ABSTRACT
ObjectiveSchool reopening has not yet started in China where the COVID-19 outbreak has reached ending stage, largely due to a great concern about COVID-19 infections on students. We attempted to quantitatively evaluate the risk of COVID-19 infections on students caused by school reopening. Study designWe collected the data of the numbers of teachers, population size and newly confirmed COVID-19 cases in the past 14 days in typical provinces/cities of China, and then analyzed the risk of COVID-19 infections in schools with respect to each province/city. MethodsA step-by-step procedure was explored to calculate the probability of COVID-19 infections on students as transmitted from infected teachers. Two critical assumptions for analysis were proposed: (i) only locally generated cases were counted while imported cases were omitted; (ii) the secondary attack rate of the COVID-19 virus in schools is similar to that in households in China, ranging from 3-10%. ResultsThe probability of COVID-19 resurgence within one week on students of primary, middle and high schools in China (outside Hubei) is extremely low (<0.2%) in each province/city, and such probability can be updated daily and weekly based on the newly confirmed cases in the past 14 days. In some areas without newly confirmed cases in the past 14 days, the risk is zero. ConclusionsOur work provides guidance for local governments to make risk level-based policies for school reopening. Currently, the risk of COVID-19 infections on students is extremely low in China (outside Hubei) and therefore school reopening can be initiated without the endanger of infections on students.
ABSTRACT
An ongoing outbreak of atypical pneumonia caused by the 2019 novel coronavirus (SARS-CoV-2) is hitting Wuhan City and has spread to other provinces/cities of China and overseas. It very urgent to forecast the future course of the outbreak. Here, we provide an estimate of the potential total number of confirmed cases in mainland China by applying Boltzmann-function based regression analyses. We found that the cumulative number of confirmed cases from Jan 21 to Feb 14, 2020 for mainland China, Hubei Province, Wuhan City and other provinces were all well fitted with the Boltzmann function (R2 being close to 0.999). The potential total number of confirmed cases in the above geographic regions were estimated at 95% confidence interval (CI) as 79589 (71576, 93855), 64817 (58223, 77895), 46562 (40812, 57678) and 13956 (12748, 16092), respectively. Notably, our results suggest that the number of daily new confirmed cases of SARS-CoV-2 in mainland China (including Hubei Province) will become minimal between Feb 28 and Mar 10, 2020, with 95% CI. In addition, we found that the data of cumulative confirmed cases of 2003 SARS-CoV in China and Worldwide were also well fitted to the Boltzmann function. To our knowledge this is the first study revealing that the Boltzmann function is suitable to simulate epidemics. The estimated potential total number of confirmed cases and key dates for the SARS-CoV-2 outbreak may provide certain guidance for governments, organizations and citizens to optimize preparedness and response efforts.