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Mass testing—An underexplored strategy for COVID-19 control

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The Innovation 2021年第2期2卷 137-138页

作者： Mingwang Shen yanni xiao Guihua Zhuang Yan Li Lei Zhang China-Australia Joint Research Center for Infectious Diseases School of Public HealthXi’an Jiaotong University Health Science CenterXi’an 710061China School of Mathematics and Statistics Xi’an Jiaotong UniversityXi’an 710049China Department of Population Health Science and Policy Icahn School of Medicine at Mount SinaiNew YorkNY 10029USA Department of Obstetrics Gynecologyand Reproductive ScienceIcahn School of Medicine at Mount SinaiNew YorkNY 10029USA Melbourne Sexual Health Centre Alfred HealthMelbourneVICAustralia Central Clinical School Faculty of MedicineNursing and Health SciencesMonash UniversityMelbourneVICAustralia Department of Epidemiology and Biostatistics College of Public HealthZhengzhou UniversityZhengzhou 450001China

Mass testing is an intervention strategy for COVID-19 control in the general population regardless of the presentation of *** involves collecting nasal or pharyngeal swabs for DNA testing,often using the polymerase chain reaction *** that have used mass testing consider it to be a viable strategy to control the COVID-19 pandemic as the strategy can potentially identify and isolate asymptomatic cases in the early stages of infection and reduce the risk of virus *** the reopening of Wuhan,China,in early April 2020,China has conducted mass testings in three megacities with populations of over 10 million,including Beijing and Qingdao1 at the beginning of their local outbreaks,and Wuhan immediately after the reopening.

关键词： testing strategy Wuhan

Analysis of a SIS epidemic model with stage structure and a delay

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Communications in Nonlinear Science and Numerical Simulation 2001年第1期6卷 35-39页

作者： yanni xiao and Lansun CHEN (Academy of Mathematics & System Sciences, Academic Sinica, Beijing 100080, China ) Academy of Mathematics & System Sciences Academia Sinica Beijing 100080 China

A disease transmission model of SIS type with Stage structure and a delay corresponding to the infectious period is formulated. By constructing the difference operator and using global convergence theorem, we show that the disease-free equilibrium is globally asymp- totically stable. The Stability of an endemic equilibrium are investigated for the differential- difference equations.

关键词： SIS epidemic model delay threshold globally asymptotically stable

Quantifying competitive advantages of mutant strains in a population involving importation and mass vaccination rollout

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Infectious Disease Modelling 2021年第1期6卷 988-996页

作者： Fan Xia Xinpei Yang Robert A.Cheke yanni xiao School of Mathematics and Statistics Xi'an Jiaotong UniversityXi'an710049China School of Mathematics and Statistics Shaanxi Normal UniversityXi'an710119China Natural Resources Institute University of Greenwich at MedwayCentral AvenueChatham MaritimeKentME44BUK

The SARS-CoV-2 Delta variant,known as B.1.617.2 and first identified in India,is becoming a dominant strain in many countries due to its extreme *** and quantifying the transmissibility and competitive advantage of the Delta variant is of major significance for countries around the world so that appropriate measures to mitigate and even eliminate the epidemic can be *** at such problems,we proposed a method to model the invasion process of a novel strain and estimate the competitive advantage of the invading strain over the local *** applied this method to study the invasion and spread of the Delta variant into *** have estimated the basic reproduction number of the Delta variant as being 49%higher than that of the Alpha variant(CI:45-52%),assuming a mean generation interval of 5 days with a standard deviation of 3 *** the period 11 April to 17 May 2021,the effective reproduction number of the Delta variant was 65%higher than that of the Alpha variant in England(CI:61-70%).Our results show that the Delta variant has a significantly higher transmission capacity than other strains,which explains the rebound of the epidemic in many countries,even in those with relatively high vaccination coverages.

关键词： COVID-19 SARS-CoV-2 Delta variant Competitive advantage Reproduction number

MODELING STRATEGIES FOR CONTROLLING H1N1 OUTBREAKS IN CHINA

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International Journal of Biomathematics 2012年第4期5卷 63-81页

作者： JIN ZHANG yanni xiao Department of Applied Mathematics Xi'an Jiaotong University Xi'an 710049 P. R. China

There has been a global attack of A/H1N1 virus in 2009, which widely affected the world＇s normal stability and economic development. Since the emergence of the first diagnosed A/H1N1 influenza infected person in 11 May 2009 in China, very strict policy including quarantine and isolation measures were widely implemented to control the spread of this disease before the vaccine appeared. We propose a compartmental model that mimics the infection process of A/H1N1 under control strategies taken in China's Mainland. Apart from theoretical analysis, using the statistic data of Shaanxi Province, we estimated the unknown epidemiological parameters of this disease in Shaanxi via least-squares fitting method. The estimated control reproductive number of H1N1 for its first peak was Rc1 = 2.555 （95% CI： 2.362 2.748） and that for the second peak was Rc2 = 1.886 （95% CI： 1.765-2.001）. Our findings in this paper suggest that neither quarantine nor isolation measures could be relaxed, and the implementation of these interventions can reduce the pandemic outbreak of A/H1N1 pandemic significantly.

关键词： A/HIN1 influenza quarantine isolation least-squares fitting.

An updated estimation of the risk of transmission of the novel coronavirus(2019-nCov)

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Infectious Disease Modelling 2020年第1期5卷 248-255页

作者： Biao Tang Nicola Luigi Bragazzi Qian Li Sanyi Tang yanni xiao Jianhong Wu The Interdisplinary Research Center for Mathematics and Life Sciences Xi’an Jiaotong UniversityXi’an710049People’s Republic of China Laboratory for Industrial and Applied Mathematics Department of Mathematics and StatisticsYork UniversityTorontoOntarioM3J 1P3Canada School of Mathematics and Statistics Xi’an Jiaotong UniversityXi’an710049People’s Republic of China School of Mathematics and Information Science Shaanxi Normal UniversityXi’an710119People’s Republic of China Fields-CQAM Laboratory of Mathematics for Public Health York UniversityTorontoOntarioM3J 1P3Canada

The basic reproduction number of an infectious agent is the average number of infections one case can generate over the course of the infectious period,in a naïve,uninfected *** is well-known that the estimation of this number may vary due to several methodological issues,including different assumptions and choice of parameters,utilized models,used datasets and estimation *** the spreading of the novel coronavirus(2019-nCoV)infection,the reproduction number has been found to vary,reflecting the dynamics of transmission of the coronavirus outbreak as well as the case reporting *** to significant variations in the control strategies,which have been changing over time,and thanks to the introduction of detection technologies that have been rapidly improved,enabling to shorten the time from infection/symptoms onset to diagnosis,leading to faster confirmation of the new coronavirus cases,our previous estimations on the transmission risk of the 2019-nCoV need to be *** using time-dependent contact and diagnose rates,we refit our previously proposed dynamics transmission model to the data available until January 29th,2020 and re-estimated the effective daily reproduction ratio that better quantifies the evolution of the *** estimated when the effective daily reproduction ratio has fallen below 1 and when the epidemics will *** updated findings suggest that the best measure is persistent and strict *** epidemics will continue to grow,and can peak soon with the peak time depending highly on the public health interventions practically implemented.

关键词： Novel coronavirus Emerging and reemerging pathogens Mathematical modeling Basic reproduction number Effective daily reproduction ratio

THE DYNAMICS OF A DISCRETE SEIT MODEL WITH AGE AND INFECTION AGE STRUCTURES

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International Journal of Biomathematics 2012年第3期5卷 61-76页

作者： HUI CAO yanni xiao YICANG ZHOU Department of Applied Mathematics Xi' an Jiaotong University Xi'an Shaanxi 710049 P. R. China

Age and infection age have significant influence on the transmission of infectious dis- eases, such as HIV/AIDS and TB. A discrete SEIT model with age and infection age structures is formulated to investigate the dynamics of the disease spread. The basic reproduction number R0 is defined and used as the threshold parameter to character- ize the disease extinction or persistence. It is shown that the disease-free equilibrium is globally stable if R0 〈 1, and it is unstable if R0 〉 1. When R0 〉 1, there exists an endemic equilibrium, and the disease is uniformly persistent. The stability of the endemic equilibrium is investigated numerically.

关键词： Discrete epidemic model infection age structure basic reproduction number persistence.

PERMANENCE AND PERIODIC SOLUTION IN AN INTEGRODIFFERENTIAL SYSTEM WITH DISCRETE DIFFUSION

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Journal of Systems Science & Complexity 2003年第1期16卷 114-121页

作者： xiao yanni CHEN Lansun TANG Sanyi (Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100080, China) Academy of Mathematics and Systems Science Chinese Academy of Sciences 北京 100080

Dynamical characteristics of an integrodifferential modelling competitive sys-tem with diffusion are *** particular,we derive sufficient conditions for the permanence of species,existence of an attracting periodic sol... 详细信息

关键词： Permanence periodic solution global attractivity.

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PERMANENCE AND PERIODIC SOLUTION OF NONAUTONOMOUS DELAY LOTKA-VOLTERRA DIFFUSION SYSTEM

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Systems Science and Mathematical Sciences 1999年第4期12卷 344-349页

作者： xiao yanni(Institute of Mathematics, Academia Sinica, Beijing 100080, China)WANG Weidong(Deportment of Mathematics and Computer Hubei Institute for Nationalities, Enshi 445000, China)CHEN Jufang(Department of Mathematics, Shaanxi Normal University, Xi’an 中科院数学所北京 100080 湖北民族学院数学和计算机系湖北恩施 445000 陕西师范大学数学系陕西西安 710062

This paper analyzes permanence, existence and global attractivity of positiveperiodic solution in nonautonomous delay diffusive Lotka-Volterra competitive system fora patchstyle environment, by applying the invariant ... 详细信息

关键词： Permanence ultimately bounded domain diffusion rate periodic solution global attractivity.

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基于个体传染病模型研究个体行为改变对甲型H1N1的影响

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陕西师范大学学报（自然科学版） 2023年第5期51卷 1-10页

作者：闫琴玲肖燕妮长安大学理学院陕西西安710064 西安交通大学数学与统计学院陕西西安710049

个体行为在突发性传染病传播过程中起着重要作用,通过行为改变来减缓和控制突发性传染病传播的能力是应对策略的一个重要方面,因此了解个体行为改变如何影响突发性传染病的传播至关重要。基于2009年甲型H1N1流感(A/H1N1)数据,建立基于... 详细信息

个体行为在突发性传染病传播过程中起着重要作用,通过行为改变来减缓和控制突发性传染病传播的能力是应对策略的一个重要方面,因此了解个体行为改变如何影响突发性传染病的传播至关重要。基于2009年甲型H1N1流感(A/H1N1)数据,建立基于社交网络的个体决策心理模型(LHBM),将个体行为改变率嵌入个体水平的传播动力学模型(IBMs),并研究个体行为改变如何影响A/H1N1的动态变化。然后,基于IBMs,应用基于序列蒙特卡罗的近似贝叶斯计算方法(ABC SMC)估计未知参数。结果表明:IBMs能更准确地描述A/H1N1的传播过程,揭示个体行为改变对A/H1N1暴发的影响。此外,媒体宣传的重点应集中在如何引导个体的行为改变,而且个体的积极响应对于缓解和控制突发性传染病至关重要。

关键词：个体行为改变甲型H1N1流感个体行为模型 LHBM模型基于序列蒙特卡罗的近似贝叶斯计算方法

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