• Journal of applied mathematics & informatics
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• v.40 no.3_4
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• pp.633-656
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• 2022

Many regions of the world are now facing the second wave of boomed cases of COVID-19. This time, the second wave of this highly infectious disease (COVID-19) is becoming more devastating. To control the existing situation, more mass testing, and tracing of COVID-19 positive individuals are required. Furthermore, practicing to wear a face mask and maintenance of physical distancing are strongly recommended for everyone. Taking all these into consideration, an optimal control problem has been reformulated in terms of nonlinear ordinary differential equations in this paper. The aim of this study is to explore the control strategy of coronavirus-2 disease (COVID-19) and thus, minimize the number of symptomatic, asymptomatic and infected individuals as well as cost of the controls measures. The optimal control model has been analyzed analytically with the help of the necessary conditions of very well-known Pontryagin's maximum principle. Numerical simulations of the optimal control problem are also performed to illustrate the results.

• Journal of Internet Computing and Services
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• v.22 no.1
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• pp.65-77
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• 2021

COVID-19 has recently impacted the world with the large numbers of infected and deaths. The development of effective COVID-19 vaccine has not been successful. Hence, people have a high concern on the infection of this disease. The infection information from the governmantal public organizations are mainly based on simple summary statistics. Consequently, it is hard to assess the infection risks of individual person and the current location of the person. In this paper, we present a machine learning-based software system that analyzes COVID-19 infection risks and guidelines for safe activities.This paper proposes a suite of risk factors regarding COVID-19 infection and deaths and methods to quantitatively measure the individual and group risks using the proposed metrics. The proposed system utilizes a clustering algorithms and various software approaches that reflect the information and features of inviduals and their geograpical locations.

• Pediatric Infection and Vaccine
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• v.30 no.3
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• pp.180-187
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• 2023

In Korea, >90% of children and adolescents aged <19 years have been infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) since 2020. Among confirmed cases of pediatric coronavirus disease 2019 (COVID-19), 40-60% of patients developed neurologic symptoms such as seizures, headache, and encephalitis. Herein, we report the case of a 3-year-old female patient with SARS-CoV-2 infection who presented with seizures and altered consciousness and was diagnosed with COVID-19 encephalitis. The patient recovered after treatment with intravenous immunoglobulin, high-dose steroids, anti-seizure drugs, and an anti-viral agent. She was discharged after regaining the ability to speak words and walk alone on hospital day 39. Complete recovery was observed at the 1-year follow-up. The findings in this case suggest that early detection and active intervention is associated with better outcomes in patients with COVID-19 encephalitis.

• Journal of the Korean Society of Radiology
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• v.84 no.4
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• pp.964-969
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• 2023

Guillain-Barré syndrome (GBS) is an immune-mediated demyelinating polyneuropathy characterized by progressive, ascending, and symmetrical paralysis. It is known to be triggered by an antecedent infection or vaccination. Recently, GBS development following coronavirus disease 2019 (COVID-19) vaccination has been reported. Cranial neuropathies in typical GBS patients usually involve the facial and the lower cranial nerves (from IX to XII). We report a rare case of multiple cranial neuropathies involving trigeminal, abducens, and facial nerves in a patient who developed GBS following COVID-19 vaccination on the basis of obvious MRI features.

• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.57-65
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• 2021

School closures during the coronavirus disease 2019 (COVID-19) pandemic have been outlined in studies from different disciplines, including economics, sociology, mathematical modeling, epidemiology, and public health. In this review, we discuss the implications of school closures in the context of the current COVID-19 pandemic. Modeling studies of the effects of school closures, largely derived from the pandemic influenza model, on severe acute respiratory syndrome coronavirus 2 produced conflicting results. Earlier studies assessed the risk of school reopening by modeling transmission across schools and communities; however, it remains unclear whether the risk is due to increased transmission in adults or children. The empirical findings of the impact of school closures on COVID-19 outbreaks suggest no clear effect, likely because of heterogeneity in community infection pressure, differences in school closure strategies, or the use of multiple interventions. The benefits of school closings are unclear and not readily quantifiable; however, they must be weighed against the potential high social costs, which can also negatively affect the health of this generation.

• Journal of Information Technology Services
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• v.20 no.6
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• pp.45-62
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• 2021

After the COVID-19 outbreak in 2019, the spread of COVID-19 has not been easily caught despite preventive measures in each country. The spread of COVID-19 has hit the world, especially in the economic and tourism sectors. Countries around the world are easing restrictions on the movement of vaccinated people in preparation for the post-corona era. Under the name of "Vaccine Passport," "Vaccination Certificate," and "Digital Health Pass," vaccination measures are being implemented to allow vaccination recipients to use multi-use facilities. However, there is no international agreement on the movement of countries, and each country has its own immigration policy. In order to return to pre-corona daily life, global agreements must be reached from the movement of vaccinated people between countries, and standards and implementation methods must be determined. This study focuses on the implementation and utilization of vaccination certificates suitable for the COVID-19 era. We will look at the spread of COVID-19 and its international response policies. In the case of COVID-19, we will investigate why vaccination certificate installation should be standardized and how far the current standardization has been discussed, and discuss the characteristics of vaccination certificate installation and considerations. In order for the immunization certificate discussed in the previous chapter to be recognized internationally, institutional and technical considerations are identified and security factors that may occur in each implementation are also presented. Finally, the international recognition case of vaccination certificate is discussed, and the method of installation and utilization of vaccination certificate is proposed. This paper can be used as a policy because of its timeliness in studying the standards of vaccination certificates and considerations for international recognition to restore movement between countries in the spread of COVID-19. In addition, if other infectious diseases occur in the future or similar cases where movement between countries is restricted, it can be used as a reference to support the movement of verified people.

• Korean Circulation Journal
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• v.53 no.2
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• pp.109-111
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• 2023

• Journal of Microbiology and Biotechnology
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• v.30 no.3
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• pp.313-324
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• 2020

Coronavirus disease 2019 (COVID-19), which causes serious respiratory illness such as pneumonia and lung failure, was first reported in Wuhan, the capital of Hubei, China. The etiological agent of COVID-19 has been confirmed as a novel coronavirus, now known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is most likely originated from zoonotic coronaviruses, like SARS-CoV, which emerged in 2002. Within a few months of the first report, SARS-CoV-2 had spread across China and worldwide, reaching a pandemic level. As COVID-19 has triggered enormous human casualties and serious economic loss posing global threat, an understanding of the ongoing situation and the development of strategies to contain the virus's spread are urgently needed. Currently, various diagnostic kits to test for COVID-19 are available and several repurposing therapeutics for COVID-19 have shown to be clinically effective. In addition, global institutions and companies have begun to develop vaccines for the prevention of COVID-19. Here, we review the current status of epidemiology, diagnosis, treatment, and vaccine development for COVID-19.

• Pediatric Infection and Vaccine
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• v.29 no.1
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• pp.16-27
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• 2022

In Korea, children aged 5 to 11 have been vaccinated against coronavirus disease 2019 (COVID-19) from March 2022. Due to this age group not being at a high risk of developing severe COVID-19 symptoms, each major country has different, circumstance dependent, immunization policies for children. In this review, the COVID-19 vaccination policies for 5-11 years old children in major countries were reviewed and considerations were presented for Korea, where children 5-11 years old are starting to get vaccinated against COVID-19.

• Journal of Sasang Constitutional Medicine
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• v.35 no.1
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• pp.46-55
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• 2023

Objectives The purpose of this case study was to report a case of anorexia and fatigue after getting vaccinated COVID-19 treated based on Sasang Constitutional Medicine. Methods The patient was hospitalized for 4 days and treated with herbal medicine and moxibustion. The patient was asked to score for daily energy level out of 100 on his own and we used Karnofsky Performance Score(Karnofsky PS) on daily health status to evaluate the clinical effects. We also checked daily amount of meal and evaluated original symptoms such as insomnia, gastric discomfort, bowel movement and dysuria in four stages. Results At initial, the patient could only eat one spoon of a meal and was unable to carry on herself without any assistance, so she used a wheelchair on the day of admission. When discharged, the patient can eat half of a meal at each mealtime and perform normal activities by herself. Discussion This case demonstrates that Sasang constitutional approach to anorexia and fatigue caused by COVID-19 vaccination can be an useful treatment.