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1.
Math Biosci Eng ; 19(1): 1026-1040, 2022 01.
Article in English | MEDLINE | ID: covidwho-1560150

ABSTRACT

As of August 2021, COVID-19 is still spreading in Japan. Vaccination, one of the key measures to bring COVID-19 under control, began in February 2021. Previous studies have reported that COVID-19 vaccination reduces the number of infections and mortality rates. However, simulations of spreading infection have suggested that vaccination in Japan is insufficient. Therefore, we developed a susceptible-infected-recovered-vaccination1-vaccination2-death model to verify the effect of the first and second vaccination doses on reducing the number of infected individuals in Japan; this includes an infection simulation. The results confirm that appropriate vaccination measures will sufficiently reduce the number of infected individuals and reduce the mortality rate.


Subject(s)
COVID-19 , COVID-19 Vaccines , Humans , Japan , SARS-CoV-2 , Vaccination
2.
Journal of Advanced Computational Intelligence and Intelligent Informatics ; 25(6):931-943, 2021.
Article in English | ProQuest Central | ID: covidwho-1527067

ABSTRACT

As of Aug. 2020, coronavirus disease 2019 (COVID-19) is still spreading in the world. In Japan, the Ministry of Health, Labour and Welfare developed “COVID-19 Contact-Confirming Application (COCOA),” which was released on June 19, 2020. By utilizing COCOA, users can know whether or not they had contact with infected persons. If those who had contact with infected individuals keep staying at home, they may not infect those outside. However, effectiveness decreasing the number of infected individuals depending on the app’s various usage parameters is not clear. If it is clear, we could set the objective value of the app’s usage parameters (e.g., the usage rate of the total populations) and call for installation of the app. Therefore, we develop a multi-agent simulator that can express COVID-19 spreading and usage of the apps, such as COCOA. In this study, we describe the simulator and the effectiveness of the app in various scenarios. The result obtained in this study supports those of previously conducted studies.

3.
Math Biosci Eng ; 18(5): 6506-6526, 2021 07 28.
Article in English | MEDLINE | ID: covidwho-1390822

ABSTRACT

As of April 2021, the coronavirus disease (COVID-19) continues to spread in Japan. To overcome COVID-19, the Ministry of Health, Labor, and Welfare of the Japanese government developed and released the COVID-19 Contact-Confirming Application (COCOA) on June 19, 2020. COCOA users can know whether they have come into contact with infectors. If persons who receive a contact notification through COCOA undertake self-quarantine, the number of infectors in Japan will decrease. However, the effectiveness of COCOA in reducing the number of infectors depends on the usage rate of COCOA, the rate of fulfillment of contact condition, the rate of undergoing the reverse transcription polymerase chain reaction (RT-PCR) test, the false negative rate of the RT-PCR test, the rate of infection registration, and the self-quarantine rate. Therefore, we developed a Susceptible-Infected-Removed (SIR) model to estimate the effectiveness of COCOA. In this paper, we introduce the SIR model and report the simulation results for different scenarios that were assumed for Japan.


Subject(s)
COVID-19 , Computer Simulation , Humans , Japan , Quarantine , SARS-CoV-2
4.
Infect Dis Ther ; 10(4): 2489-2509, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1375855

ABSTRACT

INTRODUCTION: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), is an enveloped, single-stranded RNA virus. Favipiravir is an orally administrable antiviral drug whose mechanism of action is to selectively inhibit RNA-dependent RNA polymerase. A preliminary trial in COVID-19 patients reported significant improvements across a multitude of clinical parameters, but these findings have not been confirmed in an adequate well-controlled trial. We conducted a randomized, single-blind, placebo-controlled Phase III trial assessing the efficacy and safety of favipiravir in patients with moderate pneumonia not requiring oxygen therapy. METHODS: COVID-19 patients with moderate pneumonia (SpO2 ≥ 94%) within 10 days of onset of fever (temperature ≥ 37.5 °C) were assigned to receive either placebo or favipiravir (1800 mg twice a day on Day 1, followed by 800 mg twice a day for up to 13 days) in a ratio of 1:2. An adaptive design was used to re-estimate the sample size. The primary endpoint was a composite outcome defined as the time to improvement in temperature, oxygen saturation levels (SpO2), and findings on chest imaging, and recovery to SARS-CoV-2-negative. This endpoint was re-examined by the Central Committee under blinded conditions. RESULTS: A total of 156 patients were randomized. The median time of the primary endpoint was 11.9 days in the favipiravir group and 14.7 days in the placebo group, with a significant difference (p = 0.0136). Favipiravir-treated patients with known risk factors such as obesity or coexisting conditions provided better effects. Furthermore, patients with early-onset in the favipiravir group showed higher odds ratio. No deaths were documented. Although adverse events in the favipiravir group were predominantly transient, the incidence was significantly higher. CONCLUSIONS: The results suggested favipiravir may be one of options for moderate COVID-19 pneumonia treatment. However, the risk of adverse events, including hyperuricemia, should be carefully considered. TRIAL REGISTRATION: Clinicaltrials.jp number: JapicCTI-205238.

6.
J Investig Med High Impact Case Rep ; 9: 23247096211029787, 2021.
Article in English | MEDLINE | ID: covidwho-1299320

ABSTRACT

We report the case of a 65-year-old man with COVID-19 (coronavirus disease-2019) post-infectious encephalitis who presented with delirium as an initial manifestation. He had severe COVID-19 pneumonia and recovered with dexamethasone and tocilizumab. One week after discharge, he developed abnormal behavior and delirium without fever and respiratory symptoms. Brain magnetic resonance imaging showed no abnormalities. Cerebrospinal fluid showed pleocytosis and elevated protein concentrations and was negative for severe acute respiratory syndrome-coronavirus-2 RNA. No anti-neuronal autoantibodies against intracellular and neuronal surface proteins were detected. The cerebrospinal fluid inflammatory changes compatible with post-infectious encephalitis, and the patient recovered with intravenous methylprednisolone and intravenous immunoglobulin therapy. Delirium could be an initial symptom of post-infectious encephalitis in older adults with COVID-19, and these patients may require immunosuppressive therapy.


Subject(s)
COVID-19/complications , Delirium/etiology , Encephalitis, Viral/etiology , Aged , Brain/diagnostic imaging , COVID-19/diagnostic imaging , Encephalitis, Viral/diagnostic imaging , Humans , Lung/diagnostic imaging , Magnetic Resonance Imaging , Male , SARS-CoV-2/isolation & purification , Tomography, X-Ray Computed
8.
Respir Investig ; 59(2): 169-179, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-1014780

ABSTRACT

Outbreaks of the novel coronavirus disease (severe acute respiratory syndrome coronavirus 2: SARS-CoV-2) (coronavirus disease 2019; COVID-19) remind us once again of the mechanisms of zoonotic outbreaks. Climate change and the expansion of agricultural lands and infrastructures due to population growth will ultimately reduce or eliminate wildlife and avian habitats and increase opportunities for wildlife and birds to come into contact with livestock and humans. Consequently, infectious pathogens are transmitted from wildlife and birds to livestock and humans, promoting zoonotic diseases. In addition, the spread of diseases has been associated with air pollution and social inequities, such as racial discrimination, gender inequality, and racial, economic, and educational disparities. The COVID-19 pandemic is a fresh reminder of the significance of excessive greenhouse gas excretion and air pollution, highlighting social inequities and distortions. This provides us with an opportunity to reflect on the appropriateness of our trajectory. Therefore, this review glances through the COVID-19 pandemic and discusses our future.


Subject(s)
COVID-19/epidemiology , COVID-19/transmission , Disease Outbreaks , Pandemics , Viral Zoonoses/epidemiology , Viral Zoonoses/transmission , Air Pollution , Animals , Animals, Wild , Ecosystem , Global Warming , Humans , Livestock , Socioeconomic Factors
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