COVID-19 illness and autoimmune diseases: recent insights.

BACKGROUND: The aim of this review is to explore whether patients with autoimmune diseases (AIDs) were at high risk of infection during the COVID-19 epidemic and how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic affected immune system. METHODS: A systematic literature search was performed using the foreign databases (NCBI, web of science, EBSCO, ELSEVIER ScienceDirect) and Chinese databases (WanFang, CNKI (China National Knowledge Infrastructure), VIP, CBM) to locate all relevant publications (up to January 10, 2021). The search strategies used Medical Search Headings (MeSH) headings and keywords for "COVID-19" or "SARS-CoV-2" or "coronavirus" and "autoimmune disease". RESULTS: This review evaluates the effect of SARS-CoV-2 on the immune system through ACE-2 receptor binding as the main pathway for cell attachment and invasion. It is speculated that SARS-COV-2 infection can activate lymphocytes and inflammatory response, which may play a role in the clinical onset of AIDs and also patients were treated with immunomodulatory drugs during COVID-19 outbreak. Preliminary studies suggested that the risk of developing severe forms of COVID-19 in patients with AIDs treated with immunomodulators or biologics might not increase. A large number of samples are needed for further verification, leading to an excessive immune response to external stimuli. CONCLUSION: The relationship between autoimmune diseases and SARS-CoV-2 infection is complex. During the COVID-19 epidemic, individualized interventions for AIDs should be provided such as Internet-based service.

COVID-19 and instability of stock market performance: evidence from the U.S.

The effect of COVID-19 on stock market performance has important implications for both financial theory and practice. This paper examines the relationship between COVID-19 and the instability of both stock return predictability and price volatility in the U.S over the period January 1st, 2019 to June 30th, 2020 by using the methodologies of Bai and Perron (Econometrica 66:47-78, 1998. 10.2307/2998540; J Appl Econo 18:1-22, 2003. 10.1002/jae.659), Elliot and Muller (Optimal testing general breaking processes in linear time series models. University of California at San Diego Economic Working Paper, 2004), and Xu (J Econ 173:126-142, 2013. 10.1016/j.jeconom.2012.11.001). The results highlight a single break in return predictability and price volatility of both S&P 500 and DJIA. The timing of the break is consistent with the COVID-19 outbreak, or more specifically the stock selling-offs by the U.S. senate committee members before COVID-19 crashed the market. Furthermore, return predictability and price volatility significantly increased following the derived break. The findings suggest that the pandemic crisis was associated with market inefficiency, creating profitable opportunities for traders and speculators. Furthermore, it also induced income and wealth inequality between market participants with plenty of liquidity at hand and those short of funds.

Chest radiography to assess and prognosticate COVID-19 (preprint)

Background To determine the utility of chest radiography (CXR) for assessing and prognosticating COVID-19 disease with an objective radiographic scoring system.Methods A multicenter, prospective study was conducted, forty patients were included. Seventy-eight CXR’s were performed on the first derivation cohort of twenty patients with COVID-19 (median age 47.5 years, 10 females and four with comorbidities) admitted between 22 January 2020 and 1 February 2020. Each CXR was scored by three radiologists in consensus and graded on a 72-point COVID-19 Radiographic Score (CRS). This was correlated with supplemental oxygen requirement, C-reactive protein (CRP), lactate dehydrogenase (LDH) and lymphocyte count. To validate our findings, the parameters of another validation cohort of twenty patients with 65 CXRs were analysed.Results In the derivation cohort, seven patients needed supplemental oxygen and one was intubated for mechanical ventilation with no death. The maximum CRS was significantly different between patients on and not on supplemental oxygen (p=<.001). There was strong correlation between maximum CRS and lowest oxygen saturation (r= -.849), maximum CRP (r= .832) and maximum LDH (r= .873). These findings were consistent in the validation cohort. An increment of 2 points in CRS had an accuracy of 0.938 with 100.0% sensitivity (95% CI 100.0-100.0) and 83.3% (95% CI 65.1-100.0) specificity in predicting supplemental oxygen requirement.Conclusion Using an objective scoring system (CRS), the degree of abnormalities on CXR correlates closely with known markers of disease severity. CRS may further be applied to predict patients who require oxygen supplementation during the course of their disease.