{"title":"Phenomenological Models of Three Scenarios of Local SARS-COV-2 Coronavirus Epidemics in New York, Brazil, and Japan","authors":"A. Yu. Perevaryukha","doi":"10.1134/s2070048224700078","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The COVID-19 pandemic did not end in the summer of 2023 but moved into the stage of a dynamic confrontation between a mutating pathogen and herd immunity (natural and vaccine). Pandemic influenza strains were guaranteed to die out after three waves. SARS-COV-2 is able to maintain variability in its E and S proteins. The diversity of SARS-COV-2 strains increases in bursts (XBB.x in India, XBC in the Philippines). Most strains drop out of distribution, but the remaining ones give rise to new branches such as BA.2.86 Pirola and its descendants of the JN.x series, active in the winter wave of 2024. The evolution is reflected by the pulsation in the number of recorded infections, but the frequency and amplitude of the peaks differ in regions. Regional epidemic scenarios are emerging, and some of them are unusual. It is not only the property of the variability of the antigens of the virus that leads to new repeated outbreaks after the attenuation of the oscillations in the number of infections. Regional epidemic scenarios are being formed, some of them are unusual and interesting for modeling. For a phenomenological model description of scenarios for the emergence of new waves, we propose equations with a delay as a flexible tool for analyzing complex forms of oscillatory dynamics. The equations are supplemented with special threshold damping functions. In the models, it is possible to obtain scenarios of both collapsing and damping oscillations with the possibility of a new outbreak, which describes the effect of a single extreme wave after an increase in the length of active infection chains in New York with a sharp J-shaped peak with oscillatory attenuation that stands out sharply among the morbidity oscillations. The wave scenario in Brazil differs significantly from both the primary outbreak in 2020 and the specific epidemic scenario in Japan in 2022–2023 in the form of a series of eight consecutive short peaks with increasing wave amplitude. Since the coronavirus successfully counteracts the immune system, there is an increase in severe cases of reinfection with COVID-19 in a group that is particularly susceptible. An important factor for slowing down the evolution of the virus is heterogeneity of the population immunity, when activated T-lymphocytes and antibodies produced in the population are able to respond to a wide range of epitopes from different conservative regions of proteins. In the spring of 2024 a new strain JN with significantly reduced affinity for the cell receptor spreads.</p>","PeriodicalId":38050,"journal":{"name":"Mathematical Models and Computer Simulations","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mathematical Models and Computer Simulations","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1134/s2070048224700078","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"Mathematics","Score":null,"Total":0}
引用次数: 0
Abstract
The COVID-19 pandemic did not end in the summer of 2023 but moved into the stage of a dynamic confrontation between a mutating pathogen and herd immunity (natural and vaccine). Pandemic influenza strains were guaranteed to die out after three waves. SARS-COV-2 is able to maintain variability in its E and S proteins. The diversity of SARS-COV-2 strains increases in bursts (XBB.x in India, XBC in the Philippines). Most strains drop out of distribution, but the remaining ones give rise to new branches such as BA.2.86 Pirola and its descendants of the JN.x series, active in the winter wave of 2024. The evolution is reflected by the pulsation in the number of recorded infections, but the frequency and amplitude of the peaks differ in regions. Regional epidemic scenarios are emerging, and some of them are unusual. It is not only the property of the variability of the antigens of the virus that leads to new repeated outbreaks after the attenuation of the oscillations in the number of infections. Regional epidemic scenarios are being formed, some of them are unusual and interesting for modeling. For a phenomenological model description of scenarios for the emergence of new waves, we propose equations with a delay as a flexible tool for analyzing complex forms of oscillatory dynamics. The equations are supplemented with special threshold damping functions. In the models, it is possible to obtain scenarios of both collapsing and damping oscillations with the possibility of a new outbreak, which describes the effect of a single extreme wave after an increase in the length of active infection chains in New York with a sharp J-shaped peak with oscillatory attenuation that stands out sharply among the morbidity oscillations. The wave scenario in Brazil differs significantly from both the primary outbreak in 2020 and the specific epidemic scenario in Japan in 2022–2023 in the form of a series of eight consecutive short peaks with increasing wave amplitude. Since the coronavirus successfully counteracts the immune system, there is an increase in severe cases of reinfection with COVID-19 in a group that is particularly susceptible. An important factor for slowing down the evolution of the virus is heterogeneity of the population immunity, when activated T-lymphocytes and antibodies produced in the population are able to respond to a wide range of epitopes from different conservative regions of proteins. In the spring of 2024 a new strain JN with significantly reduced affinity for the cell receptor spreads.
期刊介绍：
Mathematical Models and Computer Simulations is a journal that publishes high-quality and original articles at the forefront of development of mathematical models, numerical methods, computer-assisted studies in science and engineering with the potential for impact across the sciences, and construction of massively parallel codes for supercomputers. The problem-oriented papers are devoted to various problems including industrial mathematics, numerical simulation in multiscale and multiphysics, materials science, chemistry, economics, social, and life sciences.
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