Opinion: We know enough now to act decisively against Covid-19. Social distancing is a good place to start
In a recent and controversial First Opinion, epidemiologist and statistician John Ioannidis argues that we lack good data on many aspects of the Covid-19 epidemic, and seems to suggest that we should not take drastic actions to curtail the spread of the virus until the data are more certain.
He is absolutely right on the first point. The U.S. has done fewer tests per capita so far than almost any rich country in the world. And many critical details of the epidemiology — including the absolute number of cases, the role of children in transmission, the role of presymptomatic transmission, and the risk of dying from infection with SARS-CoV-2 — remain uncertain.
