How to Estimate Accurate Numbers of All the Patients with COVID-19
The fact that patients with severe symptoms have to go to hospital leads to the accurate number of confirmed severe cases. It is possible to figure out the number of all the patients with Covid-19 if we can establish a standard ratio of severe cases, because the ratio of confirmed severe cases should be consistent with the standard ratio.
One available standard ratio of severe cases is 3.4% which was obtained during a close contact tracing . Because there were no missing patients including the asymptomatic in the contact tracing, its ratio of severe cases should serve as a standard one.
A nation, for instance, has 10,000 confirmed cases at present and 51% of them are severe cases. Then the real number of all patients is estimated to be 10,000 * (51% / 3.4%) = 10,000 *15 = 150,000.
This method can be used for a real-time surveillance, providing accurate information about how many people have been infected in any nation.
1. Bi Q, Wu Y, Mei S, Ye C, Zou X, Zhang Z, et al. Epidemiology and Transmission of COVID-19 in Shenzhen China: Analysis of 391 cases and 1,286 of their close contacts. MedRxiv. 2020.