COVID-19: What Do We Have Learnt So Far?

Coronaviruses (CoVs) are the largest group of viruses; order is Nidovirales while family is Coronaviridae. They are further subdivided into four groups, the alpha, beta, gamma and delta coronaviruses [1]. These viruses usually cause mild infections but two zoonotic epidemics of the betacoronaviruses, severe acute respiratory syndrome coronavirus (SARS-CoV) [2] and Middle East respiratory syndrome coronavirus (MERS-CoV) [3] have occurred in this century, mortality rates of 10% for SARS-CoV [4] while a very high i.e. 37% for MERS-CoV [5].