Juanjuan Zhang1, Maria Litvinova2, Wei Wang1, Yan Wang1, Xiaowei Deng1, Xinghui Chen1, Mei Li1, Wen Zheng1, Lan Yi1, Xinhua Chen1, Qianhui Wu1, Yuxia Liang1, Xiling Wang1, Juan Yang1, Kaiyuan Sun3, Ira M Longini4, M Elizabeth Halloran5,6, Peng Wu7, Benjamin J Cowling7, Stefano Merler8, Cecile Viboud3, Alessandro Vespignani9,2, Marco Ajelli8, Hongjie Yu1. 1. School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China. 2. ISI Foundation, Turin, Italy. 3. Division of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, MD, USA. 4. Department of Biostatistics, College of Public Health, Health Professions, and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA. 5. Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. 6. Department of Biostatistics, University of Washington, Seattle, WA, USA. 7. WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong Special Administrative Region, China. 8. Bruno Kessler Foundation, Trento, Italy. 9. Laboratory for the Modeling of Biological and Socio-technical Systems, Northeastern University, Boston, MA USA.
Abstract
BACKGROUND: The COVID-19 epidemic originated in Wuhan City of Hubei Province in December 2019 and has spread throughout China. Understanding the fast evolving epidemiology and transmission dynamics of the outbreak beyond Hubei would provide timely information to guide intervention policy. METHODS: We collected individual information on 8,579 laboratory-confirmed cases from official publically sources reported outside Hubei in mainland China, as of February 17, 2020. We estimated the temporal variation of the demographic characteristics of cases and key time-to-event intervals. We used a Bayesian approach to estimate the dynamics of the net reproduction number (Rt) at the provincial level. RESULTS: The median age of the cases was 44 years, with an increasing of cases in younger age groups and the elderly as the epidemic progressed. The delay from symptom onset to hospital admission decreased from 4.4 days (95%CI: 0.0-14.0) until January 27 to 2.6 days (0.0-9.0) from January 28 to February 17. The mean incubation period was estimated at 5.2 days (1.8-12.4) and the mean serial interval at 5.1 days (1.3-11.6). The epidemic dynamics in provinces outside Hubei was highly variable, but consistently included a mix of case importations and local transmission. We estimate that the epidemic was self-sustained for less than three weeks with Rt reaching peaks between 1.40 (1.04-1.85) in Shenzhen City of Guangdong Province and 2.17 (1.69-2.76) in Shandong Province. In all the analyzed locations (n=10) Rt was estimated to be below the epidemic threshold since the end of January. CONCLUSION: Our findings suggest that the strict containment measures and movement restrictions in place may contribute to the interruption of local COVID-19 transmission outside Hubei Province. The shorter serial interval estimated here implies that transmissibility is not as high as initial estimates suggested.
BACKGROUND: The COVID-19 epidemic originated in Wuhan City of Hubei Province in December 2019 and has spread throughout China. Understanding the fast evolving epidemiology and transmission dynamics of the outbreak beyond Hubei would provide timely information to guide intervention policy. METHODS: We collected individual information on 8,579 laboratory-confirmed cases from official publically sources reported outside Hubei in mainland China, as of February 17, 2020. We estimated the temporal variation of the demographic characteristics of cases and key time-to-event intervals. We used a Bayesian approach to estimate the dynamics of the net reproduction number (Rt) at the provincial level. RESULTS: The median age of the cases was 44 years, with an increasing of cases in younger age groups and the elderly as the epidemic progressed. The delay from symptom onset to hospital admission decreased from 4.4 days (95%CI: 0.0-14.0) until January 27 to 2.6 days (0.0-9.0) from January 28 to February 17. The mean incubation period was estimated at 5.2 days (1.8-12.4) and the mean serial interval at 5.1 days (1.3-11.6). The epidemic dynamics in provinces outside Hubei was highly variable, but consistently included a mix of case importations and local transmission. We estimate that the epidemic was self-sustained for less than three weeks with Rt reaching peaks between 1.40 (1.04-1.85) in Shenzhen City of Guangdong Province and 2.17 (1.69-2.76) in Shandong Province. In all the analyzed locations (n=10) Rt was estimated to be below the epidemic threshold since the end of January. CONCLUSION: Our findings suggest that the strict containment measures and movement restrictions in place may contribute to the interruption of local COVID-19 transmission outside Hubei Province. The shorter serial interval estimated here implies that transmissibility is not as high as initial estimates suggested.
Authors: Qun Li; Xuhua Guan; Peng Wu; Xiaoye Wang; Lei Zhou; Yeqing Tong; Ruiqi Ren; Kathy S M Leung; Eric H Y Lau; Jessica Y Wong; Xuesen Xing; Nijuan Xiang; Yang Wu; Chao Li; Qi Chen; Dan Li; Tian Liu; Jing Zhao; Man Liu; Wenxiao Tu; Chuding Chen; Lianmei Jin; Rui Yang; Qi Wang; Suhua Zhou; Rui Wang; Hui Liu; Yinbo Luo; Yuan Liu; Ge Shao; Huan Li; Zhongfa Tao; Yang Yang; Zhiqiang Deng; Boxi Liu; Zhitao Ma; Yanping Zhang; Guoqing Shi; Tommy T Y Lam; Joseph T Wu; George F Gao; Benjamin J Cowling; Bo Yang; Gabriel M Leung; Zijian Feng Journal: N Engl J Med Date: 2020-01-29 Impact factor: 176.079
Authors: Peng Wu; Xinxin Hao; Eric H Y Lau; Jessica Y Wong; Kathy S M Leung; Joseph T Wu; Benjamin J Cowling; Gabriel M Leung Journal: Euro Surveill Date: 2020-01
Authors: Bruce Aylward; Philippe Barboza; Luke Bawo; Eric Bertherat; Pepe Bilivogui; Isobel Blake; Rick Brennan; Sylvie Briand; Jethro Magwati Chakauya; Kennedy Chitala; Roland M Conteh; Anne Cori; Alice Croisier; Jean-Marie Dangou; Boubacar Diallo; Christl A Donnelly; Christopher Dye; Tim Eckmanns; Neil M Ferguson; Pierre Formenty; Caroline Fuhrer; Keiji Fukuda; Tini Garske; Alex Gasasira; Stephen Gbanyan; Peter Graaff; Emmanuel Heleze; Amara Jambai; Thibaut Jombart; Francis Kasolo; Albert Mbule Kadiobo; Sakoba Keita; Daniel Kertesz; Moussa Koné; Chris Lane; Jered Markoff; Moses Massaquoi; Harriet Mills; John Mike Mulba; Emmanuel Musa; Joel Myhre; Abdusalam Nasidi; Eric Nilles; Pierre Nouvellet; Deo Nshimirimana; Isabelle Nuttall; Tolbert Nyenswah; Olushayo Olu; Scott Pendergast; William Perea; Jonathan Polonsky; Steven Riley; Olivier Ronveaux; Keita Sakoba; Ravi Santhana Gopala Krishnan; Mikiko Senga; Faisal Shuaib; Maria D Van Kerkhove; Rui Vaz; Niluka Wijekoon Kannangarage; Zabulon Yoti Journal: N Engl J Med Date: 2014-09-22 Impact factor: 91.245