Evaluation of the effect of vaccination on transmissibility and pathogenicity of Omicron variant and its comparison with other SARS-CoV-2 variants

The new variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has once again sounded the alarm on healthcare systems worldwide and has caused concern in some countries. This variant has been identified in South Africa and initially called B.1.1.529 and later renamed Omicron by the WHO. The transmissibility and immune evasion in the Omicron variant (B.1.1.529) is higher than the previous variants. Compared to the previous dominant variant, which was called the Delta variant, the Omicron variant has a very high transmission power but luckily, Omicron's symptoms are less serious. According to the WHO, the Omicron variant has the potential to re-infect people who already have other variants of SARS-CoV-2. Omicron contains at least 32 mutations in the spike protein also other proteins that are required for viral replication and it is twice the size of delta variant. Half of the mutations in this variant occur in the area of the virus through which they bind to the cells of the human body and cause infection. The Omicron variant likely developed in one person during chronic infection with an immune system deficiency (possibly untreated HIV/AIDS). It is possible that injecting a booster dose of existing vaccines and subsequently increasing antibody levels will provide adequate protection and an appropriate barrier against Omicron. The purpose of this article is to evaluate the Omicron variant and compare it with other SARS-CoV-2 variants and the effect of a booster dose in preventing disease progression

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed