"Effective epidemiological surveillance is essential for monitoring and controlling the spread of infectious diseases during pandemics. The COVID-19 pandemic has highlighted the importance of timely and accurate surveillance, and the need for real-time data sharing to inform public health decision-making. This article provides an overview of epidemiological surveillance in pandemics, including the key principles, methods, and technologies used to collect, analyze, and disseminate data. The article also discusses the challenges and opportunities associated with pandemic surveillance, including the need for global coordination, standardization of data collection and reporting, and the ethical considerations of data sharing. By understanding the principles and challenges of epidemiological surveillance in pandemics, public health officials and policymakers can develop effective strategies to detect, prevent, and control the spread of infectious diseases."