  The outbreak of novel coronavirus-caused pneumonia (COVID-19) in Wuhan has
attracted worldwide attention. Here, we propose a generalized SEIR model to
analyze this epidemic. Based on the public data of National Health Commission
of China from Jan. 20th to Feb. 9th, 2020, we reliably estimate key epidemic
parameters and make predictions on the inflection point and possible ending
time for 5 different regions. According to optimistic estimation, the epidemics
in Beijing and Shanghai will end soon within two weeks, while for most part of
China, including the majority of cities in Hubei province, the success of
anti-epidemic will be no later than the middle of March. The situation in Wuhan
is still very severe, at least based on public data until Feb. 15th. We expect
it will end up at the beginning of April. Moreover, by inverse inference, we
find the outbreak of COVID-19 in Mainland, Hubei province and Wuhan all can be
dated back to the end of December 2019, and the doubling time is around two
days at the early stage.
