The study investigated whether genetic variants in the genes for von Willebrand factor (VWF), factor VIII (FVIII), and ADAMTS13 were associated with the severity of COVID-19, the need for mechanical ventilation, and mortality.[2] Both common and low-frequency genetic variants were analyzed in a European cohort of patients with severe COVID-19 and in 3,495 Latin American patients.[2] In a Latin American population, they found a low-frequency variant in the VWF gene that was associated with the need for invasive mechanical ventilation.[2] No significant genetic associations with these genes were found in the European population.[2] Analysis of gene-gene interactions showed an interaction between the ADAMTS13 gene and the VWF genes.[2] The authors also investigated interactions between genetic factors and the environment, but did not specify the details in the summary.[2]