Current Perspective of COVID-19 on Neurology: A Mechanistic Insight.

SARS-CoV-2, the novel coronavirus and the causative organism of the Covid-19 pandemic wreaked havoc worldwide producing asymptomatic to symptomatic cases leading to significant morbidity and mortality even after infection. Most of the countries reported a mortality rate of 2-3 % majorly due to cardiorespiratory failures. Recent studies highlighted the neurological involvement playing a key role in cardiorespiratory failures and other symptoms such as headache, anosmia, and ageusia observed in Covid-19 patients. Studies suggest SARS-CoV-2 entry via Olfactory Epithelium (OE), and the expression of type 2 transmembrane serine protease (TMPRSS2) in addition to Angiotensin-Converting Enzyme 2 (ACE2) can facilitate SARS-CoV-2 neurotropism. The virus can either travel via peripheral blood vessel causing endothelial dysfunction, triggering coagulation cascade and multiple organ dysfunction or reach the systemic circulation and take a different route to the Blood-Brain Barrier (BBB), disrupting the BBB causing neuroinflammation or neuronal excitotoxicity resulting in the development of encephalitis, encephalopathy, seizures, and strokes. SARS-CoV-2 invasion on the brain stem is believed to be responsible for the cardiorespiratory failures observed in Covid-19 patients. Apart from viral invasion via hematogenous route, SARS-CoV-2 neural invasion via PNS nerve terminal, results in viral replication and retrograde transportation to soma leading to invasion of the CNS including the brain producing neurological manifestations of the disease either in the initial stages or during the course of the disease and even for a long period post-infection in many cases. The ACE2 receptors are expressed in the brain and glial cells and SARS-CoV-2 acts via neuronal as well as nonneuronal pathways. But the exact cell types involved and how they can trigger inflammatory pathways need further in-depth study for the development of targeted therapy.

Adverse events associated with Covishield vaccination among healthcare workers in a tertiary hospital in South India.

Background: Vaccination is the most important prophylactic measure taken to curb COVID-19 pandemics. This study was undertaken to throw light on the safety of Covishield vaccine among health care workers (HCWs) and to assess the co-variates associated with incidence of adverse events. Methods: This prospective observational study was conducted in a tertiary care center in South India as part of the HCW vaccination drive. All consenting HCWs who received the first dose of Covishield vaccine and developed ADRs were included in this study. After vaccination, all beneficiaries were monitored for AEFI for a period of half an hour and later followed up through telephone and google survey forms on day 2 and day 7 of vaccination. The data was subsequently collated into spreadsheet format and analyzed. Results: The study included 1264 consenting healthcare workers who were predominantly youth, aged 15-24 years (n = 583, 46 %) and with a female preponderance of 76 % (n = 960). Past history of COVID-19 infections was reported among 4.6 % (58) of the study population. Postvaccination symptoms were majorly reported during the first (40 %) and second day (44 %) after vaccination with a high prevalence of both local (n = 1083, 85 %) and systemic symptoms (n = 1065, 84 %). The mean duration of symptoms was observed to be 1.4 ± 0.81 days post vaccination. Symptoms were observed significantly high among females (76.7 %, p = 0.013). The prevalence of systemic (88 % vs 80 %) (p < 0.001) and allergic symptoms (7 % vs 3 %; p = 0.03) were observed to be significantly high among respondents with <25 years of age. The systemic and allergic symptoms following vaccination were reported to be low among healthcare workers who had a previous history of COVID-19 infection. Conclusion: COVID vaccination has been observed to be safe and well tolerated with more systemic symptoms reported among younger age group and females.