The COVID-19 pandemic highlighted flaws in the global public health surveillance infrastructure and unveiled the challenges of timely outbreak detection, efficient cross-border coordination, and quick responses to novel health threats. As a revolutionary federated AI framework for creating new pandemic intelligence and pre-emptive intervention capacities, this paper introduces HealthVigil. Privacy-preserving federated learning techniques are used by HealthVigil models to train together without needing any agency or institutions to centralize patients’ sensitive data. Using datasets ranging from clinical records, genomic sequences, social media signals, mobility patterns, and environmental factors, HealthVigil provides a thorough early warning system to detect potential outbreaks before they propagate to epidemics. Our framework incorporates three key innovations: (1) The distributed anomaly detection system detects abnormal disease patterns while ensuring compliance with data sovereignty and privacy regulations; (2) an explainable AI module that provides transparent insights to public health officials, enhancing trust and facilitating timely decision-making; and (3) a cross-border coordination protocol that enables secure information sharing and collaborative response planning between nations while maintaining local governance. Using historical data from past outbreaks, HealthVigil can pinpoint 43 days sooner when pandemics are underway and offer the leading time to take early intervention action. Its federated architecture significantly reduces to 37 percent the otherwise impracticable false alarm rates of isolated systems, all while addressing ethical issues and regulatory impediments that have prohibited the international sharing of health data. The implementation challenges we discuss are data standardization, algorithmic fairness for diverse populations, and governance frameworks to enable global adoption. HealthVigil is a significant step in building a more potent global health infrastructure that could avert future pandemics by collaborating to sense and respond—the earlier, the better.