The Impact of Polycrisis on Healthcare Systems-Analyzing Challenges and the Role of Social Epidemiology.

In response to contemporary challenges such as the COVID-19 pandemic, climate change, armed conflicts, and economic instability, healthcare systems worldwide are increasingly confronted with multifaceted and overlapping crises-collectively referred to as polycrisis. These interconnected threats amplify one another, placing unprecedented strain on healthcare infrastructure, governance, and equity. The COVID-19 pandemic alone led to an estimated 16.3 million missed hospitalizations in 2020 and 14.7 million in 2021, revealing systemic vulnerabilities and deepening social inequalities. Armed conflicts, such as in Syria and Gaza, have devastated healthcare access. In Gaza, by mid-2024, 85% of the population had been forcibly displaced, with only 17 of 36 hospitals partially functioning and over 885 healthcare workers killed. Climate change further exacerbates health burdens, with over 86% of urban residents globally exposed to harmful air pollution, contributing to 1.8 million deaths annually. This study introduces a novel perspective by applying social epidemiology to the analysis of polycrisis. While the existing literature often emphasizes political or economic dimensions, our approach highlights how overlapping crises affect population health, social vulnerability, and systemic resilience. By integrating sociodemographic and environmental data, social epidemiology supports crisis-resilient care models, targeted interventions, and equitable health policies. We argue for a stronger mandate to invest in data infrastructure, enhance surveillance, and embed social determinants into health system responses.