The study investigates the pathogenicity of SARS-CoV-2 in hACE2 transgenic mice, which express human ACE2, the receptor for SARS-CoV-2. The researchers infected hACE2 mice with the SARS-CoV-2 strain HB-01 and observed weight loss and viral replication in the lungs. Histopathological examination revealed interstitial pneumonia with infiltration of macrophages and lymphocytes, and accumulation of macrophages in alveolar cavities. Viral antigens were detected in bronchial epithelial cells, macrophages, and alveolar epithelia. These findings were not observed in wild-type mice infected with SARS-CoV-2. The study confirms the pathogenicity of SARS-CoV-2 in hACE2 mice, providing a valuable model for evaluating antiviral therapies and vaccines, as well as understanding the pathogenesis of COVID-19.The study investigates the pathogenicity of SARS-CoV-2 in hACE2 transgenic mice, which express human ACE2, the receptor for SARS-CoV-2. The researchers infected hACE2 mice with the SARS-CoV-2 strain HB-01 and observed weight loss and viral replication in the lungs. Histopathological examination revealed interstitial pneumonia with infiltration of macrophages and lymphocytes, and accumulation of macrophages in alveolar cavities. Viral antigens were detected in bronchial epithelial cells, macrophages, and alveolar epithelia. These findings were not observed in wild-type mice infected with SARS-CoV-2. The study confirms the pathogenicity of SARS-CoV-2 in hACE2 mice, providing a valuable model for evaluating antiviral therapies and vaccines, as well as understanding the pathogenesis of COVID-19.