inclusion criteria: * male and nonpregnant female patients 18 years of age or older * positive reverse-transcriptase-polymerase-chain-reaction (rt-pcr) assay for sars-cov-2 in a respiratory tract sample * pneumonia confirmed by chest imaging * additional risk factors for vte, as indicated by a total modified international medical prevention registry on venous thromboembolism (improve) risk score of 4 or higher * have received thromboprophylaxis with low-molecular-weight heparin, fondaparinux, or unfractionated heparin during the index hospitalization

inclusion criteria: * male and nonpregnant female patients 18 years of age or older * positive reverse-transcriptase-polymerase-chain-reaction (rt-pcr) assay for sars-cov-2 in a respiratory tract sample * pneumonia confirmed by chest imaging * additional risk factors for vte, as indicated by a total modified international medical prevention registry on venous thromboembolism (improve) risk score of 4 or higher * have received thromboprophylaxis with low-molecular-weight heparin, fondaparinux, or unfractionated heparin during the index hospitalization

inclusion criteria: - male and nonpregnant female patients 18 years of age or older - positive reverse-transcriptase-polymerase-chain-reaction (rt-pcr) assay for sars-cov-2 in a respiratory tract sample - pneumonia confirmed by chest imaging - additional risk factors for vte, as indicated by a total modified international medical prevention registry on venous thromboembolism (improve) risk score of 4 or higher - have received thromboprophylaxis with low-molecular-weight heparin, fondaparinux, or unfractionated heparin during the index hospitalization

inclusion criteria: - male and nonpregnant female patients 18 years of age or older - positive reverse-transcriptase-polymerase-chain-reaction (rt-pcr) assay for sars-cov-2 in a respiratory tract sample - pneumonia confirmed by chest imaging - additional risk factors for vte, as indicated by a total modified international medical prevention registry on venous thromboembolism (improve) risk score of 4 or higher - have received thromboprophylaxis with low-molecular-weight heparin, fondaparinux, or unfractionated heparin during the index hospitalization