key: cord-0004694-rftsq2gd authors: Zhang, Sheng; Diao, Meng Yuan; Duan, Liwei; Lin, Zhaofen; Chen, Dechang title: The novel coronavirus (SARS-CoV-2) infections in China: prevention, control and challenges date: 2020-03-02 journal: Intensive Care Med DOI: 10.1007/s00134-020-05977-9 sha: 6e66b2e700ec62210c17a46e27451004c8354363 doc_id: 4694 cord_uid: rftsq2gd nan than 30,000 members from military and public hospitals have successively headed out to Wuhan and other cities in Hubei Province. Although the number of confirmed cases is still increasing, the increasing rate has showed a downward trend from February 4, 2020 (eFigure 2). Despite Hubei Province, Guangdong, Henan, Zhejiang, Hunan and Anhui are the top five provinces with respect to the ranking order of confirmed cases. The increasing rates of confirmed cases in these provinces also showed a downward trend recently (eFigure 3). Using a real-time Bayesian estimation model and a reported serial interval of COVID-19 [3, 4] , we computed time-dependent reproduction number, R(t), which is defined as the expected number of secondary cases that one primary case will generate during infectious disease transmission. As shown in Fig. 1 , R(t) has showed a downward trend in Wuhan, Hubei Province, outside Hubei, and China from January 27, 2020, to February 10, 2020. The downward trend of R(t) indicates that the prevention and control measures may be effective, although long-term effects remain to be evaluated. However, we still confront a number of great challenges. First, source of SARS-CoV-2 remains pendent and the population is generally susceptible to the new virus. Second, although human-to-human spread [3] is thought to occur mainly via respiratory droplets and close contact, fecal-oral transmission or vertical transmission may also be a means of transmission. Third, asymptomatic cases with COVID-19 have been reported [5] , and several places in China have reported confirmed cases without clear transmission chain, which indicates that there may be some infected cases still wandering among population and spreading virus. Fourth, as the Spring Festival The estimates of R(t) were truncated at February 10, 2020, because the diagnosis criteria for COVID-19 are adjusted since February 12, giving a sharp increase in number of new cases who was identified as having COVID-19. Incorporating these data for R(t) derivation would obtain misleading results submitted. All authors commented on previous versions of the manuscript and read and approved the final manuscript. 2/4a1b1 ec6c0 35480 99de1 c3aa9 35d04 fd.shtml 2. World Health Organization (2020) Coronavirus disease (COVID-19) Situation Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia Real time Bayesian estimation of the epidemic potential of emerging infectious diseases Transmission of 2019-nCoV infection from an asymptomatic contact in Germany The authors declared no conflict of interest. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.Accepted: 19 February 2020