Introduction
Everybody knows that pestilences have a way of recurring in the world; yet somehow we find it hard to believe in ones that crash down on our heads from a blue sky.—Albert Camus, The Plague, 1948.
COVID-19 is currently a global pandemic. A pandemic is a disease outbreak that is prevalent over a wide area, from a group of countries to the entire world. The current pandemic disease, COVID-19, is caused by a novel coronavirus, SARS-CoV-2. The global spread is following an approximately exponential curve: it took 67 days to reach the first 100,000 cases; 11 more days to reach 200,000; and just 4 more to reach 300,000 cases. This virus’s deadliness lies in its stealth, spreading silently with an incubation period of weeks. It kills slowly, weeks after infection (Chen et al., Ferguson et al.).