Pandemics share three features. They are almost always unexpected, suddenly emerging in one place then spreading around the world. As well as causing serious illness and death, pandemics are responsible for social disruption and substantial economic loss. Finally, governments are usually unprepared to deal with pandemics. The recent Covid-19 pandemic is testimony to the confusion and blunders that characterised the responses in many countries. Other than these commonalities, pandemics differ in almost all their main characteristics, particularly where they come from, why they spread and how they end (if they do end) [1, 2].