Multi-scale characteristics of contagion and systematic prevention and control of its infection —analysis of COVID-19 epidemic

Interactions between system components and complexity profile were analyzed from the perspective of complex system science to reveal the complexity and multiscale characteristics of infectious disease outbreak．The multiscale law of requisite variety was applied to explore systematic preventive measures at individuals to communities levels．The mutual assistance of individuals, communities and countries are suggested to be most helpful to build an effective mitigation effort to the global COVID-19 pandemic．