A novel coronavirus—from basic research to clinic

The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is now sweeping the globe like the toppling Dominoes, and has become an alarming public health issue worldwide. To date, there have been more than 76 million confirmed cases and more than 1,690,000 deaths worldwide. SARS-CoV-2 might originate from bats and is usually transmitted through respiratory droplets and contact. The SARS-CoV-2 genome is about 30 kilobases in length, encoding 16 non-structural proteins and 4 structural proteins. The receptor-binding domain (RBD) in the S1 subunit of the spike (S) protein of SARS-CoV-2 interacts with the entry receptor angiotensin-converting enzyme 2 (ACE2) on host alveolar type II epithelial cells. The interaction causes structural changes in the S2 subunit leading to virus-host cell fusion. RNA-dependent RNA polymerase (RdRp) is vital to replication of the viral genome. ACE2 may be downregulated after infection, leading to lung edema and injury. Common symptoms of SARS-CoV-2 infection include fever, dry cough, dyspnea, fatigue, and myalgia, that is, a pneumonia that has been termed coronavirus disease-2019 (COVID-19) by the World Health Organization. COVID-19 can be fatal. The imaging findings of the lung are mostly multiple ground glass shadows and subsegmental consolidation near the pleura. SARS-CoV-2 can be detected by nucleic acid and antibody tests, virus isolation, and electron microscopy. The pathological features of COVID-19 are diffuse alveolar injury, fibrous myxoid exudate, interstitial inflammation, alveolar epithelial cell proliferation and shedding, and hyaline membrane formation. At present, antivirals are non-specific and mainly include lopinavir/ritonavir, remdesivir, and umifenovir. EK1 peptide and SARS-CoV-2-HR2P may be novel antiviral agents that can prevent infection. Convalescent plasma is generally a valid option. Although no vaccine is officially available, there are inactivated vaccines, vectored vaccines and nucleic acid-based vaccines in clinical trials. Prompt and strong measures have been taken to prevent the transmission of SARS-CoV-2 in China.