biostudies-literatureUnknownYao Ythe Fundamental Research Funds for the Central UniversitiesCAMS Innovation Fund for Medical SciencesNational Natural Science Foundation of ChinaChengdu University of Traditional Chinese MedicineNational medical and health science technology strategic platform and system construction projectNon-profit Central Research Institute Fund of Chinese Academy of Medical SciencesDespite considerable variation in disease manifestations observed among coronavirus disease 2019 (COVID-19) patients infected with severe acute respiratory syndrome coronavirus 2, the risk factors predicting disease severity remain elusive. Recent studies suggest that peripheral blood cells play a pivotal role in COVID-19 pathogenesis. Here, we applied two-sample Mendelian randomization (MR) analyses to evaluate the potential causal contributions of blood cell indices variation to COVID-19 severity, using single-nucleotide polymorphisms (SNPs) as instrumental variables for 17 indices from the UK Biobank and INTERVAL genome-wide association studies (N = 173 480). Data on the associations between the SNPs and very severe respiratory confirmed COVID-19 were obtained from the COVID-19 host genJournal of medical virologyhttps://www.ebi.ac.uk/biostudies/studies/S-EPMC9538306biostudies-literatureGenetic predisposition to blood cell indices in relation to severe COVID-19.PMC95383062021‐I2M‐1‐041No.2022‐I2M‐2‐003No.2022-I2M-2-0032021YFA11023002021-RC310-0152021-I2M-1-041Zhang FLiu JRao SYao YWang DJiang CSong HFeng QfalseGenetic predisposition to blood cell indices in relation to severe COVID-19.Despite considerable variation in disease manifestations observed among coronavirus disease 2019 (COVID-19) patients infected with severe acute respiratory syndrome coronavirus 2, the risk factors predicting disease severity remain elusive. Recent studies suggest that peripheral blood cells play a pivotal role in COVID-19 pathogenesis. Here, we applied two-sample Mendelian randomization (MR) analyses to evaluate the potential causal contributions of blood cell indices variation to COVID-19 severity, using single-nucleotide polymorphisms (SNPs) as instrumental variables for 17 indices from the UK Biobank and INTERVAL genome-wide association studies (N = 173 480). Data on the associations between the SNPs and very severe respiratory confirmed COVID-19 were obtained from the COVID-19 host gen2022-01-01T00:00:00Z2022 Aug2025-04-04T23:20:52.367Z2025-04-04T23:20:52.367ZS-EPMC95383063603901510.1002/jmv.28104