An international comparison of the second derivative of COVID-19 deaths after implementation of social distancing measures

This work compares deaths for confirmed COVID-19 cases in China to eight other countries, Italy, Spain, France, USA, UK, Germany, Netherlands and South Korea. After implementing varying intensities and timing of social distancing measures, several appear to be converging onto the decline in the daily growth rate of deaths, or relative second derivative of total deaths, seen in China after the implementation an aggressive social distancing policy. By calculating future trajectories in these countries based on the observed Chinese fatality statistics, an estimate of the total deaths and maximum daily death rates over a defined period of time is made. Our lower bound estimate for the United Kingdom based on the real data approximates the lower bound estimate of the recent modelling study of Ferguson et al. [1]. These results suggest there may be a threshold of effective public health intervention. Our method of viewing the data may be helpful in monitoring the course of the epidemic, judging the effectiveness of implementation, and monitoring the relaxation of social distancing.