Simple Estimates of the Number of New COVID-19 Infections by Date of Onset using Open Data
2023 Volume 42 Pages 71-78
Details
2023 Volume 42 Pages 71-78
We propose a simple method for estimating the number of new COVID-19 cases by date of onset from the number of new COVID-19 cases by date of publication. We use open data including the “date of onset” and “date of publication” of the Tokyo Metropolitan Government. This method has about one-third day-of-week effect of that based on the published date. This method is effective as a method of seasonal adjustment for new COVID-19 infections.
The data for Tokyo only exist for October 1, 2020 and later. So we used open data for Hokkaido, Miyagi, Hyogo, and Okinawa prefectures for earlier estimates. The problems of runout due to the small sample size and the shift in the peak period due to regional differences remain as issues to be addressed.
In the sixth wave, there is an expansion in the difference in the elapsed time from the date of establishment to the date of publication due to the presence or absence of the onset date. It is not observed in the period from the third to fifth waves. It remains to be examined whether the proposed method requires correction for the sixth wave.
