The St Louis Regional Pediatric Learning Collaborative of pediatric primary care providers and infectious diseases specialists formed in March 2020 to address the needs of children and families during the coronavirus disease 2019 (COVID-19) pandemic. More than 400 pediatric primary care providers participated, using a listserv to discuss care and organize webinars to provide updates on local and national data and plan next steps. To inform local decision-making about care and testing for severe acute respiratory syndrome coronavirus 2, 95 providers from 26 practices partnered with the local practice-based research network to rapidly collect and share data about children with COVID-19-like symptoms. Of 2162 children tested for severe acute respiratory syndrome coronavirus 2, 9% had positive test results. Test result positivity was 33% if a patient was exposed to a confirmed case of COVID-19 and 4% if they had COVID-19-like symptoms and no exposure. School or day care attendance was associated with lower rates of positive test results. Although not originally planned, these findings drove local advocacy efforts by the Collaborative for increased access to testing and contact tracing and safe in-person school. Members communicated directly and collectively with local politicians, provided advice and resources for school boards and superintendent groups, and appeared on various media platforms. In these efforts, they shared local data, highlighting the lower rate of positive test results for children in school to support the idea that schools could be safely open. Outreach from trusted pediatricians sharing prospective, timely, local data sustained in-person school for some districts and aided in future in-person openings for other school districts.