Spatially Explicit Modeling of 2019-nCoV Epidemic Trend based on Mobile Phone Data in Mainland China

Xiaolin Zhu; Aiyin Zhang; Shuai Xu; Pengfei Jia; Xiaoyue Tan; Jiaqi Tian; Tao Wei; Zhenxian Quan; Jiali Yu

Wuhan, a large city with 14 million residents and a major air and train transportation hub of central China, identified a cluster of unexplained cases of pneumonia on December 29, 2019 1 . Four patients were initially reported and all these initial cases were linked to the Huanan Seafood Wholesale Market 2 . Chinese health authorities and scientists did immediate investigation and isolated a novel coronavirus from these patients by January 7, 2020, which is then named as 2019-nCoV by the World Health Organization 3, 4 . 2019-nCoV can cause acute respiratory diseases that progress to severe pneumonia 5 . The infection fatality risk is around 3% estimated from the data of early outbreak 3, 6 . Information on new cases strongly indicates human-to-human spread 1, 7, 8 . Infection of 2019-nCoV quickly spread to other cities in China and other countries ( Figure 1 ). It becomes an event of global health concern 9 . Up to February 11, 2020, according to the reports published by the Chinese Center for Disease Control and Prevention, all prefecturelevel cities of mainland China have confirmed cases and the total number reaches to 42667, of whom 1016 have died and 4242 recovered; 24 oversea countries have 398 confirmed cases (1 died). Chinese government took great effort to control the spread of disease, including closing the public transportation from and to Wuhan on January 23, extending the Spring Festival holiday, postponing the school-back day, and suspending all domestic and international group tours. Unfortunately, many external factors bring a challenge to control virus spreading. First, it might be already late to stop the migration of infected cases. Evidence suggests that Wuhan is the center of 2019-nCoV outbreak 1, 10 . However, around 5 million Wuhan residents left Wuhan in January 2020 due to the Spring Festival (January 24, 2020). It is very likely that a considerable number of infected cases have moved from Wuhan to other cities before Wuhan government implemented border control on January 23. Second, it is highly possible that infected cases spread the virus to their family members or relatives 7 . A study based on 425 patients at the early stage of outbreak revealed that the time from infection to illness onset is 5.2 days 1 . As a result, presymptomatic cases who have left Wuhan may not be isolated themselves from their family and relatives 11 . Third, due to the sudden outbreak of virus, the preparation and resources for preventing virus transmission are limited. The protective equipment in many hospitals in Wuhan was in short supply so that it is difficult to maintain strict personal hygiene. With the quick increase of infected cases, Wuhan and other cities in Hubei Province have large pressure to isolate and give medical treatment to infected people. All above factors make preventing the spread of 2019-nCoV even more difficult than the severe acute respiratory syndrome (SARS), another coronavirus outbreak in China 17 years ago that caused more than 8000 infections and 800 deaths.