The goal of this clinical trial is to test the effectiveness and implementation of enhanced Secondary Antibiotic Prophylaxis (SAP) supports using a hybrid type 1 effectiveness-implementation design. The purpose is to determine whether enhanced SAP supports will increase average SAP adherence in Brazil and Timor-Leste. The study will enroll people living with Rheumatic Heart Disease (RHD) and Community Health Workers (CHWs) participating in the intervention.

The main questions it aims to answer are:

• Whether CHW-led supports delivered within the community improve mean SAP adherence at 12 months post-intervention.
• Whether the intervention demonstrates acceptability, feasibility, uptake and engagement.

Researchers will compare baseline and post-intervention SAP adherence data for the 12 months prior to and following intervention rollout to see if CHW-delivered supports increase adherence.

The first aim will utilize a non-controlled, pre-post design to evaluate CHW-led supports delivered within the community on SAP adherence. The composition of the SAP adherence supports will be finalized prior to implementation and will be comprised of a CHW-delivered package of supports covering patient reminders, education, and connection to care. The final package will reflect solutions that are easy for CHWs to deliver, acceptable to patients and families, and well aligned with local context, resources, and cultural norms. SAP adherence for the 12 months prior to and following intervention rollout will be captured from facility-based paper records, triangulated with prophylaxis cards of individual patients and the ACT registry once it is established at both sites. At enrollment, each participant will be assigned an anonymized study ID, and demographic data will be collected along with RHD history. CHWs in a ratio of approximately 1:10 patients will be selected for training, with training delivered through a standardized, competency-based curriculum including in-person workshops, practical skill-building sessions, and supervised field practice. Ongoing mentorship will be provided throughout the training period to ensure readiness, fidelity, and confidence before CHWs deliver the intervention.

The second aim will be guided by the Integrative Behavioral Model to examine implementation outcomes and mechanisms underlying behavior change related to SAP adherence. A subset of relevant constructs from the outer and inner setting domains of the Consolidated Framework for Implementation Research will augment the IBM. Participants will include people living with RHD, CHWs, and key informants. Quantitative data collection will include program activity logs completed weekly by participating CHWs and a patient knowledge and perception survey developed locally based on the General Attitudes Towards Medication Questionnaire with additional questions capturing IBM constructs. Semi-structured qualitative interviews will follow best practices, including recording with consent, post-interview debriefing, ongoing reflexivity memoing, and maintenance of detailed memos and field notes. Interview guides informed by the IBM and selected CFIR constructs will address perspectives related to acceptability, feasibility, uptake, and engagement.

Quantitative and qualitative analyses will occur in parallel. Descriptive statistics will summarize survey results and aggregate measures of patient engagement and CHW adoption. Joint displays will be constructed to visually compare qualitative and quantitative findings and examine convergence in themes or patterns. Qualitative data will be analyzed using thematic content analysis, with a codebook developed based on the IBM, CFIR, and open coding of initial interviews. All transcripts will be independently coded deductively by one study team member and reviewed by another, with disagreements resolved by consensus.

Inclusion Criteria:

• Adults living with rheumatic heart disease (RHD): age ≥18 years; diagnosed with RHD; prescribed secondary antibiotic prophylaxis (SAP)
• Guardians of children living with RHD: age ≥18 years; caregiver/guardian of a child aged 5-17 years with diagnosed RHD who is prescribed SAP
• Children living with RHD: age 12-17 years; diagnosed with RHD; prescribed SAP
• Community health workers (CHWs): age ≥18 years; associated with a healthcare center providing care to patients with RHD
• Healthcare workers (HCWs): age ≥18 years; employed at a healthcare center providing care to patients with RHD; able to provide informed consent in English or the local language

Exclusion Criteria:

• Adults living with RHD: medical contraindication to SAP; inability to provide informed consent (e.g., significant cognitive or communication impairment precluding participation)
• Guardians of children living with RHD: child has a medical contraindication to SAP; inability to provide informed consent
• Children living with RHD: medical contraindication to SAP; inability to provide informed assent (e.g., significant cognitive or communication impairment precluding participation)
• Community health workers: none
• Healthcare workers: none

The study population includes children, adolescents, and adults living with rheumatic heart disease (RHD), their caregivers, community health workers (CHWs), and healthcare workers (HCWs) in Brazil and Timor-Leste. Participants will be recruited from health centers and RHD registries within the public health systems.