Deep metric learning-based image retrieval system for chest radiograph and its clinical applications in COVID-19

•Development of a content-based image retrieval system for chest radiograph based on a novel deep metric learning algorithm.•Validation on an international multi-site COVID-19 dataset with superior performance in image retrieval, diagnosis and prognosis tasks.•Good transferability and generalizability on other clinical decision support tasks in the treatment and management of COVID-19 patient.•Being implemented in clinical workflow at Partners Healthcare due to high clinical impact for COVID-19 diagnosis, prognosis and patient management.