The determinants of the risk of becoming infected by SARS-CoV-2, contracting COVID-19, and being affected by the more serious forms of the disease have been generally explored in merely qualitative terms. It seems reasonable to argue that the risk patterns for COVID-19 have to be usefully studied in quantitative terms too, whenever possible applying the same approach to the relationship 'dose of the exposure vs pathological response' commonly used for chemicals and already followed for several biological agents to SARS-CoV-2, too.

Using public transport systems has been reported to be a possible vector of virus transmission during epidemics. In this context, this article aims to analyze the spatial correlation between public transportation users and COVID-19 cases, using Recife (PE) as a case study. Using spatial analysis, the Moran I Global and Local index were calculated, and global and geographically weighted regression models were estimated for the months of March to June 2020, considering neighborhoods in Recife as a spatial unit of analysis.

An asymptomatic person infected with severe acute respiratory syndrome coronavirus 2 returned to Heilongjiang Province, China, after international travel. The traveler's neighbor became infected and generated a cluster of ≥71 cases, including cases in 2 hospitals. Genome sequences of the virus were distinct from viral genomes previously circulating in China. © 2020 Centers for Disease Control and Prevention (CDC). All rights reserved.

In Italy the Covid-19 emergency hit some of the territories crossed by the thickest commercial networks and the intense flows of human mobility The paper aims to reason on the factors of territorial vulnerability that may have facilitated the spread of the virus, trying to formulate a first hypothesis about the low density settlement structure has protected the more peripheral communities of the inner areas.

目的： 评估湖北新型冠状病毒肺炎的疫情输出风险及其他各省从湖北输入疫情的风险。 方法： 获取截至2020年2月14日我国各省报告病例数（不含临床诊断病例；不含中国香港、澳门和台湾数据）和百度迁徙指数，对各省累计报告病例数和湖北迁出指数进行相关分析，评估湖北疫情输出风险和其他省疫情输入风险。 结果： 全国累计报告确诊病例49 970例，其中湖北37 884例。湖北平均每天迁出至其他省的指数为312.09，武汉和湖北其他市分别为117.95和194.16。各省累计报告病例数与湖北、武汉及湖北其他市迁出至各省的人口迁徙指数均成正相关，相关系数分别为0.84、0.84和0.81；湖北、武汉及湖北其他市人口迁出分别可解释线性模型71.2%、70.1%和66.3%的变异。湖北高输出风险时间集中在1月27日前，其中1月23日前的疫情输出风险主要来源于武汉，之后主要来源于湖北其他市。疫情输入风险排前3位的是湖南、河南和广东，累计风险指数分别为58.61，54.75和49.62。 结论： 我国各省疫情主要由湖北输入引起，湖北限制人口流出、各省加强对湖北省迁入人员的检疫，可以较大程度降低各省（除湖北）疫情持续传播风险。

Objective To assess the imported risk of COVID-19 in Guangdong province and its cities, and conduct early warning. Methods Data of reported COVID-19 cases and Baidu Migration Index of 21 cities in Guangdong province and other provinces of China as of February 25, 2020 were collected. The imported risk index of each city in Guangdong province were calculated, and then correlation analysis was performed between reported cases and the imported risk index to identify lag time. Finally, we classified the early wanning levels of epidemic by imported risk index.

The characteristics of COVID-19, which is transmitted by contact and droplets and is infectious in the incubation period, were considered. Combined with the narrow space and airtight environment of the vehicle and based on SEIR model, the vehicle internal epidemic transmission model was established considering the factors of virus density, contact and infection rate among passengers, and travel time.

Passenger group in urban rail transit system under the COVID-19 epidemic was divided into susceptible, infected and exposed ones considering urban rail transit travel characters. In the research environment of COVID-19 free spread and the case sampling time of early spread, the infection probability of 0.41 was selected based on related studies. The urban rail transit ridership in COVID-19 case was divided into inbound/outbound phase and riding phase.

新型冠状病毒肺炎作为一种新发传染病，其流行过程具有一系列特殊影响因素和条件。本次疫情中，病原体“新”，使人产生“疑惑”；起病“缓”，给临床带来“迷惑”；传染源“杂”，给防控造成“困惑”；传播途径“易”，促使发病“剧增”；人群易感性“高”，引起“高发”；加之自然因素“复杂”和社会因素“叠加”，是本次疫情广泛传播流行的明显特征。我国采取的积极有效防控策略和措施极大改变了本次疫情的自然流行过程和轨迹，受到世界卫生组织专家组的高度肯定和众多国家和国际组织的赞扬。但认真总结，深入思考，从全局和长远谋划、实现中国乃至全球公共卫生安全将是今后一个相当长期的艰苦工作。.As a new infectious disease, the epidemic process of COVID-19 has a series of special influencing factors and conditions.

Objectives: For a large part of the coronavirus disease 2019 (COVID-19) pandemic, Singapore had managed to keep local cases in the single digits daily, with decisive measures. Yet, we saw this critical time point when the imported cases surged through our borders. The gaps which we can and have efficiently closed, using a public health approach and global border containment strategies, are aptly illustrated through this case.