COVID-19 infection: Origin, transmission, and characteristics of human coronaviruses

Shereen, Muhammad Adnan; Khan, Suliman; Kazmi, Abeer; Bashir, Nadia; Siddique, Rabeea

Initially, interferons-a nebulization, broad-spectrum antibiotics, and anti-viral drugs were used to reduce the viral load [49, 51, 52] , however, only remdesivir has shown promising impact against the virus [53] . Remdesivir only and in combination with chloroquine or interferon beta significantly blocked the SARS-CoV-2 replication and patients were declared as clinically recovered [46, 50, 52] . Various other anti-virals are currently being evaluated against infection. Nafamostat, Nitazoxanide, Ribavirin, Penciclovir, Favipiravir, Ritonavir, AAK1, Baricitinib, and Arbidol exhibited moderate results when tested against infection in patients and in-vitro clinical isolates [46, 48, 50, 52] . Several other combinations, such as combining the antiviral or antibiotics with traditional Chinese medicines were also evaluated against SARS-CoV-2 induced infection in humans and mice [46] . Recently in Shanghai, doctors isolated the blood plasma from clinically recovered patients of COVID-19 and injected it in the infected patients who showed positive results with rapid recovery [54] . In a recent study, it was identified that monoclonal antibody (CR3022) bindswith the spike RBD of SARS-CoV-2. This is likely due to the antibody's epitope not overlapping with the divergent ACE2 receptor-binding motif. CR3022 has the potential to be developed as a therapeutic candidate, alone or in combination with other neutralizing antibodies for the prevention and treatment of -COVID-19 infection [55] . Subgroup clusters are labeled as 1a and 1b for the Alphacoronavirus and 2a, 2b, 2c, and 2d for the Betacoronavirus. This tree is based on the published trees of Coronavirinae [3, 41] and reconstructed with sequences of the complete RNA-dependent RNA polymerase-coding region of the representative novel coronaviruses (maximum likelihood method using MEGA 7.2 software). severe acute respiratory syndrome coronavirus (SARS-CoV); SARS-related coronavirus (SARSr-CoV); the Middle East respiratory syndrome coronavirus (MERS-CoV); porcine enteric diarrhea virus (PEDV); Wuhan seafood market pneumonia (Wuhan-Hu-1). Bat CoV RaTG13 Showed high sequence identity to SARS-CoV-2 [42] . (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)