Diagnosis and Treatment Protocol for COVID-19 Patients (Tentative 9th Version).

Abstract

The 2019-nCoV (also as SARS-CoV-2) belongs to the beta genus of coronaviruses. It has an envelope, round or oval particles, and a diameter of 60 to 140nm. It has 5 essential genes, respectively targeting RNA-dependent RNA polymerase and 4 structural proteins of nucleoprotein (N), envelope protein (E), matrix protein (M), and spike protein (S). TheN protein wraps the RNA genome to form a nucleocapsid, which is surrounded by an E that contains the M and the S proteins. The S protein enters the cell by binding to angiotensin converting enzyme 2 (ACE-2). When isolated and cultured in vitro, the 2019-nCoV can be found in human respiratory epithelial cells in about 96hours, while it takes about 4 to 6days to isolate and culture in Vero E6 and Huh-7 cell lines. The 2019-nCoV, like all other viruses, mutates, and certain mutations may affect the biological characteristics of the virus. For example, the change in the binding affinity of the spike protein and ACE-2 may affect the virus’s ability of cell invasion, replication, and transmission, as well as period of recovery, antibodies produced after vaccination, and the neutralizing ability of antibody therapeutics. Therefore, such mutation has attracted wide attention. There are five “variants of concern” defined by the World Health Organization (WHO), namely Alpha, Beta, Gamma, Delta, and Omicron. At present, the Omicron variant has quickly replaced the Delta variant to become the dominant variant. Currently available evidence shows that the Omicron variant is more transmissible than the Delta variant, but with weakened pathogenicity. Omicron variant does not impact SARS-CoV-2 detection capability of RTPCR assays diagnostic, but it may reduce the neutralizing effect of some monoclonal antibody drugs.