Human Coronavirus OC43 as a Low-Risk Model to Study COVID-19

Abstract

The coronavirus disease 2019 (COVID-19) pandemic has had irreversible and devastating impacts on every aspect of human life. To better prepare for the next similar pandemic, a clear understanding of coronavirus biology is a prerequisite. Nevertheless, the high-risk nature of the causative agent of COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), requires the use of a cumbersome biosafety level-3 (BSL-3) confinement facility. To facilitate the development of preventive and therapeutic measures against SARS-CoV-2, one of the endemic strains of low-risk coronaviruses has gained attention as a useful research alternative: human coronavirus OC43 (HCoV-OC43). In this review, its history, classification, and clinical manifestations are first summarized. The characteristics of its viral genomes, genes, and evolution process are then further explained. In addition, the host factors necessary to support the life cycle of HCoV-OC43 and the innate, as well as adaptive, immunological responses to HCoV-OC43 infection are discussed. Finally, the development of in vitro and in vivo systems to study HCoV-OC43 and its application to the discovery of potential antivirals for COVID-19 by using HCoV-OC43 models are also presented. This review should serve as a concise guide for those who wish to use HCoV-OC43 to study coronaviruses in a low-risk research setting.

Feasibility Study of Developing a Saline-Based Antiviral Nanoformulation Containing Lipid-Soluble EGCG: A Potential Nasal Drug to Treat Long COVID

“…In summary, it is known that the root cause of Long COVID-associated OD is persistent viral presence (persistent infection), inflammation of olfactory epithelia, and apoptosis of the epithelial/neuronal cells [ 4 ]. The results of the current study demonstrated that EC16/EC16m in the saline-based nanoformulations was able to rapidly inactivate β-coronavirus OC43, the strain with high genome homology with SARS-CoV-2 [ 28 ] by direct contact (1 min), and to reduce cytopathic effect after a post-infection treatment (10 min). With the known anti-inflammatory, antioxidant, and neuroprotective properties, intranasally delivered EC16m could potentially not only terminate the “persistent infection” in the OE, but also inhibit local inflammation and apoptosis, thereby normalizing the olfactory function and inhibit inflammation in the CNS.…”

Evaluation of Novel Nasal Mucoadhesive Nanoformulations Containing Lipid-Soluble EGCG for Long COVID Treatment

“…In summary, the results of the current study demonstrated that the saline-based EC16m mucoadhesive nasal Formulation D is highly effective against human β-coronavirus OC43, the strain with high genome homology with SARS-CoV-2 (45), and in reducing viral replication after a single 5-min post-infection treatment, without mucociliary toxicity. With the known anti-inflammatory, antioxidant, and neuroprotective properties, intranasally delivered EC16m by Formulation D could not only terminate the "persistent infection" in the olfactory epithelium, but also inhibit local inflammation and apoptosis, thereby restore the olfactory function and reduce free radical levels and inflammation in the CNS.…”

Bioinformatic identification of Endemic Coronaviruses’ epitopes in SARS-CoV-2 genomes isolated in Kenya

“…Cross-reactive T-cell epitopes have also been identi ed between SARS-CoV-2, HCoVs, and live attenuated vaccines (LAVs), further emphasizing the potential for pre-existing immunity to in uence COVID-19 outcomes 14 . This is due to their closeness in their molecular structures 15 . Analysis of known epitope sequences from SARS-CoV, SARS-CoV-2, and other Coronaviridae has revealed conserved epitopes between SARS-CoV-2 and SARS-CoV, particularly in the nucleoprotein and spike glycoprotein, suggesting shared antigenic sites that could be targeted for vaccine development 16,17 .…”