At the beginning of a COVID-19 infection, there is a period of time known as the exposed or latency period, before an infected person is capable of transmitting the infection to another person. We develop two differential equations models to account for this period. The first is a model that incorporates infected persons in the exposed class, before transmission is possible. The second is a model that incorporates a time delay in infected persons, before transmission is possible. We apply both models to the COVID-19 epidemic in China. We estimate the epidemiological parameters in the models, such as the transmission rate and the basic reproductive number, using data of reported cases. We thus evaluate the role of the exposed or latency period in the dynamics of a COVID-19 epidemic.
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http://dx.doi.org/10.1016/j.idm.2020.03.003 | DOI Listing |
Am J Trop Med Hyg
January 2025
Department of Intensive Care, Amsterdam University Medical Center, Amsterdam, The Netherlands.
Epidemiology, ventilator management, and outcomes in patients with acute respiratory distress syndrome (ARDS) because of coronavirus disease 2019 (COVID-19) have been described extensively but have never been compared between countries. We performed an individual patient data analysis of four observational studies to compare epidemiology, ventilator management, and outcomes. We used propensity score weighting to control for confounding factors.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Epidemiology and Biostatistics, School of Public Health, University at Albany, State University of New York, Rensselaer, New York, United States of America.
Since the emergence of the SARS-CoV-2 virus, research into the existence, extent, and pattern of seasonality has been of the highest importance for public health preparation. This study uses a novel bandpass bootstrap approach called the Variable Bandpass Periodic Block Bootstrap to investigate the periodically correlated components including seasonality within US COVID-19 mortality. Bootstrapping to produce confidence intervals for periodic characteristics such as the seasonal mean requires preservation of the periodically correlated component's correlation structure during resampling.
View Article and Find Full Text PDFPLoS One
January 2025
Sydney Medical School, University of Sydney, Sydney, New South Wales (NSW), Australia.
Acute respiratory infections cause significant paediatric morbidity, but for pathogens other than influenza, respiratory syncytial virus (RSV), and SARS-CoV-2, systematic monitoring is not commonly performed. This retrospective analysis of six years of routinely collected respiratory pathogen multiplex PCR testing at a major paediatric hospital in New South Wales Australia, describes the epidemiology, year-round seasonality, and co-detection patterns of 15 viral respiratory pathogens. 32,599 respiratory samples from children aged under 16 years were analysed.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, United States of America.
Determining COVID-19 vaccination strategies presents many challenges in light of limited vaccination capacity and the heterogeneity of affected communities. Who should be prioritized for early vaccination when different groups manifest different levels of risks and contact rates? Answering such questions often becomes computationally intractable given that network size can exceed millions. We obtain a framework to compute the optimal vaccination strategy within seconds to minutes from among all strategies, including highly dynamic ones that adjust vaccine allocation as often as required, and even with modest computation resources.
View Article and Find Full Text PDFJ Am Coll Health
January 2025
Department of Epidemiology, Columbia University Mailman School of Public Health, New York City, New York, USA.
We aimed to investigate the association between exposure settings and secondary SARS-CoV-2 transmission among university students. Students diagnosed with COVID-19 ( = 139) and randomly selected controls ( = 262) identified between April 4-December 5, 2021. This was a 1:2 case-control study.
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