Novel indicator of change in COVID-19 spread status

In the fight against the pandemic of COVID-19, it is important to be quick to detect changes in the rate of spread and to be precise to predict the future. We have succeeded in formulating a new indicator based on daily number of infected people from publicly available data, which enables us to do the both. We show the validity of the indicator by demonstrating that a universal analysis of current status of COVID-19 spreading over countries can predict effects of measures such as the blockage of cities and social distancing, signs of new spread, and possible regional dependence in the formation of herd immunity.