ABSTRACT
COVID-19 has been impacting stock markets worldwide. Yet, a scant amount of research has been done on the stock markets of the Gulf Cooperation Council (GCC) markets. In this work, we aim to investigate whether and to what extent local and international events linked to the COVID-19 outbreak have impacted stock market volatility of the GCC countries. We model stocks' returns of these countries between January and December 2020, decomposing the errors' heteroskedasticity to account for main international and local events related to COVID-19. These events have been included as structural breaks and measured using dichotomous variables. Both local and international events were found to be associated with significant variations in volatility;however, local events seem to have impacted volatility to a lesser extent compared to international events. The announcement of the status of pandemic by the WHO had the greatest impact on volatility across the GCC markets, even greater than the impact associated to the drop in oil prices. The announcement of local approval of vaccine led to a reduction in volatility in UAE (ADX), Qatar, Saudi Arabia and Bahrain © International Journal of Economics and Management
ABSTRACT
The COVID-19 pandemic has resulted in significant morbidity, mortality, and strained healthcare systems worldwide. Thus, a search for modalities that can expedite and improve the diagnosis and management of this entity is underway. Recent data suggested the utility of lung ultrasound (LUS) in the diagnosis of COVID-19 by detecting an interstitial pattern (B-pattern). Hence, we aimed to pool the proportion of various reported lung abnormalities detected by LUS in symptomatic COVID-19 patients. We conducted a systematic review (PubMed, MEDLINE, and EMBASE until April 25, 2020) and a proportion meta-analysis. We included seven studies examining the role of LUS in 122 COVID-19 patients. The pooled proportion (PP) of B-pattern detected by lung ultrasound (US) was 0.97 (95% CI: 0.94-1.00 I 2 0%, Q 4.6). The PP of finding pleural line abnormalities was 0.70 (95% CI: 0.13-1.00 I 2 96%, Q 103.9), of pleural thickening was 0.54 (95% 0.11-0.95 I 2 93%, Q 61.1), of subpleural or pulmonary consolidation was 0.39 (95% CI: 0.21-0.58 I 2 72%, Q 17.8), and of pleural effusion was 0.14 (95% CI: 0.00-0.37 I 2 93%, Q 27.3). Our meta-analysis revealed that almost all SARS-CoV-2-infected patients have abnormal lung US. The most common abnormality is interstitial involvement depicted as B-pattern. The finding from our review highlights the potential role of this modality in the triage, diagnosis, and follow-up of COVID-19 patients. A sizable diagnostic accuracy study comparing LUS, computed tomography scan, and COVID-19-specific tests is warranted to further test this finding and to delineate the diagnostic and prognostic yield of each of these modalities.