This report discusses the importance of pharmacovigilance (PV) in contributing to building up resilient health systems. It is based on and summarizes the findings of a review of available literature on the topic and relevant case studies focusing on a set of country and regional experiences. Although indispensable in improving health outcomes, the administration and use of medicines may produce adverse reactions, requiring continuous monitoring to ensure that the benefits outweigh the risks. PV, which involves the systematic detection, reporting, assessment, understanding, and prevention of adverse drug reactions (ADRs), is an essential public health function, but it is often overlooked. The review suggests that successful PV programs are built on three essential pillars: statutory provisions that establish standards for PV centers and programs, well-trained health professionals and associated stakeholders, and engaged PV reporters using effective reporting systems. These pillars allow PV programs to be effective in three core activities: reporting adverse drug events (ADEs) and identifying signals, determining threats through a benefit-risk balance analysis, and taking appropriate actions. This is in addition to supporting various functions of a health system, such as national drug policy and regulation, the delivery of medical care, specific disease control programs, increasing the trust of the general public in the system, and promoting eco-PV. Aided by emerging opportunities for development through automation and machine learning, PV programs show immense potential to enhance the monitoring of patient safety and improve the use of medicines. The report offers policy considerations for countries and international partners in building PV capacity as an essential public function of a health system
