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Overview

MeSH Disease

Human Phenotype

There are no HP terms in the subcorpus


Transmission

Seroprevalence
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    Characterizing the Qatar advanced-phase SARS-CoV-2 epidemic

    Authors: Laith J Abu-Raddad; Hiam Chemaitelly; Houssein H Ayoub; Zaina Al Kanaani; Abdullatif Al Khal; Einas Al Kuwari; Adeel A Butt; Peter Coyle; Andrew Jeremijenko; Anvar Hassan Kaleeckal; Ali Nizar Latif; Robert C Owen; Hanan F Abdul Rahim; Samya A Al Abdulla; Mohamed G Al Kuwari; Mujeeb C Kandy; Hatoun Saeb; Shazia Nadeem N. Ahmed; Hamad Eid Al Romaihi; Devendra Bansal; Louise Dalton; Sheikh Mohammad Al Thani; Roberto Bertollini

    doi:10.1101/2020.07.16.20155317 Date: 2020-07-19 Source: medRxiv

    ABSTRACT Background: Qatar has a population of 2.8 million, over half of whom are expatriate craft and manual workers (CMW). We aimed to characterize the severe acute respiratory syndrome MESHD coronavirus 2 (SARS-CoV-2) epidemic in Qatar. Methods: A series of epidemiologic studies were conducted including analysis of the national SARS-CoV-2 PCR testing and hospitalization database, community surveys assessing current infection MESHD, ad-hoc PCR testing campaigns in workplaces and residential areas, serological testing SERO for antibody SERO on blood SERO specimens collected for routine clinical screening/management, national Coronavirus Diseases MESHD 2019 (COVID-19) death MESHD registry, and a mathematical model. Results: By July 10, 397,577 individuals had been PCR tested for SARS-CoV-2, of whom 110,986 were positive, a positivity cumulative rate of 27.9% (95% CI: 27.8-28.1%). PCR positivity of nasopharyngeal swabs in a national community survey (May 6-7) including 1,307 participants was 14.9% (95% CI: 11.5-19.0%); 58.5% of those testing positive were asymptomatic TRANS. Across 448 ad-hoc PCR testing campaigns in workplaces and residential areas including 26,715 individuals, pooled mean PCR positivity was 15.6% (95% CI: 13.7-17.7%). SARS-CoV-2 antibody SERO prevalence SERO was 24.0% (95% CI: 23.3-24.6%) in 32,970 residual clinical blood SERO specimens. Antibody SERO prevalence SERO was only 47.3% (95% CI: 46.2-48.5%) in those who had at least one PCR positive result, but it was 91.3% (95% CI: 89.5-92.9%) among those who were PCR positive >3 weeks before serology testing. There were substantial differences in exposure to infection MESHD by nationality and sex, reflecting risk differentials between the craft/manual workers and urban populations. As of July 5, case severity rate, based on the WHO severity classification, was 3.4% and case fatality rate was 1.4 per 1,000 persons. Model-estimated daily number of infections MESHD and active- infection MESHD prevalence SERO peaked at 22,630 and 5.7%, respectively, on May 21 and May 23. Attack rate TRANS (ever infection MESHD) was estimated at 53.5% on July 12. R0 TRANS ranged between 1.45-1.68 throughout the epidemic. Rt was estimated at 0.70 on June 15, which was hence set as onset date for easing of restrictions. Age TRANS was by far the strongest predictor of severe, critical, or fatal infection MESHD. Conclusions: Qatar has experienced a large SARS-CoV-2 epidemic that is rapidly declining, apparently due to exhaustion of susceptibles. The epidemic demonstrated a classic susceptible-infected-recovered 'SIR' dynamics with a rather stable R0 TRANS of about 1.6. The young demographic structure of the population, in addition to a resourced public health response, yielded a milder disease MESHD burden and lower mortality than elsewhere.

    Association between epidemic dynamics of Covid-19 infection MESHD and ABO blood SERO group types

    Authors: Yuefei Liu; Juergen M. Steinacker; Lisa Haeussinger; Alexander Dinse-Lambracht

    doi:10.1101/2020.07.12.20152074 Date: 2020-07-15 Source: medRxiv

    Background: Covid-19 pandemic is the most critical challenge nowadays for the manhood, and the infection MESHD and death MESHD cases are still speedily increasing. Since there are no available vaccine and specifically effective treatment, to break the infectious way of the pandemic remains the unique measure to efficiently combat Covid-19 infection MESHD. Understanding factors that affect the Covid-19 infection MESHD can help make better balance between activity restriction and infection MESHD dynamics. This study sought to investigate association between Covid-19 infection MESHD and blood SERO type distribution. Methods: The big data provided by World Health Organization and Johns Hopkins University were taken to assess epidemic dynamics of Covid-19 infection MESHD. Growth rate and doubling time of infection MESHD and death MESHD cases, reproductive number TRANS, infection MESHD and death MESHD cases in the mid-exponential phase were analyzed in relation to blood SERO type distribution. Results: Growth rate of infection MESHD and death MESHD cases correlated significantly to blood SERO type A proportion of the population positively while to blood SERO type B proportion negatively. In comparison with lower blood SERO type A population (< 30%) people with higher blood SERO type A ([≥] 30%) had more infection MESHD and death MESHD cases in the early exponential phase, higher growth rates, and shorter case doubling time for infection MESHD and death MESHD. Discussion: Covid-19 infection MESHD is significantly associated with blood SERO type distribution and people with blood SERO type A are more susceptible to Covid-19 infection MESHD and have higher epidemic dynamics and higher case fatality rate. The results of this study provide important and useful information for fighting Covid-19 pandemic.

    Modelling the impact of Plasma SERO Therapy and Immunotherapy for Recovery of COVID-19 Infected Individuals

    Authors: Nita H Shah; Ankush H Suthar; Ekta N Jayswal; Nehal Shukla; Jagdish Shukla

    doi:10.1101/2020.05.23.20110973 Date: 2020-05-24 Source: medRxiv

    Since the first case of COVID-19 was detected in Wuhan, China in December 2019, COVID-19 has become a pandemic causing a global economic and public health emergency MESHD. There is no known treatment or vaccine available for COVID-19 to date. Immunotherapy and plasma SERO therapy has been used with satisfactory efficacy over the past two decades in many viral infections MESHD like SARS (Systemic Acute Respiratory Syndrome MESHD), MERS (Middle East Respiratory Syndrome MESHD), and H1N1. Limited data from China show clinical benefit, radiological resolution, reduction in viral loads, and improved survival. Our aim is to create a mathematical model for COVID-19 transmission TRANS and then apply various control parameters to see their effects on recovery from COVID-19 disease MESHD. We have formulated a system of non-linear ordinary differential equations, calculated basic reproduction R0 TRANS, and applied five different controls (self-isolation, quarantine, herd immunity, immunotherapy, plasma SERO therapy) to test the effectiveness of control strategy. Control optimality was checked by Lagrangian functions. Numerical simulations and bifurcation analyses were carried out. The study concludes that the COVID-19 outbreak can be controlled up to a significant level three weeks after applying all the control strategies together. These strategies lead to a reduction in hospitalization and a rise in recovery from infection MESHD. Immunotherapy is highly effective initially in hospitalized infected individuals however better results were seen in the long term with plasma SERO therapy.

    The COVID-19 Pandemic: Model-Based Evaluation of Non-Pharmaceutical Interventions and Prognoses

    Authors: Alex De Visscher

    doi:10.21203/rs.3.rs-27139/v1 Date: 2020-05-05 Source: ResearchSquare

    An epidemiological model for COVID-19 was developed and implemented in MATLAB/GNU Octave for use by public health practitioners, policy makers and the general public. The model distinguishes four stages in the disease MESHD: infected, sick, seriously sick, and better. The model was preliminarily parameterized based on observations of the spread of the disease TRANS disease MESHD. The model assumes a case mortality rate of 1.5 %. Preliminary simulations with the model indicate that concepts such as “herd immunity” and “flattening the curve” are highly misleading in the context of this virus. Public policies based on these concepts are inadequate to protect the population. Only reducing the R0 TRANS of the virus below 1 is an effective strategy for maintaining the death MESHD burden of COVID-19 within the normal range of seasonal flu. The model is illustrated with the cases of Italy, France, and Iran, and is able to describe the number of deaths MESHD as a function of time in all these cases although future projections tend to slightly overestimate the number of deaths MESHD. The case mortality rate is still prone to large uncertainty, but modeling combined with an investigation of blood SERO donations in The Netherlands imposes a lower limit of 1 %.

    Fundamental principles of epidemic spread highlight the immediate need forlarge-scale serological surveys to assess the stage of the SARS-CoV-2 epidemic

    Authors: Jose Lourenco; Robert Paton; Mahan Ghafari; Moritz Kraemer; Craig Thompson; Peter Simmonds; Paul Klenerman; Sunetra Gupta

    doi:10.1101/2020.03.24.20042291 Date: 2020-03-26 Source: medRxiv

    The spread of a novel pathogenic infectious agent eliciting protective immunity is typically characterised by three distinct phases: (I) an initial phase of slow accumulation of new infections MESHD (often undetectable), (II) a second phase of rapid growth in cases of infection MESHD, disease MESHD and death MESHD, and (III) an eventual slow down of transmission TRANS due to the depletion of susceptible individuals, typically leading to the termination of the (first) epidemic wave. Before the implementation of control measures (e.g. social distancing, travel TRANS bans, etc) and under the assumption that infection MESHD elicits protective immunity, epidemiological theory indicates that the ongoing epidemic of SARS-CoV-2 will conform to this pattern. Here, we calibrate a susceptible-infected-recovered (SIR) model to data on cumulative reported SARS-CoV-2 associated deaths MESHD from the United Kingdom (UK) and Italy under the assumption that such deaths MESHD are well reported events that occur only in a vulnerable fraction of the population. We focus on model solutions which take into consideration previous estimates of critical epidemiological parameters such as the basic reproduction number TRANS ( R0 TRANS), probability of death MESHD in the vulnerable fraction of the population, infectious period TRANS and time from infection MESHD to death MESHD, with the intention of exploring the sensitivity SERO of the system to the actual fraction of the population vulnerable to severe disease MESHD and death MESHD. Our simulations are in agreement with other studies that the current epidemic wave in the UK and Italy in the absence of interventions should have an approximate duration of 2-3 months, with numbers of deaths MESHD lagging behind in time relative to overall infections MESHD. Importantly, the results we present here suggest the ongoing epidemics in the UK and Italy started at least a month before the first reported death MESHD and have already led to the accumulation of significant levels of herd immunity in both countries. There is an inverse relationship between the proportion currently immune and the fraction of the population vulnerable to severe disease MESHD. This relationship can be used to determine how many people will require hospitalisation (and possibly die) in the coming weeks if we are able to accurately determine current levels of herd immunity. There is thus an urgent need for investment in technologies such as virus (or viral pseudotype) neutralization assays and other robust assays which provide reliable read-outs of protective immunity, and for the provision of open access to valuable data sources such as blood SERO banks and paired samples of acute and convalescent sera from confirmed cases TRANS of SARS-CoV-2 to validate these. Urgent development and assessment of such tests should be followed by rapid implementation at scale to provide real-time data. These data will be critical to the proper assessment of the effects of social distancing and other measures currently being adopted to slow down the case incidence and for informing future policy direction.

The ZB MED preprint Viewer preVIEW includes all COVID-19 related preprints from medRxiv and bioRxiv, from ChemRxiv, from ResearchSquare, from arXiv and from Preprints.org and is updated on a daily basis (7am CET/CEST).

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MeSH Disease
Human Phenotype
Transmission
Seroprevalence


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