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SARS-CoV-2 evolution has continued to generate variants, responsible for new pandemic waves locally and globally. Varying disease presentation and severity has been ascribed to inherent variant characteristics and vaccine immunity. This study analyzed genomic data from 305 whole genome sequences from SARS-CoV-2 patients before and through the third wave in India. Delta variant was responsible for disease in patients without comorbidity(97%), while Omicron BA.2 caused disease primarily in those with comorbidity(77%). Tissue adaptation studies brought forth higher propensity of Omicron variants to bronchial tissue than lung, contrary to observation in Delta variants from Delhi. Study of codon usage pattern distinguished the prevalent variants, clustering them separately, Omicron BA.2 isolated in February grouped away from December strains, and all BA.2 after December acquired a new mutation S959P in ORF1b (44.3% of BA.2 in the study) indicating ongoing evolution. Loss of critical spike mutations in Omicron BA.2 and gain of immune evasion mutations including G142D, reported in Delta but absent in BA.1, and S371F instead of S371L in BA.1 could possibly be due to evolutionary trade-off and explain very brief period of BA.1 in December 2021, followed by complete replacement by BA.2.
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BackgroundThe second wave of the COVID-19 pandemic hit India from early April 2021 to June 2021 and more than 400,000 cases per day were reported in the country. We describe the clinical features, demography, treatment trends, baseline laboratory parameters of a cohort of patients admitted at the All India Institute of Medical Sciences, New Delhi with SARS-CoV-2 infection and their association with the outcome. MethodsThis was a retrospective cohort study describing the clinical, laboratory and treatment patterns of consecutive patients admitted with SARS-CoV-2 infection. Multivariate logistic regression models were fitted to identify the clinical and biochemical predictors of developing hypoxia, deterioration during the hospital stay and death. FindingsA total of 2080 patients were included in the study. The case fatality rate was 19.5%. Amongst the survivors, the median duration of hospital stay was 8 (5-11) days. Out of 853 (42.3%%) of patients who had COVID-19 Acute respiratory distress syndrome at presentation, 340 (39.9%) died. Patients aged 45-60 years [OR (95% CI): 1.8 (1.2-2.6)p =0.003] and those aged >60 years [OR (95%CI): 3.4 (2.3-5.2), p<0.001] had a higher odds of death as compared to the 18-44 age group. Vaccination reduced the odds of death by 30% [OR (95% CI): 0.7 (0.5-0.9), p=0.036]. Patients with hyper inflammation at baseline as suggested by leucocytosis [OR (95% CI): 2.1 (1.4-3.10), p <0.001], raised d-dimer >500 mg/dL [OR (95% CI): 3.2 (2.2-4.6), p <0.001] and raised C-reactive peptide >0.5 mg/L [OR (95% CI): 3.8 (1.1-13), p=0.037] had higher odds of death. Patients who were admitted in the second week had lower odds of death and those admitted in the third week had higher odds of death. InterpretationThis is the largest cohort of patients admitted with COVID-19 from India reported to date and has shown that vaccination status and early admission during the inflammatory phase can change the course of illness of these patients. Strategies should be made to improve vaccination rates and early admission of patients with moderate and severe COVID-19 to improve outcomes. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSThe COVID-19 pandemic has been ravaging the world since December 2019 and the cases in various regions are being reported in waves. We found that the case fatality rates ranging from 1.4% to 28.3% have been reported in the first wave in India. Older age and the presence of comorbidities are known predictors of mortality. There are no reports regarding the effectiveness of vaccination, correlation of mortality with the timing of admission to the health care facility and inflammatory markers in the second wave of the COVID-19 pandemic in India. Added-value of this studyThis study reports the real-world situation where patients get admitted at varying time points of their illness due to the mismatch between the availability of hospital beds and the rising number of COVID-19 patients during the pandemic. It reports the odds of developing severe hypoxia necessitating oxygen therapy and death thus helping identify priority groups for admission. Implications of all the available evidenceThis study found increased odds of requiring oxygen support or death in patients older than 45 years of age, with comorbidities, and those who had hyper-inflammation with raised C-reactive peptide, d-dimer or leukocytosis. Patients who were admitted in the second week of illness had lower odds of death as compared to those admitted in the third week implying that treatment with corticosteroids in the second week of the illness during the inflammatory phase could lead to reduced mortality. These findings would help triage patients and provide guidance for developing admission policy during times where hospital beds are scarce. Vaccination was found to reduce the odds of deterioration or death and should be fast-tracked to prevent further waves of the pandemic.
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No abstract available.