SPIRIT-C 2026 explanation and elaboration: recommendations for enhancing the reporting and usefulness of paediatric randomised trial protocols

Paediatric randomised controlled trials (RCTs) are key to evaluating new and existing interventions that can improve health outcomes in newborns, infants, children, and adolescents (aged 0-19 years). Well reported RCT protocols facilitate the planning and implementation of trials that generate high quality, reproducible evidence, and strengthen the foundations of paediatric healthcare decisions and ultimately improve patient outcomes. The Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2025 statement contains a checklist of essential reporting items and an explanation and elaboration paper. However, SPIRIT 2025 does not consider important elements that are unique to paediatric RCT protocols. As a paediatric extension to SPIRIT, we developed the SPIRIT-Children and Adolescents (SPIRIT-C) 2026 checklist, which this explanation and elaboration paper accompanies. We adopted a group writing approach to prepare this explanation and elaboration paper, and involved key partners with lived experience relevant to paediatric clinical trials, including family caregivers, trialists, child health researchers, clinicians, journal editors, and methodologists. This explanation and elaboration paper presents examples, explanations, and key elements for the 17 new SPIRIT-C 2026 reporting items; paediatric considerations with good reporting examples for six SPIRIT 2025 items; and a glossary. This paper also promotes the reporting of methodological rigor, patient safety, promotes a patient oriented approach, and facilitates the generation of high quality, reproducible trial evidence that will strengthen paediatric practice and policy decisions and ultimately improve patient outcomes.