Optimising scale-up for public health impact: a multimethod implementation science research protocol to improve infant health outcomes in Ethiopia.

Introduction: Child mortality rates remain high in sub-Saharan Africa, including Ethiopia. We are conducting a cluster randomised control trial in the Gondar zone of the Amhara region to determine the impact of pairing Orthodox priests with community health workers, known locally as the Health Development Army (HDA), on newborns' nutritional status, early illness identification and treatment, and vaccination completeness.Ensuring intervention efficacy with scientific rigour is essential, but there are often delays in adopting evidence into policy and programmes. Here, we present a protocol for conducting parallel implementation research alongside an efficacy study to understand intervention implementability and scalability. This will help develop a scale-up strategy for effective elements of the intervention to ensure rapid implementation at scale.

Methods And Analysis: We will conduct a stakeholder analysis of key implementation stakeholders and readiness surveys to assess their readiness to scale up the intervention. We will conduct semistructured interviews and focus group discussions with stakeholders, including HDA members, health workers, Orthodox priests, and caregivers, to determine the core intervention elements that need to be scaled, barriers and facilitators to scaling up the intervention in diverse sociocultural settings, as well as the human and technical requirements for national and regional implementation. Finally, to determine the financial resources necessary for sustaining and scaling the intervention, we will conduct activity-based costing to estimate implementation costs from the provider's perspective.

Ethics And Dissemination: The study received approval from the University of Gondar Institutional Review Board (approval no: VP/RTT/05/1030/2022) and the University of Washington Human Subjects Division (approval no: STUDY00015369). Participants will consent to participate. Results will be disseminated through workshops with stakeholders, local community meetings, presentations at local and international conferences, and journal publications. The study will provide evidence for factors to consider in developing a scale-up strategy to integrate the intervention into routine health system practices.