Surveillance systems provide essential early warning mechanisms that detect emerging threats to patient safety, product quality, and public health. Unlike periodic assessments that provide point-in-time snapshots, surveillance tools enable continuous monitoring, real-time data collection, and rapid response to evolving challenges. WHO supports global surveillance networks and information systems that track adverse drug reactions, antimicrobial resistance patterns, substandard and falsified medical products, medicine utilization trends, vaccine safety signals, and disease-specific outcomes.

Effective surveillance systems are critical for protecting patient safety in an increasingly complex and globalized pharmaceutical market. They enable rapid detection of safety concerns, quality defects, or supply disruptions; facilitate coordinated international responses; generate evidence to guide policy and clinical practice; and build confidence in health systems by demonstrating commitment to ongoing vigilance and accountability.

WHO's list of surveillance networks and alert newsletters related to medicines and health technologies are listed below.