《MedRixv,2月11日,Assessing the plausibility of subcritical transmission of 2019-nCoV in the United States》

  • 来源专题:COVID-19科研动态监测
  • 编译者: xuwenwhlib
  • 发布时间:2020-02-12
  • Assessing the plausibility of subcritical transmission of 2019-nCoV in the United States

    Seth Blumberg, Thomas M Lietman, Travis C Porco

    doi: https://doi.org/10.1101/2020.02.08.20021311

    Abstract

    Abstract: The 2019-nCoV outbreak has raised concern of global spread. While person-to-person transmission within the Wuhan district has led to a large outbreak, the transmission potential outside of the region remains unclear. Here we present a simple approach for determining whether the upper limit of the confidence interval for the reproduction number exceeds one for transmission in the United States, which would allow endemic transmission. As of February 7, 2020, the number of cases in the United states support subcritical transmission, rather than ongoing transmission. However, this conclusion can change if pre-symptomatic cases resulting from human-to-human transmission have not yet been identified.

    *注,本文为预印本论文手稿,是未经同行评审的初步报告,其观点仅供科研同行交流,并不是结论性内容,请使用者谨慎使用.

  • 原文来源:https://www.medrxiv.org/content/10.1101/2020.02.08.20021311v1
相关报告
  • 《MedRixv,2月11日,Transmission Dynamics of 2019-nCoV in Malaysia》

    • 来源专题:COVID-19科研动态监测
    • 编译者:xuwenwhlib
    • 发布时间:2020-02-12
    • Transmission Dynamics of 2019-nCoV in Malaysia Jane Labadin, Boon Hao Hong doi: https://doi.org/10.1101/2020.02.07.20021188 Abstract This paper focuses on the formulation of a deterministic 2019-nCov transmission model by considering the exposed and recovered populations with immunity. The scenario of the simulation is depicted based on the patient zero in Malaysia. The transmission model is found to be able to predict the next confirmed case given a single case introduced in a fully susceptible population. The mathematical model is developed based on the SEIR model which has susceptible, exposed, infectious and recovered populations. The system of equations which were obtained were solved numerically and the simulation results were analyzed. The analysis includes the impact of the disease if no control is taken. *注,本文为预印本论文手稿,是未经同行评审的初步报告,其观点仅供科研同行交流,并不是结论性内容,请使用者谨慎使用.
  • 《MedRixv,2月11日,Feasibility of controlling 2019-nCoV outbreaks by isolation of cases and contacts》

    • 来源专题:COVID-19科研动态监测
    • 编译者:xuwenwhlib
    • 发布时间:2020-02-12
    • Feasibility of controlling 2019-nCoV outbreaks by isolation of cases and contacts Joel Hellewell, Sam Abbott, Amy Gimma, Nikos I Bosse, Christopher I Jarvis, Timothy W Russell, James D Munday, Adam J Kucharski, W John Edmunds, CMMID nCoV working group, Sebastian Funk, Rosalind M Eggo doi: https://doi.org/10.1101/2020.02.08.20021162 Abstract Background: To assess the viability of isolation and contact tracing to control onwards transmission from imported cases of 2019-nCoV. Methods: We developed a stochastic transmission model, parameterised to the 2019-nCoV outbreak. We used the model to quantify the potential effectiveness of contact tracing and isolation of cases at controlling a 2019 nCoV-like pathogen. We considered scenarios that varied in: the number of initial cases; the basic reproduction number R0; the delay from symptom onset to isolation; the probability contacts were traced; the proportion of transmission that occurred before symptom onset, and the proportion of subclinical infections. We assumed isolation prevented all further transmission in the model. Outbreaks were deemed controlled if transmission ended within 12 weeks or before 5000 cases in total. We measured the success of controlling outbreaks using isolation and contact tracing, and quantified the weekly maximum number of cases traced to measure feasibility of public health effort. Findings: While simulated outbreaks starting with only 5 initial cases, R0 of 1.5 and little transmission before symptom onset could be controlled even with low contact tracing probability, the prospects of controlling an outbreak dramatically dropped with the number of initial cases, with higher R0, and with more transmission before symptom onset. Across different initial numbers of cases, the majority of scenarios with an R0 of 1.5 were controllable with under 50% of contacts successfully traced. For R0 of 2.5 and 3.5, more than 70% and 90% of contacts respectively had to be traced to control the majority of outbreaks. The delay between symptom onset and isolation played the largest role in determining whether an outbreak was controllable for lower values of R0. For higher values of R0 and a large initial number of cases, contact tracing and isolation was only potentially feasible when less than 1% of transmission occurred before symptom onset. Interpretation: We found that in most scenarios contact tracing and case isolation alone is unlikely to control a new outbreak of 2019-nCov within three months. The probability of control decreases with longer delays from symptom onset to isolation, fewer cases ascertained by contact tracing, and increasing transmission before symptoms. This model can be modified to reflect updated transmission characteristics and more specific definitions of outbreak control to assess the potential success of local response efforts. *注,本文为预印本论文手稿,是未经同行评审的初步报告,其观点仅供科研同行交流,并不是结论性内容,请使用者谨慎使用.