Elsevier established a free COVID-19 resource centre in January 2020, offering information in English and Mandarin. The centre grants permission for free access to its research in PubMed Central and other repositories. The article discusses the pathogenesis of SARS-CoV-2, focusing on viral sepsis as a key mechanism in severe cases. It highlights clinical observations of shock, metabolic acidosis, and multi-organ dysfunction in severe COVID-19 patients, suggesting viral sepsis rather than bacterial sepsis. Pathological studies show diffuse alveolar damage, viral particles in respiratory tissues, and involvement of other organs. The immune response involves proinflammatory cytokines, leading to cytokine storms and lymphopenia. The article hypothesizes that SARS-CoV-2 directly infects lymphocytes, contributing to immune suppression. Abnormal coagulation is also noted, with potential mechanisms involving ACE2 expression. The conclusion suggests that viral sepsis is crucial in severe cases, requiring antiviral therapy and immune modulation. The study proposes future research on SARS-CoV-2's effects on endothelial cells, coagulation, and immune responses. Contributors include researchers from various institutions, and the study declares no competing interests. The article is based on autopsy and basic science research, aiming to guide future investigations into SARS-CoV-2 pathogenesis.Elsevier established a free COVID-19 resource centre in January 2020, offering information in English and Mandarin. The centre grants permission for free access to its research in PubMed Central and other repositories. The article discusses the pathogenesis of SARS-CoV-2, focusing on viral sepsis as a key mechanism in severe cases. It highlights clinical observations of shock, metabolic acidosis, and multi-organ dysfunction in severe COVID-19 patients, suggesting viral sepsis rather than bacterial sepsis. Pathological studies show diffuse alveolar damage, viral particles in respiratory tissues, and involvement of other organs. The immune response involves proinflammatory cytokines, leading to cytokine storms and lymphopenia. The article hypothesizes that SARS-CoV-2 directly infects lymphocytes, contributing to immune suppression. Abnormal coagulation is also noted, with potential mechanisms involving ACE2 expression. The conclusion suggests that viral sepsis is crucial in severe cases, requiring antiviral therapy and immune modulation. The study proposes future research on SARS-CoV-2's effects on endothelial cells, coagulation, and immune responses. Contributors include researchers from various institutions, and the study declares no competing interests. The article is based on autopsy and basic science research, aiming to guide future investigations into SARS-CoV-2 pathogenesis.