香港大学李嘉诚医学院、世界卫生组织传染病流行病学和控制合作中心Joseph T Wu研究组宣布他们对2019-nCoV爆发的国内外疫情进行了预测。相关论文发表在2020年1月31日出版的《柳叶刀》杂志上。

自2019年12月31日以来，中国武汉市报告了由2019新型冠状病毒（2019-nCoV）引起的非典型肺炎疫情。病例已扩散至中国其他城市以及其他国家，有可能引发全球疫情。研究组根据武汉向中国大陆以外城市扩散的病例数量，对武汉的疫情规模进行了估计，并预测了国内和全球流行病的公共卫生风险程度，同时考虑了社会和非药物预防干预措施。

研究组利用2019年12月31日至2020年1月28日武汉市国际扩散病例数（已知症状发生日为2019年12月25日至2020年1月19日）的数据，推断武汉市2019年12月1日至2020年1月25日的感染人数。然后对国内扩散病例进行估计。

研究组预测了2019-nCoV在全国和全球的传播，并考虑了武汉及周边城市从2020年1月23日至24日开始实施的大城市范围隔离的影响。采用易感-暴露-感染-恢复的集合种群模型模拟我国各大城市的疫情。

在研究组的基线预测中，截至2020年1月25日，预计武汉市2019-nCoV的基本繁殖数为2.68，流行倍增时间为6.4天。研究组还估计，在基线预测下，重庆、北京、上海、广州和深圳分别从武汉输入461例、113例、98例、111例和80例感染者。如果2019-nCoV在国内各地的传播率相似，随着时间的推移，研究组推断，中国多个主要城市的流行病已经呈指数增长，将滞后于武汉爆发约1-2周。

因为考虑到2019-nCoV已不仅在武汉范围内，所以中国其他主要城市也正在努力控制局部疫情。与中国交通联系密切的海外大城市也可能成为疫情爆发的中心，除非立即在人口和个人两个层面实施大规模的公共卫生干预措施。因为大量症状前病例扩散和缺乏大规模公共卫生干预措施，全球主要城市的独立自持爆发可能无法避免。研究组建议应在全球迅速部署备灾计划和缓解措施。

Title: Nowcasting and forecasting the potential domestic and international spread of the 2019-nCoV outbreak originating in Wuhan, China: a modelling study

Author: Joseph T Wu, Kathy Leung, Gabriel M Leung

Issue&Volume: January 31, 2020

Abstract: BackgroundSince Dec 31, 2019, the Chinese city of Wuhan has reported an outbreak of atypical pneumonia caused by the 2019 novel coronavirus (2019-nCoV). Cases have been exported to other Chinese cities, as well as internationally, threatening to trigger a global outbreak. Here, we provide an estimate of the size of the epidemic in Wuhan on the basis of the number of cases exported from Wuhan to cities outside mainland China and forecast the extent of the domestic and global public health risks of epidemics, accounting for social and non-pharmaceutical prevention interventions.MethodsWe used data from Dec 31, 2019, to Jan 28, 2020, on the number of cases exported from Wuhan internationally (known days of symptom onset from Dec 25, 2019, to Jan 19, 2020) to infer the number of infections in Wuhan from Dec 1, 2019, to Jan 25, 2020. Cases exported domestically were then estimated. We forecasted the national and global spread of 2019-nCoV, accounting for the effect of the metropolitan-wide quarantine of Wuhan and surrounding cities, which began Jan 23–24, 2020. We used data on monthly flight bookings from the Official Aviation Guide and data on human mobility across more than 300 prefecture-level cities in mainland China from the Tencent database. Data on confirmed cases were obtained from the reports published by the Chinese Center for Disease Control and Prevention. Serial interval estimates were based on previous studies of severe acute respiratory syndrome coronavirus (SARS-CoV). A susceptible-exposed-infectious-recovered metapopulation model was used to simulate the epidemics across all major cities in China. The basic reproductive number was estimated using Markov Chain Monte Carlo methods and presented using the resulting posterior mean and 95% credibile interval (CrI).FindingsIn our baseline scenario, we estimated that the basic reproductive number for 2019-nCoV was 2·68 (95% CrI 2·47–2·86) and that 75815 individuals (95% CrI 37304–130330) have been infected in Wuhan as of Jan 25, 2020. The epidemic doubling time was 6·4 days (95% CrI 5·8–7·1). We estimated that in the baseline scenario, Chongqing, Beijing, Shanghai, Guangzhou, and Shenzhen had imported 461 (95% CrI 227–805), 113 (57–193), 98 (49–168), 111 (56–191), and 80 (40–139) infections from Wuhan, respectively. If the transmissibility of 2019-nCoV were similar everywhere domestically and over time, we inferred that epidemics are already growing exponentially in multiple major cities of China with a lag time behind the Wuhan outbreak of about 1–2 weeks.InterpretationGiven that 2019-nCoV is no longer contained within Wuhan, other major Chinese cities are probably sustaining localised outbreaks. Large cities overseas with close transport links to China could also become outbreak epicentres, unless substantial public health interventions at both the population and personal levels are implemented immediately. Independent self-sustaining outbreaks in major cities globally could become inevitable because of substantial exportation of presymptomatic cases and in the absence of large-scale public health interventions. Preparedness plans and mitigation interventions should be readied for quick deployment globally.

DOI: 10.1016/S0140-6736(20)30260-9

Source: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30260-9/fulltext