### Overview

MeSH Disease

Disease (58)

Infections (48)

Death (35)

Human Phenotype

Pneumonia (5)

Falls (4)

Fever (3)

Cough (2)

Anxiety (2)

Transmission

Seroprevalence
displaying 1 - 10 records in total 121
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### 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.

### Mathematical modeling of the transmission TRANS of SARS-CoV-2 '' Evaluating the impact of isolation in Sao Paulo State (Brazil) and lockdown in Spain associated with protective measures on the epidemic of covid-19

Authors: Hyun Mo Yang; Luis Pedro Lombardi Jr.; Fabio Fernandes Morato Castro; Ariana Campos Yang

doi:10.1101/2020.07.30.20165191 Date: 2020-08-01 Source: medRxiv

Coronavirus disease MESHD 2019 (covid-19), with the fatality rate in elder (60 years old or more) being much higher than young (60 years old or less) patients, was declared a pandemic by the World Health Organization on March 11, 2020. Taking into account this age TRANS-dependent fatality rate, a mathematical model considering young and elder subpopulations was formulated based on the natural history of covid-19 to study the transmission TRANS of the SARS-CoV-2. This model can be applied to study the epidemiological scenario resulting from the adoption of isolation or lockdown in many countries to control the rapid propagation of covid-19. We chose as examples the isolation adopted in Sao Paulo State (Brazil) in the early phase but not at the beginning of the epidemic, and the lockdown implemented in Spain when the number of severe covid-19 cases was increasing rapidly. Based on the data collected from Sa o Paulo State and Spain, the model parameters were evaluated and we obtained higher estimation for the basic reproduction number TRANS R0 TRANS (9.24 for Sao Paulo State, and 8 for Spain) compared to the currently accepted estimation of R0 TRANS around 3. The model allowed to explain the flattening of the epidemic curves by isolation in Sao Paulo State and lockdown in Spain when associated with the protective measures (face mask and social distancing) adopted by the population. However, a simplified mathematical model providing lower estimation for R0 TRANS did not explain the flattening of the epidemic curves. The implementation of the isolation in Sa o Paulo State before the rapidly increasing phase of the epidemic enlarged the period of the first wave of the epidemic and delayed its peak, which are the desirable results of isolation to avoid the overloading in the health care system.

### Isolation Considered Epidemiological Model for the Prediction of COVID-19 Trend in Tokyo, Japan

Authors: Motoaki Utamura; Makoto Koizumi; Seiichi Kirikami

doi:10.1101/2020.07.31.20165829 Date: 2020-07-31 Source: medRxiv

Background: Coronavirus Disease MESHD 2019 (COVID19) currently poses a global public health threat. Although no exception, Tokyo, Japan was affected at first by only a small epidemic. Medical collapse nevertheless nearly happened because no predictive method existed for counting patients. A standard SIR epidemiological model and its derivatives predict susceptible, infectious, and removed (recovered/ deaths MESHD) cases but ignore isolation of confirmed cases TRANS. Predicting COVID19 trends with hospitalized and infectious people in field separately is important to prepare beds and develop quarantine strategies. Methods: Time-series COVID19 data from February 28 to May 23, 2020 in Tokyo were adopted for this study. A novel epidemiological model based on delay differential equation was proposed. The model can evaluate patients in hospitals and infectious cases in the field. Various data such as daily new cases, cumulative infections MESHD, patients in hospital, and PCR test positivity ratios were used to examine the model. This approach derived an alternative formulation equivalent to the standard SIR model. Its results were compared quantitatively with those of the present isolation model. Results: The basic reproductive number TRANS, inferred as 2.30, is a dimensionless parameter composed of modeling parameters. Effects of intervention to mitigate the epidemic spread were assessed a posteriori. An exit policy of how and when to release a statement of emergency MESHD was also assessed using the model. Furthermore, results suggest that the rapid isolation of infectious cases has a large potential to effectively mitigate the spread of infection MESHD and restores social and economic activities safely. Conclusions: A novel mathematical model was proposed and examined using COVID19 data for Tokyo. Results show that shortening the period from infection MESHD to hospitalization is effective against outbreak without rigorous public health intervention and control. Faster and precise case cluster detection and wider and quicker introduction of testing measures are strongly recommended.

### The effective reproductive number TRANS (Rt) of COVID-19 and its relationship with social distancing

Authors: Lucas Jardim Sr.; Jose Alexandre Diniz-Filho Sr.; Thiago Fernando Rangel Sr.; Cristiana Maria Toscano II

doi:10.1101/2020.07.28.20163493 Date: 2020-07-29 Source: medRxiv

The expansion of the new coronavirus disease MESHD (COVID-19) triggered a renewed public interest in epidemiological models and on how parameters can be estimated from observed data. Here we investigated the relationship between average number of transmissions TRANS though time, the reproductive number TRANS Rt, and social distancing index as reported by mobile phone data service inloco, for Goias State, Brazil, between March and June 2020. We calculated Rt values using EpiEstim package in R-plataform for confirmed cases TRANS incidence curves. We found a correlation equal to -0.72 between Rt values for confirmed cases TRANS and isolation index at a time lag of 8 days. As the Rt values were paired with center of the moving window of 7 days, the delay matches the mean incubation period TRANS of the virus. Our findings reinforce that isolation index can be an effective surrogate for modeling and epidemiological analyses and, more importantly, can be an useful metrics for anticipating the need for early interventions, a critical issue in public health.

### Epidemic response to physical distancing policies and their impact on the outbreak risk

Authors: Fabio Vanni; David Lambert; Luigi Palatella

id:2007.14620v2 Date: 2020-07-29 Source: arXiv

We introduce a theoretical framework that highlights the impact of physical distancing variables such as human mobility and physical proximity on the evolution of epidemics and, crucially, on the reproduction number TRANS. In particular, in response to the coronavirus disease MESHD (CoViD-19) pandemic, countries have introduced various levels of 'lockdown' to reduce the number of new infections MESHD. Specifically we use a collisional approach to an infection MESHD- age TRANS structured model described by a renewal equation for the time homogeneous evolution of epidemics. As a result, we show how various contributions of the lockdown policies, namely physical proximity and human mobility, reduce the impact of SARS-CoV-2 and mitigate the risk of disease MESHD resurgence. We check our theoretical framework using real-world data on physical distancing with two different data repositories, obtaining consistent results. Finally, we propose an equation for the effective reproduction number TRANS which takes into account types of interactions among people, which may help policy makers to improve remote-working organizational structure.

### Epidemic Dynamics of COVID-19 Based on SEAIUHR Model Considering Asymptomatic TRANS Cases in Henan Province, China

Authors: Chunyu Li; Yuchen Zhu; Chang Qi; Lili Liu; Dandan Zhang; Xu Wang; Kaili She; Yan Jia; Tingxuan Liu; Momiao Xiong; Xiujun Li

doi:10.21203/rs.3.rs-50050/v1 Date: 2020-07-28 Source: ResearchSquare

Background New coronavirus disease MESHD (COVID-19), an infectious disease MESHD caused by a type of novel coronavirus, has emerged in various countries since the end of 2019 and caused a global pandemic. Many infected people went undetected because their symptoms were mild or asymptomatic TRANS, but the proportion and infectivity of asymptomatic infections MESHD asymptomatic TRANS remained unknown. Therefore, in this paper, we analyzed the proportion and infectivity of asymptomatic TRANS cases, as we as the prevalence SERO of COVID-19 in Henan province.Methods We constructed SEAIUHR model based on COVID-19 cases reported from 21 January to 26 February 2020 in Henan province to estimate the proportion and infectivity of asymptomatic TRANS cases, as we as the change of effective reproductive number TRANS, $${R}_{t}$$. At the same time, we simulated the changes of cases in different scenarios by changing the time and intensity of the implementation of prevention and control measures.Results The proportion of asymptomatic TRANS cases among COVID-19 infected individuals was 42% and infectivity of asymptomatic TRANS cases was 10% of that symptomatic ones. The basic reproductive number$${R TRANS}_{0}$$=2.73, and $${R}_{t}$$ dropped below 1 on 1 February under a series of measures. If measures were taken five days earlier, the number of cases would be reduced by 2/3, and after 5 days the number would more than triple.Conclusions In Henan Province, the COVID-19 epidemic spread rapidly in the early stage, and there were a large number of asymptomatic TRANS infected individuals with relatively low infectivity. However, the epidemic was quickly brought under control with national measures, and the earlier measures were implemented, the better.

### INDEPENDENT ASSOCIATION OF METEOROLOGICAL CHARACTERISTICS WITH INITIAL SPREAD OF COVID-19 IN INDIA

Authors: Hemant Kulkarni; Harshwardhan Vinod Khandait; Uday Wasudeorao Narlawar; Pragati G Rathod; Manju Mamtani

doi:10.1101/2020.07.20.20157784 Date: 2020-07-26 Source: medRxiv

Whether weather plays a part in the transmissibility TRANS of the novel COronaVIrus Disease MESHD-19 (COVID-19) is still not established. We tested the hypothesis that meteorological factors (air temperature, relative humidity, air pressure, wind speed and rainfall) are independently associated with transmissibility TRANS of COVID-19 quantified using the basic reproduction rate ( R0 TRANS). We used publicly available datasets on daily COVID-19 case counts (total n = 108,308), three-hourly meteorological data and community mobility data over a three-month period. Estimated R0 TRANS varied between 1.15-1.28. Mean daily air temperature (inversely) and wind speed (positively) were significantly associated with time dependent R0 TRANS, but the contribution of countrywide lockdown to variability in R0 TRANS was over three times stronger as compared to that of temperature and wind speed combined. Thus, abating temperatures and easing lockdown may concur with increased transmissibility TRANS of COVID-19.

### Regional variability in time-varying transmission TRANS potential of COVID-19 in South Korea

Authors: Eunha Shim; Gerardo Chowell

doi:10.1101/2020.07.21.20158923 Date: 2020-07-22 Source: medRxiv

In South Korea, the total number of the 2019 novel coronavirus disease MESHD (COVID-19) cases is 13,711 including 293 deaths MESHD as of July 18, 2020. To examine the change of the growth rate of the outbreak, we present estimates of the transmissibility TRANS of COVID-19 in the four most affected regions in the country: Seoul, Gyeonggi Province, Gyeongbuk Province, and Daegu. The daily confirmed COVID-19 cases in these regions were extracted from publicly available sources. We estimated the time-varying reproduction numbers TRANS in these regions by using the renewable equation determined by the serial interval TRANS of COVID-19. In Seoul and Gyeonggi Province, the first major peak of COVID-19 occurred in early March, with the estimated reproduction number TRANS in February being as high as 4.24 and 8.86, respectively. In Gyeongbuk Province, the reproduction number TRANS reached 3.49 in February 8 and declined to a value below 1.00 on March 10, 2020, and similarly in Daegu, it decreased from 4.38 to 1.00 between February 5 and March 5. However, the loosening of the restrictions imposed by the government has triggered a resurgence of new cases in all regions considered, resulting in a reproduction number TRANS in May 2020 estimated at 3.04 and 4.78 in Seoul and Gyeonggi Province, repectively. Even though our findings indicate the effectiveness of the control measures against COVID-19 in Korea, they also indicate the potential resurgence and sustained transmission TRANS of COVID-19, supporting the continuous implementation of social distancing measures to control the outbreak.

### 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.

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 All None MeSH Disease Human Phenotype Transmission Seroprevalence

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