include medication reminders and brief, standardized information related to HIV prevention and treatment. Messages will be delivered through a scheduled automated system.
Medication Adherence to PrEP or ART
Medication adherence will be assessed using a visual analog scale in which participants report the percentage of prescribed PrEP or ART doses taken during the previous 30 days, from 0% to 100%. Participants reporting adherence greater than 95% will be classified as adherent. The primary analysis will compare the proportion of participants classified as adherent between the weekly WhatsApp intervention and control groups over follow-up.
Time frame: Baseline and Months 3, 6, 9, and 12
Medication Adherence to PrEP
Self-reported adherence to PrEP during the previous 30 days, measured using a 0% to 100% visual analog scale. Participants reporting adherence greater than 95% will be classified as adherent. Adherence will be evaluated over follow-up and compared between intervention and control groups among participants using PrEP.
Time frame: Baseline and Months 3, 6, 9, and 12
Started May 2026 (actual). Primary completion is estimated for Dec 2028, 31 months after the start.
Of 393 non-industry interventional studies with no phase under HIV Infections, half reached primary completion within 28 months of starting (the median), counting those still running; a quarter within 16 and three quarters within 45. This study's planned 31 months is above that.
Counting every sponsor, half of 402 studies reached it within 28 months; a quarter within 16 and three quarters within 45.
How these figures are worked out, and which studies are left out of them.
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Oswaldo Cruz Foundation