A real-time early warning system to anticipate respiratory disease outbreaks using transfer learning

Respiratory disease outbreaks burden American healthcare systems with over one million hospitalizations annually, yet current surveillance systems lag 1-2 weeks behind real-time conditions, preventing timely intervention. We present a machine learning early warning system that combines Google search trends with traditional epidemiological data using ensemble voting algorithms to predict outbreak timing across multiple respiratory pathogens. Unlike prior digital surveillance systems focused on retrospective evaluation or single-pathogen settings, this work presents a unified, prospectively deployed early warning framework that detects both outbreak onsets and peaks across multiple respiratory pathogens at the state level in real time. The system applies anomaly detection and transfer learning to monitor syndromic influenza-like illnesses, and hospitalizations caused by respiratory syncytial virus or influenza, simultaneously, across all 50 states. During operational real-time deployment from August 2024 through the 2024-2025 season, the system detects 98.0% of outbreak onsets and 97.0% of outbreak peaks, with average lead times of approximately 5 and 2 weeks, respectively, and positive predictive values exceeding 82%. This framework transforms reactive public health responses into proactive epidemic preparedness by reducing historical timing uncertainty from 10-20 weeks to consistent 2-6 week prediction windows, providing a scalable approach for monitoring both seasonal outbreaks and emerging respiratory threats.