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BackgroundVariants of the SARS-CoV-2 virus carry differential risks to public health. The Omicron (B.1.1.529) variant, first identified in Botswana on November 11, 2021, has spread globally faster than any previous variant of concern. Understanding the transmissibility of Omicron is vital in the development of public health policy.ObjectiveThe aim of this study is to compare SARS-CoV-2 outbreaks driven by Omicron to those driven by prior variants of concern in terms of both the speed and magnitude of an outbreak.MethodsWe analyzed trends in outbreaks by variant of concern with validated surveillance metrics in several southern African countries. The region offers an ideal setting for a natural experiment given that most outbreaks thus far have been driven primarily by a single variant at a time. With a daily longitudinal data set of new infections, total vaccinations, and cumulative infections in countries in sub-Saharan Africa, we estimated how the emergence of Omicron has altered the trajectory of SARS-CoV-2 outbreaks. We used the Arellano-Bond method to estimate regression coefficients from a dynamic panel model, in which new infections are a function of infections yesterday and last week. We controlled for vaccinations and prior infections in the population. To test whether Omicron has changed the average trajectory of a SARS-CoV-2 outbreak, we included an interaction between an indicator variable for the emergence of Omicron and lagged infections.ResultsThe observed Omicron outbreaks in this study reach the outbreak threshold within 5-10 days after first detection, whereas other variants of concern have taken at least 14 days and up to as many as 35 days. The Omicron outbreaks also reach peak rates of new cases that are roughly 1.5-2 times those of prior variants of concern. Dynamic panel regression estimates confirm Omicron has created a statistically significant shift in viral spread.ConclusionsThe transmissibility of Omicron is markedly higher than prior variants of concern. At the population level, the Omicron outbreaks occurred more quickly and with larger magnitude, despite substantial increases in vaccinations and prior infections, which should have otherwise reduced susceptibility to new infections. Unless public health policies are substantially altered, Omicron outbreaks in other countries are likely to occur with little warning.  相似文献   
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Background: Metabolic syndrome (MS) is a condition that consists of several disorders, and the individual impact of these disorders on metabolic dysfunction-associated fatty liver disease (MAFLD) is still not clear in a combined diagnosis of MS. In this study, we aimed to investigate the effect of MS on advanced fibrosis in patients with MAFLD.Methods: We recruited the patients from our gastroenterology out-patient clinic who were being followed up for MAFLD. MAFLD was diagnosed with liver biopsy in all patients. The frequency of MS and other metabolic parameters were also compared between groups with advanced fibrosis and groups in which fibrosis was not as advanced.Results: In total, we enrolled 424 biopsy-proven MAFLD patients to the study. In univariate analysis, individuals with greater age, body mass index (BMI), higher aspartate transaminase (AST), MS, impaired fasting glucose, hypertension, enlarged waist circumference (WC), diabetes mellitus (DM), and women had significantly increased risk for fibrosis. In multivariate analysis, it was found that DM, greater age, higher BMI, and increased AST were seen more commonly in MAFLD patients with advanced fibrosisConclusion: Greater age, a higher BMI, higher AST and a diagnosis of diabetes were more commonly associated with advanced fibrosis. However, DM was found to be the strongest predictive factor of advanced fibrosis in our cohort (OR: 2.495). Multivariate analyses did not indicate a significantly common occurrence of MS in the advanced fibrosis group, despite its important role in MAFLD pathophysiology.  相似文献   
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Surgical considerations in patients with lumbar spinal root anomalies.   总被引:3,自引:0,他引:3  
Lumbosacral nerve root anomalies are rare and can cause diagnostic confusion. In this report we present 12 patients with lumbar root anomalies. Emphasis is placed on preoperative neuroradiological evaluation and the surgical implications of these anomalies.  相似文献   
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