When Professional Commitment Is Not Enough: Implementation Lessons from a RE-AIM-Guided Qualitative Study of Adolescent Primary Care Access in Brazil

Background/Objectives: Adolescents are among the least likely to receive primary health care (PHC), even where services are formally available. In Brazil, a companion quantitative evaluation of Chega Junto, a quality-improvement initiative in a socioeconomically vulnerable urban community, documented significant and sustained gains in adolescent access but could not explain how these gains were achieved or why they proved so difficult to sustain. This study examined health professionals’ implementation experiences, using the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation, Maintenance) to identify the conditions shaping adolescent access and its sustainability. Methods: Focus groups were conducted with 11 health professionals across three PHC units (Unidades Básicas de Saúde, UBS) in Paraisópolis, São Paulo, Brazil. Transcripts underwent inductive–deductive thematic analysis guided by RE-AIM, with reporting following the COREQ criteria; the study is the qualitative component of a mixed-methods evaluation. Results: Adolescent reach was built on trust-based therapeutic bonds and the explicit recognition of adolescents’ right to consult independently, rather than on increasing the number of outreach contacts. Formal goals, including vaccination, were met. Yet, unaddressed psychosocial and mental-health needs exposed the limits of a numerically bounded scope. Adoption was strong and grounded in participatory co-design, reorienting professionals toward adolescents as autonomous rights-holders. Implementation was enabled by intersectoral partnerships but undermined by productivity metrics that rendered relational work invisible. Conclusions: Adolescent PHC access depended on relational and organizational conditions that standard metrics fail to capture; sustaining it requires institutional redesign as a foundational precondition rather than an afterthought.