Fig. 1

Types of infected cases and the fatality rate (FR). A Schema of different types of cases and deaths in relation to their testing and death time. At the time of reporting detected cases, the number of undetected cases is estimated using Eq. (2) (see “Methods”). \(FR_{d}\) is the FR among detected cases, and \(FR_{ud}\) is the FR among undetected cases. Reported cases include both detected and late-detected cases (after undetected deaths are tested and confirmed), while total cases include both detected and undetected cases. B Time-varying FRs among reported and total cases. The solid red line represents the proportion of reported deaths (i.e., detected and undetected deaths) among the total reported cases. The solid blue line represents the proportion of reported deaths among the total cases. The dashed red line represents the average FR among the reported cases (5.3%), whereas the blue dashed line shows the average FR among the total cases (4.7%). Note that the FR of the total cases was higher than that of the reported cases in the first few days because \(FR_{ud}\) was assumed to be same as the mean \(FR_{d}\) between May 11 and May 26. Data points during the earliest dates when the number of detected or undetected cases was zero are not shown