Covid19 surveillance model in habitations.pdf

The Lancet Infectious Diseases, 2020

Background WHO has called for increased testing in response to the COVID-19 pandemic, but countries have taken different approaches and the effectiveness of alternative strategies is unknown. We aimed to investigate the potential impact of different testing and isolation strategies on transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods We developed a mathematical model of SARS-CoV-2 transmission based on infectiousness and PCR test sensitivity over time since infection. We estimated the reduction in the effective reproduction number (R) achieved by testing and isolating symptomatic individuals, regular screening of high-risk groups irrespective of symptoms, and quarantine of contacts of laboratory-confirmed cases identified through test-and-trace protocols. The expected effectiveness of different testing strategies was defined as the percentage reduction in R. We reviewed data on the performance of antibody tests reported by the Foundation for Innovative New Diagnostics and examined their implications for the use of so-called immunity passports. Findings If all individuals with symptoms compatible with COVID-19 self-isolated and self-isolation was 100% effective in reducing onwards transmission, self-isolation of symptomatic individuals would result in a reduction in R of 47% (95% uncertainty interval [UI] 32-55). PCR testing to identify SARS-CoV-2 infection soon after symptom onset could reduce the number of individuals needing to self-isolate, but would also reduce the effectiveness of self-isolation (around 10% would be false negatives). Weekly screening of health-care workers and other high-risk groups irrespective of symptoms by use of PCR testing is estimated to reduce their contribution to SARS-CoV-2 transmission by 23% (95% UI 16-40), on top of reductions achieved by self-isolation following symptoms, assuming results are available at 24 h. The effectiveness of test and trace depends strongly on coverage and the timeliness of contact tracing, potentially reducing R by 26% (95% UI 14-35) on top of reductions achieved by self-isolation following symptoms, if 80% of cases and contacts are identified and there is immediate testing following symptom onset and quarantine of contacts within 24 h. Among currently available antibody tests, performance has been highly variable, with specificity around 90% or lower for rapid diagnostic tests and 95-99% for laboratory-based ELISA and chemiluminescent assays. Interpretation Molecular testing can play an important role in prevention of SARS-CoV-2 transmission, especially among health-care workers and other high-risk groups, but no single strategy will reduce R below 1 at current levels of population immunity. Immunity passports based on antibody tests or tests for infection face substantial technical, legal, and ethical challenges.

Electronics, 2021

COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has a case-fatality rate of 2–3%, with higher rates among elderly patients and patients with comorbidities. Radiologically, COVID-19 is characterised by multifocal ground-glass opacities, even for patients with mild disease. Clinically, patients with COVID-19 present respiratory symptoms, which are very similar to other respiratory virus infections. Our knowledge regarding the SARS-CoV-2 virus is still very limited. These facts make it vitally important to establish mechanisms that allow to model and predict the evolution of the virus and to analyze the spread of cases under different circumstances. The objective of this article is to present a model developed for the evolution of COVID in the city of Manizales, capital of the Department of Caldas, Colombia, focusing on the methodology used to allow its application to other cases, as well as on the monitoring tools developed for this purpose. ...

2020

The outbreak of the novel coronavirus disease, COVID-19, originating from Wuhan, China in early December, has infected more than 70,000 people in China and other countries and has caused more than 2,000 deaths. As the disease continues to spread, the biomedical society urgently began identifying effective approaches to prevent further outbreaks. Through rigorous epidemiological analysis, we characterized the fast transmission of COVID-19 with a basic reproductive number 5.6 and proved a sole zoonotic source to originate in Wuhan. No changes in transmission have been noted across generations. By evaluating different control strategies through predictive modeling and Monte carlo simulations, a comprehensive quarantine in hospitals and quarantine stations has been found to be the most effective approach. Government action to immediately enforce this quarantine is highly recommended.

Corona virus disease or COVID-19 is an infectious disease whose etiological agent has been identified as a novel corona virus known as Severe Acute Respiratory Syndrome Corona virus 2 (SARS CoV 2). Symptoms of the disease include fever, fatigue, loss of smell and taste, dry cough and breathing difficulties in severe cases. The disease is mainly transmitted through discharge from the nose or mouth when an infectious person coughs or sneezes. In this paper, we used a 5-compartmental model incorporating isolation of positive cases to investigate the effect of mass testing and contact tracing on the transmission of COVID-19. The stability analysis of the model showed that the disease-free equilibrium was asymptotically stable when the basic reproduction number is less than unity. Further we performed the sensitivity analysis of the model. The purpose of the sensitivity analysis was to compare the impact of the mass testing to that of contact tracing with the aim of advising the disease control practitioners on the best strategy to stop community transmission in time of limited resources. The results of this analysis showed that mass testing with case isolation had greater impact on community transmission as compared to contact tracing. These results were validated by the use of the numerical simulation of the model. As the number of cases continue to surge and the health facilities get overwhelmed therefore, the health control practitioners need to adopt a control strategy that has the greatest impact on community transmission. The results obtained in this manuscript showed that mass testing followed by case isolation reduced the value of the basic reproduction number much more than contact tracing and is therefore a better strategy in combating community transmission of the disease.

Journal of Physics A: Mathematical and Theoretical

We employ individual-based Monte Carlo computer simulations of a stochastic SEIR model variant on a two-dimensional Newman–Watts small-world network to investigate the control of epidemic outbreaks through periodic testing and isolation of infectious individuals, and subsequent quarantine of their immediate contacts. Using disease parameters informed by the COVID-19 pandemic, we investigate the effects of various crucial mitigation features on the epidemic spreading: fraction of the infectious population that is identifiable through the tests; testing frequency; time delay between testing and isolation of positively tested individuals; and the further time delay until quarantining their contacts as well as the quarantine duration. We thus determine the required ranges for these intervention parameters to yield effective control of the disease through both considerable delaying the epidemic peak and massively reducing the total number of sustained infections.

International Journal of Environmental Research and Public Health

The conversion rate between asymptomatic infections and reported/unreported symptomatic infections is a very sensitive parameter for model variables that spread COVID-19. This is important information for follow-up use in screening, prediction, prognostics, contact tracing, and drug development for the COVID-19 pandemic. The model described here suggests that there may not be enough researchers to solve all of these problems thoroughly and effectively, and it requires careful selection of what we are doing and rapid sharing of results and models and optimizing modeling simulations with value to reduce the impact of COVID-19. Exploring simulation modeling will help decision makers make the most informed decisions. In order to fight against the “Delta” virus, the establishment of a line of defense through all-people testing (APT) is not only an effective method summarized from past experience but also one of the best means to effectively cut the chain of epidemic transmission. The eff...

Infectious Disease Modelling, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 The Authors. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Chiang Mai University Journal of Natural Sciences, 2022

This study aimed to design and test a COVID-19 surveillance system model for community-industry population. A prospective cohort study was conducted from May to December, 2020. Researchers designed a COVID-19 surveillance system and presented it to stakeholders from the community-industry setting in Lamphun and Chiang Mai provinces, Thailand. The model was adjusted following feedback and tested. The model was an Active surveillance for early Alert and rapid Action using Big data and mobile phone application technology for a Community-industry setting (3ABC model). The major components were active surveillance, community-based surveillance, event-based surveillance, and early warning and rapid response. A drive-thru testing unit was operated to enable early detection. Alerts and recommended action on individual and administrative levels were sent via an application and networks. In the testing of the model, risk assessment was initially conducted with regard to COVID-19 transmission ...

International Journal of Research in Pharmaceutical Sciences, 2020

Coronavirus is an RNA virus, positive stranded, and enveloped was first isolated in 1965, can cause symptoms like common cold, severe respiratory symptoms, gastrointestinal, liver and CNS symptoms. WHO announced the original name of coronavirus as COVID 19 in December 2019. This virus has been named as Severe Acute Respiratory Syndrome cov 2 currently and WHO has now declared this virus as emergency of public health concern. More than seventy thousand people in China and 25 other countries have been infected. The confirmed cases of Covid 19 Infection, up to 14th April, 2020 in India were 11,487 and out of which 393 have been deceased and most number of cases were found to be confirmed in Maharashtra (2,684). Animals like camels, cattles, cats, bats probably serve as hosts for coronavirus. Various laboratory investigations like CBC, Real Time-PCR, D-dimer levels, cell culture, electron microscopy, Low platelet count, ESR, CRP levels, Chest CT, X ray, Liver and Kidney Function tests,...

Advances in Multidisciplinary and Scientific Research Journal, 2022

As the world observes a new pandemic with COVID-19, it is clear that pathogens can spread rapidly and without recognition of borders. Outbreaks will continue to occur, and so the diseases' transmission method must be thoroughly understood in order to minimize their impact. Some infections, such as influenza, tuberculosis and measles, known to spread through droplets in the air. In a confined space, the concentration can grow as more droplets released. This study examined a simulated confined space modelled as a hospital waiting area, where people who could have underlying conditions congregate and mix with potentially infectious individuals. It further investigated the impact of the volume of the waiting area, the number of people in the room, the placement of them as well as their weight. The simulation is an agent-based model (ABM), a computational model with the purpose of analyzing a system through the actions and cumulative consequences of autonomous agents. The presented ABM features embodied agents with differing body weights that can move, breathe and cough in a ventilated room. An investigation into current epidemiological models lead to the hypothesis that one may implement as a corresponding ABM, where it could possibly, also be improved upon. In this paper, it has shown that, all parameters of the Gammaitoni and Nucci model, been taken into account, in an ABM via the MASON library. In addition, proof produced, suggested that some flaws of the epidemiological model, should be amended in the ABM. It was demonstrated, the constructed model, account for proximity between susceptible people and infectors, an expressed limitation of the original model.