The outbreak of COVID-19 has rapidly become a global pandemic. It seriously challenges each country and government for its capacity and management of public health systems facing emergency. No single country can be an island that is immune to this pandemic, regardless of its geographic location, population profile, or status of economic development. What matters most to a country is the actions taken by the government to minimize the negative impacts of the whole society. Countries with different social structures, lifestyles and culture backgrounds tend to adopt different policies to contain the spread of COVID-19. Taking active control strategies to halt the spread of this pandemic at an affordable cost becomes imperative to every society and country.

In this issue, our Managing Editor, Professor Baoding Liu of Tsinghua University, kindly assembles five novel studies on modeling COVID-19 from the perspective of uncertainty theory for our readers and the research community. FODM certainly appreciates Professor Liu’s special efforts.