Low-coverage whole genome sequencing for a highly selective cohort of severe COVID-19 patients (preprint)

Despite advances in identifying genetic markers associated to severe COVID-19, the full genetic characterisation of the disease remains elusive. This study explores the use of imputation in low-coverage whole genome sequencing for a severe COVID-19 patient cohort. We generated a dataset of 79 imputed variant call format files using the GLIMPSE1 tool, each containing an average of 9.5 million single nucleotide variants. Validation revealed a high imputation accuracy (squared Pearson correlation {approx}0.97) across sequencing platforms, showing GLIMPSE1\'s ability to confidently impute variants with minor allele frequencies as low as 2% in Spanish ancestry individuals. We conducted a comprehensive analysis of the patient cohort, examining hospitalisation and intensive care utilisation, sex and age-based differences, and clinical phenotypes using a standardised set of medical terms developed to characterise severe COVID-19 symptoms. The methods and findings presented here may be leveraged in future genomic projects, providing vital insights for health challenges like COVID-19.

Genomic Determinants of Long COVID (preprint)

Around 5–10% of adults may experience persistence of symptoms/signs beyond 4 to 12 weeks after acute SARS-CoV-2 infection. According to the World Health Organization, up to 40 million people suffer from Long COVID in Europe and the USA alone. The Centers for Disease Control and Prevention have encouraged the recognition of predictors for Long COVID. Any genetic markers associated to the disease have remained elusive to date. Here we explore the potential contribution of genetic traits to Long COVID. We used a well characterized cohort of 50 individuals with definitive diagnostic criteria for Long COVID from an initial set of patients of more than 1,200 with suspected Long COVID. All were attended at Hospital Puerta de Hierro, a large regional hospital in Madrid, Spain. All subjects had tested positive for SARS-CoV-2 RNA and/or antibodies, showed clinical manifestations for more than 6 months, and developed more than 5 persistent symptoms/signs. Low pass whole genome sequencing was performed in blood specimens for our selected cohort. From hundreds of polygenic risk scores (PRS) recorded at the PGS Catalog, we tested in our selected cohort a total of 12 PRS that passed our filtering criteria. Selected PRS encompassed distinct medical conditions, including cancers, hematologic, cardiovascular, endocrine, immunologic and neurological disorders. The calculated PRS in our patients produced a distribution of scores that was compared to a control ancestry-matched general population. We found significant differences for the PRS of traits ‘Tiredness/lethargy in the last 2 weeks’ and suggestive significance for ‘Depression’ when comparing Long COVID patients and controls. Our results strongly support a genetic susceptibility for Long COVID, with those scoring high in genetic predisposition for ‘tiredness’ as more likely to develop the disease. Results shed new light into the physiopathological basis for Long COVID, contrary to opinions considering it a subjective condition.

New susceptibility loci for severe COVID-19 by detailed GWAS analysis in European populations (preprint)

Due to the highly variable clinical phenotype of Coronavirus disease 2019 (COVID-19), deepening the host genetic contribution to severe COVID-19 may further improve our understanding about underlying disease mechanisms. Here, we describe an extended GWAS meta-analysis of 3,260 COVID-19 patients with respiratory failure and 12,483 population controls from Italy, Spain, Norway and Germany, as well as hypothesis-driven targeted analysis of the human leukocyte antigen (HLA) region and chromosome Y haplotypes. We include detailed stratified analyses based on age, sex and disease severity. In addition to already established risk loci, our data identify and replicate two genome-wide significant loci at 17q21.31 and 19q13.33 associated with severe COVID-19 with respiratory failure. These associations implicate a highly pleiotropic ~0.9-Mb 17q21.31 inversion polymorphism, which affects lung function and immune and blood cell counts, and the NAPSA gene, involved in lung surfactant protein production, in COVID-19 pathogenesis.

COMBINATION OF TOCILIZUMAB AND STEROIDS TO IMPROVE MORTALITY IN PATIENTS WITH SEVERE COVID-19 INFECTION: A SPANISH, MULTICENTER, COHORT STUDY (preprint)

BackgroundWe aimed to determine the impact of tocilizumab use in severe COVID-19 pneumonia mortality. MethodsWe performed a multicentre retrospective cohort study in 18 tertiary hospitals in Spain, from March to April 2020. Consecutive patients admitted with severe COVID-19 treated with tocilizumab were compared to patients not treated with tocilizumab, adjusting by Inverse Probability of the Treatment Weights (IPTW). Tocilizumab effect in patients receiving steroids during the 48h following inclusion was analyzed. ResultsDuring the study period, 506 patients with severe COVID-19 fulfilled inclusion criteria. Among them, 268 were treated with tocilizumab and 238 patients were not. Median time to tocilizumab treatment from onset of symptoms was 11 days (IQR 8-14). Global mortality was 23.7%. Mortality was lower in patients treated with tocilizumab than in controls (16.8% versus 31.5%, HR 0.514 [95CI 0.355-0.744], p< 0.001; weighted HR 0.741 [95CI 0.619-0.887], p = 0.001). Tocilizumab treatment reduced mortality by 14.7% relative to no tocilizumab treatment (RRR 46.7%). We calculated a number necessary to treat of 7. Among patients treated with steroids, mortality was lower in patients treated with tocilizumab than in those treated with steroids alone (10.9% versus 40.2%, HR 0.511 [95CI 0.352-0.741], p = 0.036; weighted HR 0.6 [95CI 0.449-0.804], p< 0.001) (Interaction p = 0.094). ConclusionsThese results show that survival of patients with severe COVID-19 is higher in patients treated with tocilizumab than in those not treated, and that tocilizumab effect adds to that of steroids administered to non-intubated cases with COVID-19 during the first 48 hours of presenting with respiratory failure despite of oxygen therapy. Randomised controlled studies are needed to confirm these results. SummaryWe investigated in-hospital mortality of patients with severe SARS-CoV-2 pneumonia in a multicenter series of patients treated with tocilizumab compared to controls, and adjusted using IPTW. Our results show a beneficial impact of tocilizumab treatment in SARS-CoV-2 pneumonia, that adds to that of steroids.