ABSTRACT
Coronavirus (COVID-19 or SARS-CoV-2) spreads rapidly around the world. Coronavirus reached 8,000 cases on Jan 30, 2020. When the cases that lost their lives were examined, the majority of them were found to be elderly patients or patients diagnosed with chronic heart, lung and kidney, Parkinson's, and Diabetes. The number of cases worldwide was 509,164, the number of deaths worldwide was 23,335 while analyzing this study. COVID-19 also affected many economic variables in the world. Some of these variables are stock indices. In this study, it is aimed to discover the causal relationship between stock indices and coronavirus. Daily data were used in the research. Stock indices and total deaths and total cases of coronavirus are matched for each country. Unit root tests, Pairwise Granger Causality Tests, and regression analysis were made. The stationarity and level of significance were calculated. Causality Tests used to test hypotheses regarding the presence and the direction of causality. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
ABSTRACT
Bubbles in asset prices have attracted the attention of economists for centuries. Extreme increases in asset prices, followed by their sudden decline, create a turbulent effect on the economy and even invite crises in time. For this reason, some measurement techniques have been employed to investigate the price bubbles that may occur. This study explores the possible speculative price bubbles of Bitcoin, Ethereum, and Binance Coin cryptocurrencies, compares them with the pre-and post-COVID-19 period, and examines asymmetric causality relationships between variables. Therefore, we analyzed the price bubbles of these cryptocurrencies using the closing price for daily data between 16.01.2018 and 31.12.2021 by the Supremum Augmented Dickey-Fuller (SADF) and the Hatemi-J (2012) asymmetric causality test. In this context, 1446 observations, 723 of which were before COVID-19 and 723 after COVID-19, were employed in the study. Looking at the SADF analysis results, we detected 103 price bubbles before COVID-19 for the three cryptocurrencies, while we determined 599 price bubbles after COVID-19. The common finding in the asymmetric causality test results is that there is a causality relationship between the negative shocks faced by one cryptocurrency and the positive shocks faced by the other cryptocurrencies.
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The Covid-19 crisis initiated debates among sociologists concerning metatheoretical principles of sociology and how sociological analyses should be done in times of pandemic. We discuss the methodological basis of the explanatory sociology approach and demonstrate its relevance in times of pandemic. We start with the paradigm of realism and then proceed to the guiding principles of causality and methodological individualism. It is argued that this is the appropriate and reasonable epistemological basis for sociology and enables explanation of social phenomena as well as prediction of unintended consequences of social interventions associated with the Covid-19 crisis. We state that this sort of sociology now is disputed neither within the scientific community nor outside in the media and the general society, although this had been the case constantly before the pandemic. © The Author(s), under exclusive license to Springer Fachmedien Wiesbaden GmbH, part of Springer Nature 2021.
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This paper analyzes the causal relationship between the Brazilian stock market indicator and other stock exchange indicators. Specifically, the study time incorporates the world crisis caused by the covid-19 and the war over the price of oil. Were used the differentiated series considering the existence of a unit root, the VAR and Granger Causality models were subsequently estimated. The results show that the causality between the Ibovespa with the S&P500 and Nikkei is bidirectional. These results are consistent when relating the degree of commercial exchange and the origin of foreign investment in Brazil. © 2023, Cuadernos de Economia (Colombia). All Rights Reserved.
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This study examined the global systemic risk network connectedness during the COVID-19 pandemic by focusing on the stock, bond, and foreign exchange markets of 14 countries (2000–2021). We found that the commonality among multiple markets was high, while the systemic risk of COVID-19 was smaller than that of the 2007–2008 financial crisis. Additionally, the exposure of bond markets to systemic risk was larger than the exchange rate and stock markets. Although the stock and bond markets were the main sources of risk during the pandemic, the foreign exchange market had the strongest connection with the global financial network.
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Background/Aims There are sporadic reports about the development of new rheumatic immune-mediated inflammatory diseases (R-IMIDs) in adults after receiving SARS-CoV-2 vaccines. This systematic review (SR) aimed to critically review and summarize the clinical profile, patient demographics, treatment, and prognosis of new-onset R-IMIDs following SARS-CoV-2 vaccination. Methods We retrieved English-language articles (Case reports and series and observational studies) on new-onset R-IMIDs following SARS-CoV-2 vaccination, published until June 2022, from standard databases (MEDLINE, Embase, Cochrane). The search strings used during the literature search incorporated 'SARS-CoV-2 vaccination' (along with related MeSH terms) and various key terms for R-IMIDs [which included (but was not limited to) inflammatory arthritis, connective tissue disease (CTD), vasculitis, systemic lupus erythematosus, Sjogren's syndrome, sarcoidosis, systemic sclerosis, idiopathic inflammatory myositis, anti-synthetase syndrome, Adult-onset Stills disease (AOSD), giant cell arteritis (GCA), and polymyalgia rheumatica (PMR)]. The protocol was registered in PROSPERO (CRD42022318561). Results Of the total 2179 articles retrieved, 1986 articles were excluded following the title- screening, and 107 articles that did not meet inclusion criteria. We included the remaining 86 articles (130 cases) upon full-text screening. Furthermore, we added four articles (six cases) based on a manual search, comprising 90 articles (136 cases) for final analysis. These 136 new R-IMID cases were reported from 27 different countries. Of these, more than one-third of the cases were reported from three countries (viz., Italy, Japan, and the USA). The patients had a mean age of 57 (range:17-90) years, and the majority were females (63.0%). Most patients developed R-IMIDs after receiving Pfizer-BioNTech vaccine (76;55%), followed by Oxford AstraZeneca vaccine (35;25%). The mean duration between SARSCoV- 2 vaccination and R-IMIDs development was 9.2 (range:1-90) days. The second dose of the vaccine resulted in more R-IMIDs (74;54%) than the first (53;39%). CTDs (34;25%) and small vessel vasculitis (33;24%) were the commonest R-IMID manifestations, followed by inflammatory arthritis and AOSD, each in 13 (9.5%) cases. Nearly half of the patients with CTDs had Idiopathic Inflammatory Myositis. PMR and GCA accounted for 16 (11.7%) and 5 (3.6%) cases, respectively. However, no cases of axial spondylarthritis were reported. Most (118;86%) R-IMID patients were treated with corticosteroids, with a small number receiving steroid-sparing drugs, such as methotrexate, rituximab and cyclophosphamide. Most (125;91%) went into either disease remission or improvement following the treatment. Only three patients were admitted to the intensive care unit (ICU) to manage their disease;One of them died due to fatal myositis and rhabdomyolysis;two surviving ICU patients had ANCA-associated vasculitis with lung involvement. Conclusion Although rare, this SR highlights the emergence of de novo R-IMIDs following SARS-CoV-2 vaccination. We cannot confirm the causality between the vaccination and the onset of R-IMID. However, further research is warranted in this area.
ABSTRACT
Molecular mimicry between foreign and self-antigens has been implicated as a cause of autoimmune hepatitis in experimental models and cross-reacting antibodies in patients. This review describes the experimental and clinical evidence for molecular mimicry as a cause of autoimmune hepatitis, indicates the limitations and uncertainties of this premise, and encourages investigations that assess diverse environmental antigens as sources of disease-relevant molecular mimics. Pertinent articles were identified in PubMed using multiple search phrases. Several pathogens have linear or conformational epitopes that mimic the self-antigens of autoimmune hepatitis. The occurrence of an acute immune-mediated hepatitis after vaccination for severe acute respiratory syndrome (SARS)-associated coronavirus 2 (SARS-CoV-2) has suggested that vaccine-induced peptides may mimic disease-relevant tissue antigens. The intestinal microbiome is an under-evaluated source of gut-derived antigens that could also engage in molecular mimicry. Chaperone molecules may enhance the pathogenicity of molecular mimics, and they warrant investigation. Molecular mimics of immune dominant epitopes within cytochrome P450 IID6, the autoantigen most closely associated with autoimmune hepatitis, should be sought in diverse environmental antigens and assessed for pathogenicity. Avoidance strategies, dietary adjustments, vaccine improvement, and targeted manipulation of the intestinal microbiota may emerge as therapeutic possibilities. In conclusion, molecular mimicry may be a missing causality of autoimmune hepatitis. Molecular mimics of key immune dominant epitopes of disease-specific antigens must be sought in diverse environmental antigens. The ubiquity of molecular mimicry compels rigorous assessments of peptide mimics for immunogenicity and pathogenicity in experimental models. Molecular mimicry may complement epigenetic modifications as causative mechanisms of autoimmune hepatitis.