Modern cities are reservoirs of infectious diseases: urbanization is a catalyst for pathogen emergence

Urbanization has significantly transformed demographic patterns worldwide, with the global urban population rising from just 20% in high-income countries and 5% in low- and middle-income countries a little more than a century ago to a projected 68% of 9.8 billion people by 2050, primarily driven by growth in Asia and Africa. While urban areas can spur economic growth and innovation, they also create conditions conducive to the rapid transmission of infectious diseases due to high population density, mobility, and ecological disruption. Historical pandemics have identified cities as epicentres of disease outbreaks, recently exemplified by COVID-19, which underscored the vulnerabilities associated with urban living. Addressing these multisectoral issues requires integrated surveillance systems, enhanced healthcare infrastructure, and coordinated efforts in wastewater management and vector control. Sustainably transforming cities from amplifiers of disease into pathogen-resilient environments necessitates proactive, collaborative strategies across disciplines to safeguard public health against evolving global health threats. In highlighting a ‘wicked problem’ with deep social and economic roots that make it resistant to easy fixes, this lead article calls for coordinated transdisciplinary research to find effective, affordable, and long-lasting solutions.