### Overview

MeSH Disease

Infections (173)

Disease (170)

Death (94)

Human Phenotype

Pneumonia (31)

Fever (24)

Cough (20)

Falls (7)

Fatigue (5)

Transmission

Seroprevalence
displaying 1 - 10 records in total 359
records per page

### Genomic epidemiology reveals transmission TRANS patterns and dynamics of SARS-CoV-2 in Aotearoa New Zealand

Authors: Jemma L Geoghegan; Xiaoyun Ren; Matthew Storey; James Hadfield; Lauren Jelley; Sarah Jefferies; Jill Sherwood; Shevaun Paine; Sue Huang; Jordan Douglas; Fabio K L Mendes; Andrew Sporle; Michael G Baker; David R Murdoch; Nigel French; Colin R Simpson; David Welch; Alexei J Drummond; Edward C Holmes; Sebastian Duchene; Joep de Ligt

doi:10.1101/2020.08.05.20168930 Date: 2020-08-06 Source: medRxiv

New Zealand, a geographically remote Pacific island with easily sealable borders, implemented a nation-wide lockdown of all non-essential services to curb the spread of COVID-19. New Zealand has now effectively eliminated the virus, with low numbers of new cases limited to new arrivals in managed quarantine facilities at the border. Here, we generated 649 SARS-CoV-2 genome sequences from infected patients in New Zealand with samples collected between 26 February and 22 May 2020, representing 56% of all confirmed cases TRANS in this time period. Despite its remoteness, the viruses imported into New Zealand represented nearly all of the genomic diversity sequenced from the global virus population. The proportion of D614G variants in the virus spike protein increased over time due to an increase in their importation frequency, rather than selection within New Zealand. These data also helped to quantify the effectiveness of public health interventions. For example, the effective reproductive number TRANS, Re, of New Zealand's largest cluster decreased from 7 to 0.2 within the first week of lockdown. Similarly, only 19% of virus introductions into New Zealand resulted in a transmission TRANS lineage of more than one additional case. Most of the cases that resulted in a transmission TRANS lineage originated from North America, rather than from Asia where the virus first emerged or from the nearest geographical neighbour, Australia. Genomic data also helped link more infections MESHD to a major transmission TRANS cluster than through epidemiological data alone, providing probable sources of infections MESHD for cases in which the source was unclear. Overall, these results demonstrate the utility of genomic pathogen surveillance to inform public health and disease MESHD mitigation.

### Inhomogeneous mixing and asynchronic transmission TRANS between local outbreaks account for the spread of COVID-19 epidemics

Authors: Carlos I Mendoza

doi:10.1101/2020.08.04.20168443 Date: 2020-08-06 Source: medRxiv

The ongoing epidemic of COVID-19 originated in China has reinforced the need to develop epidemiological models capable of describing the progression of the disease MESHD to be of use in the formulation of mitigation policies. Here, this problem is addressed using a metapopulation approach to show that the delay in the transmission TRANS of the spread between different subsets of the total population, can be incorporated into a SIR framework through a time-dependent transmission TRANS rate. Thus, the reproduction number TRANS decreases with time despite the population dynamics remains uniform and the depletion of susceptible individuals is small. The obtained results are consistent with the early subexponential growth observed in the cumulated number of confirmed cases TRANS even in the absence of containment measures. We validate our model by describing the evolution of the COVID-19 using real data from different countries with an emphasis in the case of Mexico and show that it describes correctly also the long-time dynamics of the spread. The proposed model yet simple is successful at describing the onset and progression of the outbreak and considerably improves accuracy of predictions over traditional compartmental models. The insights given here may probe be useful to forecast the extent of the public health risks of epidemics and thus improving public policy-making aimed at reducing such risks.

### Epidemiological characteristics of SARS-COV-2 in Myanmar

Authors: Aung Min Thway; Htun Tayza; Tun Tun Win; Ye Minn Tun; Moe Myint Aung; Yan Naung Win; Kyaw M Tun

doi:10.1101/2020.08.02.20166504 Date: 2020-08-04 Source: medRxiv

Coronavirus disease MESHD (COVID-19) is an infectious disease MESHD caused by a newly discovered severe acute respiratory syndrome MESHD coronavirus 2 (SARS-CoV-2). In Myanmar, first COVID-19 reported cases were identified on 23rd March 2020. There were 336 reported confirmed cases TRANS, 261 recovered and 6 deaths MESHD through 13th July 2020. The study was a retrospective case series and all COVID-19 confirmed cases TRANS from 23rd March to 13th July 2020 were included. The data series of COVID-19 cases were extracted from the daily official reports of the Ministry of Health and Sports (MOHS), Myanmar and Centers for Disease MESHD Control and Prevention (CDC), Myanmar. Among 336 confirmed cases TRANS, there were 169 cases with reported transmission TRANS events. The median serial interval TRANS was 4 days (IQR 3, 2-5) with the range of 0 - 26 days. The mean of the reproduction number TRANS was 1.44 with (95% CI = 1.30-1.60) by exponential growth method and 1.32 with (95% CI = 0.98-1.73) confident interval by maximum likelihood method. This study outlined the epidemiological characteristics and epidemic parameters of COVID-19 in Myanmar. The estimation parameters in this study can be comparable with other studies and variability of these parameters can be considered when implementing disease MESHD control strategy in Myanmar.

### Analysis of COVID-19 and comorbidity co- infection MESHD Model with Optimal Control

Authors: Dr. Andrew Omame; Nometa Ikenna

doi:10.1101/2020.08.04.20168013 Date: 2020-08-04 Source: medRxiv

The new coronavirus disease MESHD 2019 (COVID-19) infection MESHD is a double challenge for people infected with comorbidities such as cardiovascular and cerebrovascular diseases MESHD and diabetes. Comorbidities have been reported to be risk factors for the complications of COVID-19. In this work, we develop and analyze a mathematical model for the dynamics of COVID-19 infection MESHD in order to assess the impacts of prior comorbidity on COVID-19 complications and COVID-19 re- infection MESHD. The model is simulated using data relevant to the dynamics of the diseases MESHD in Lagos, Nigeria, making predictions for the attainment of peak periods in the presence or absence of comorbidity. The model is shown to undergo the phenomenon of backward bifurcation caused by the parameter accounting for increased susceptibility to COVID-19 infection MESHD by comorbid susceptibles as well as the rate of re- infection MESHD by those who have recovered from a previous COVID-19 infection MESHD. Sensitivity SERO analysis of the model when the population of individuals co-infected with COVID-19 and comorbidity is used as response function revealed that the top ranked parameters that drive the dynamics of the co- infection MESHD model are the effective contact rate for COVID-19 transmission TRANS, $\beta\sst{cv}$, the parameter accounting for increased susceptibility to COVID-19 by comorbid susceptibles, $\chi\sst{cm}$, the comorbidity development rate, $\theta\sst{cm}$, the detection rate for singly infected and co-infected individuals, $\eta_1$ and $\eta_2$, as well as the recovery rate from COVID-19 for co-infected individuals, $\varphi\sst{i2}$. Simulations of the model reveal that the cumulative confirmed cases TRANS (without comorbidity) may get up to 180,000 after 200 days, if the hyper susceptibility rate of comorbid susceptibles is as high as 1.2 per day. Also, the cumulative confirmed cases TRANS (including those co-infected with comorbidity) may be as high as 1000,000 cases by the end of November, 2020 if the re- infection MESHD rates for COVID-19 is 0.1 per day. It may be worse than this if the re- infection MESHD rates increase higher. Moreover, if policies are strictly put in place to step down the probability of COVID-19 infection MESHD by comorbid susceptibles to as low as 0.4 per day and step up the detection rate for singly infected individuals to 0.7 per day, then the reproduction number TRANS can be brought very low below one, and COVID-19 infection MESHD eliminated from the population. In addition, optimal control and cost-effectiveness analysis of the model reveal that the the strategy that prevents COVID-19 infection MESHD by comorbid susceptibles has the least ICER and is the most cost-effective of all the control strategies for the prevention of COVID-19.

### Risk stratification as a tool to rationalize quarantine among health care workers exposed to COVID-19 cases - Evidence from a tertiary healthcare centre in India

Authors: Ravneet Kaur; Shashi Kant; Mohan Bairwa; Arvind Kumar; Shivram Dhakad; Vignesh Dwarakanathan; Aftab Ahmad; Pooja Pandey; Arti Kapil; Rakesh Lodha; Naveet Wig

doi:10.1101/2020.07.31.20166264 Date: 2020-08-04 Source: medRxiv

Background: Quarantine of healthcare workers (HCWs) exposed to COVID 19 confirmed cases TRANS is a well known strategy for limiting the transmission TRANS of infection MESHD. However, there is a need for evidence-based guidelines for the quarantine of HCWs in COVID 19. Methods: We describe our experience of contact tracing TRANS and risk stratification of 3853 HCWs who were exposed to confirmed COVID-19 cases in a tertiary health care institution in India. We developed an algorithm, on the basis of risk stratification, to rationalize quarantine among HCWs. Risk stratification was based on the duration of exposure, distance from the patient, and appropriateness of personal protection equipment (PPE) usage. Only high-risk contacts were quarantined for 14 days. They underwent testing for COVID 19 after five days of exposure, while low risk contacts continued their work with adherence to physical distancing, hand hygiene, and appropriate use of PPE. The low-risk contacts were encouraged to monitor for symptoms and report for COVID 19 screening if fever MESHD fever HP, cough MESHD cough HP, or shortness of breath occurred. We followed up all contacts for 14 days from the last exposure and observed for symptoms of COVID 19 and test positivity. Results and interpretation: Out of total 3853 contacts, 560 (14.5%) were categorized as high-risk contacts, and 40 of them were detected positive for COVID 19, with a test positivity rate of 7.1% (95% CI = 5.2, 9.6). Overall, 118 (3.1%) of all contacts tested positive. Our strategy prevented 3215 HCWs from being quarantined and saved 45,010 person-days of health workforce until June 8, 2020, in the institution. We conclude that exposure-based risk stratification and quarantine of HCWs is a viable strategy to prevent unnecessary quarantine, in a healthcare institution.

### Data-driven modeling and forecasting of COVID-19 outbreak for public policy making

Authors: Agus Hasan; Endah Putri; Hadi Susanto; Nuning Nuraini

doi:10.1101/2020.07.30.20165555 Date: 2020-08-02 Source: medRxiv

This paper presents a data-driven approach for COVID-19 outbreak modeling and forecasting, which can be used by public policy and decision makers to control the outbreak through Non-Pharmaceutical Interventions (NPI). First, we apply an extended Kalman filter (EKF) to a discrete-time stochastic augmented compartmental model to estimate the time-varying effective reproduction number TRANS Rt. We use daily confirmed cases TRANS, active cases, recovered cases, deceased cases, Case-Fatality-Rate (CFR), and infectious time as inputs for the model. Furthermore, we define a Transmission TRANS Index (TI) as a ratio between the instantaneous and the maximum value of the effective reproduction number TRANS. The value of TI shows the disease MESHD transmission TRANS in a contact between a susceptible and an infectious individual due to current measures such as physical distancing and lock-down relative to a normal condition. Based on the value of TI, we forecast different scenarios to see the effect of relaxing and tightening public measures. Case studies in three countries are provided to show the practicability of our approach.

### Modeling latent infection MESHD transmissions TRANS through biosocial stochastic dynamics

doi:10.1101/2020.07.30.20164491 Date: 2020-08-01 Source: medRxiv

The events of the recent SARS-CoV-02 epidemics have shown the importance of social factors, especially given the large number of asymptomatic TRANS cases that effectively spread the virus, which can cause a medical emergency MESHD to very susceptible individuals. Besides, the SARS-CoV-02 virus survives for several hours on different surfaces, where a new host can contract it with a delay. These passive modes of infection MESHD transmission TRANS remain an unexplored area for traditional mean-field epidemic models. Here, we design an agent-based model for simulations of infection MESHD transmission TRANS in an open system driven by the dynamics of social activity; the model takes into account the personal characteristics of individuals, as well as the survival time of the virus and its potential mutations. A growing bipartite graph embodies this biosocial process, consisting of active carriers TRANS (host) nodes that produce viral nodes during their infectious period TRANS. With its directed edges passing through viral nodes between two successive hosts, this graph contains complete information about the routes leading to each infected individual. We determine temporal fluctuations of the number of exposed and the number of infected individuals, the number of active carriers TRANS and active viruses at hourly resolution. The simulated processes underpin the latent infection MESHD transmissions TRANS, contributing significantly to the spread of the virus within a large time window. More precisely, being brought by social dynamics and exposed to the currently existing infection MESHD, an individual passes through the infectious state until eventually spontaneously recovers or otherwise is moves to a controlled hospital environment. Our results reveal complex feedback mechanisms that shape the dependence of the infection MESHD curve on the intensity of social dynamics and other sociobiological factors. In particular, the results show how the lockdown effectively reduces the spread of infection MESHD and how it increases again after the lockdown is removed. Furthermore, a reduced level of social activity but prolonged exposure of susceptible individuals have adverse effects. On the other hand, virus mutations that can gradually reduce the transmission TRANS rate by hopping to each new host along the infection MESHD path can significantly reduce the extent of the infection MESHD, but can not stop the spreading without additional social strategies. Our stochastic processes, based on graphs at the interface of biology and social dynamics, provide a new mathematical framework for simulations of various epidemic control strategies with high temporal resolution and virus traceability.

### Household transmission TRANS of SARS-CoV-2: a systematic review and meta-analysis of secondary attack rate TRANS

Authors: Zachary J. Madewell; Yang Yang; Ira M. Longini Jr.; M. Elizabeth Halloran; Natalie E. Dean

doi:10.1101/2020.07.29.20164590 Date: 2020-08-01 Source: medRxiv

Background: Severe acute respiratory syndrome MESHD coronavirus 2 (SARS-CoV-2) is spread by direct, indirect, or close contact TRANS with infected people via infected respiratory droplets or saliva. Crowded indoor environments with sustained close contact TRANS and conversations are a particularly high-risk setting. Methods: We performed a meta-analysis through July 29, 2020 of SARS-CoV-2 household secondary attack rate TRANS ( SAR TRANS), disaggregating by several covariates (contact type, symptom status, adult TRANS/ child TRANS contacts, contact sex, relationship to index case, index case sex, number of contacts in household TRANS, coronavirus). Findings: We identified 40 relevant published studies that report household secondary transmission TRANS. The estimated overall household SAR TRANS was 18.8% (95% confidence interval [CI]: 15.4%-22.2%), which is higher than previously observed SARs for SARS-CoV and MERS-CoV. We observed that household SARs were significantly higher from symptomatic index cases than asymptomatic TRANS index cases, to adult TRANS contacts than children TRANS contacts, to spouses than other family contacts, and in households TRANS with one contact than households TRANS with three or more contacts. Interpretation: To prevent the spread of SARS-CoV-2, people are being asked to stay at home worldwide. With suspected or confirmed infections TRANS infections MESHD referred to isolate at home, household transmission TRANS will continue to be a significant source of transmission TRANS.

### The Effect of Temperature Upon Transmission TRANS Of COVID-19 Australia And Egypt Case Study.

doi:10.21203/rs.3.rs-51746/v1 Date: 2020-07-31 Source: ResearchSquare

BackgroundSeveral previous studies have recognized the effect of air temperature on the survival and transmission TRANS of viruses and germs. The current study investigated the effect of air temperature on the transmission TRANS of coronavirus covid-19 by monthly temperature averages maps analyzing.MethodsThe study demonstrated the relationship between temperature and transmission TRANS speed of Covid-19 virus, It confirmed that the most appropriate average temperature for virus activity and transmission TRANS ranges between 13-24 ° C, by analyzing the maps of monthly temperature averages in Egypt and Australia.ResultsThe study reached, through cartographic analysis, to confirm the relationship between temperature and increase in the number of confirmed cases TRANS of covid-19, This study confirmed that the most appropriate average temperature for virus activity and transmission TRANS ranges between 13-24 ° C, by analyzing the maps of monthly temperature averages in Egypt and Australia. But the effect of the climate does not prevent the virus from being transmitted from one person to another through close contact TRANS or use of personal tools infected with the Corona virus, or crowding in air-conditioned places.Therefore, failure of individuals to follow the instructions for social distance and wearing a mask will lead to the transmission TRANS of the virus, even in hot climates.ConclusionsResults support that the most appropriate average temperature for the survival transmission TRANS of COVID-19 ranges between 13-24 ° C. Australia and Egypt are models to confirm the relationship between temperature and COVID-19 activity and spread.

### Close-range exposure to a COVID-19 carrier TRANS: transmission TRANS trends in the respiratory tract and estimation of infectious dose

Authors: Saikat Basu

doi:10.1101/2020.07.27.20162362 Date: 2020-07-29 Source: medRxiv

How respiratory physiology and airflow therein proceed to impact SARS-CoV-2 transmission TRANS, leading to the initial infection MESHD, is an open question. An answer can help determine the susceptibility of an individual on exposure to a COVID-2019 carrier TRANS and can also quantify the still-unknown infectious dose for the disease MESHD. Combining computational fluid mechanics-based tracking of respiratory transport in anatomic domains with sputum assessment data from hospitalized patients and earlier measurements of ejecta size distribution during regular speech - this study shows that targeted deposition at the initial nasopharyngeal infection MESHD sites peaks over the droplet size range of 2.5 - 19 , and reveals that the number of virions that can establish the infection MESHD is at most of O(100).

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 All None MeSH Disease Human Phenotype Transmission Seroprevalence

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