2023 年 46 巻 4 号 p. 3-8
The COVID-19 pandemic has had a huge impact on the world for three and half years, since the end of 2019. A nasty feature of the disease is the existence of numerous (infected) cases without symptoms. It was difficult for society to engage in social/economic activities while avoiding spreading of the disease. The internet played an indispensable role in the fight against the pandemic in many ways. In particular numerous public health date, which one would have never imagined if it were not for the pandemic, were made open to the public through the Internet. In this paper, we discuss a few issues concerning the usage of these open data in policy-making. We consider the following four topics regarding COVID-19: (1) incubation time, (2) the effect of vaccination, (3) estimation of the ratio between actual cases and cases reported by health authorities, and (4) estimation of excessive deaths during the pandemic.