SARS-CoV-2 is the recently discovered virus which has resulted in the pandemic illness known as coronavirus disease 2019 (COVID-19) [1]. It is from the family of viruses known as Coronaviridae, which were also responsible for severe acute respiratory syndrome (SARS), which originated in China in 2002, and Middle East respiratory syndrome coronavirus in 2012. It is thought to be a zoonosis, possibly originating in bats, which has undergone intra-species transfer between intermediary hosts and humans.

The high infectivity of SARS-Cov-2 is a major contributor to this pandemic. Infectivity of a pathogen can be quantified as the basic reproduction number (R0). This is the number of cases directly generated by one case in a population where all individuals are susceptible to infection [2]. Estimates suggest that, for SARS-CoV-2, R0 is >2.4 [3,4,5]; thus for every case which occurs, on average more than two additional cases are generated in a susceptible population, in the absence of adequate measures such as isolation. For comparison, seasonal flu has an R0 of ~1.2 [6].

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