While Covid-19 is different in many ways from the Spanish flu – particularly in terms of who it affects and its mortality rate so far – there is a very important lesson about the difference social distancing can make. It might still be one of the best ways of fighting this pandemic.
…
Each person infected with the Covid-19 coronavirus is thought to pass it on to an average of 2-3 other people in the early stages of an outbreak. This contagiousness is measured by epidemiologists using something known as a “reproduction number”.
…
Rhinovirus, which is one of those that causes the common cold, has a reproduction number of 1.2-1.83. Most estimates for Covid-19 have put its reproduction number at between 1.4-3.9.
…
There is already some evidence that staying at home, and maintaining a safe distance from others, can slow the spread and stop this domino effect. Research looking at infections in Wuhan showed that the introduction of large-scale control measures saw the reproduction number in the city fall from 2.35 to almost one. When a reproduction number reaches one, the number of cases will stop rising as effectively each infected person is passing it on to just one other person.
