ABSTRACT
All viruses have to overcome the innate immune response in order to establish infection. Methods have been developed to assay if, and how, viruses overcome these responses, and many can be directly applied to coronaviruses. Here, in vitro methods to determine how coronaviruses overcome this response are described.
Subject(s)
Coronavirus/growth & development , Coronavirus/metabolism , Virus Cultivation/methods , Animals , Cell Line , Coronavirus/pathogenicity , Host-Pathogen Interactions , Humans , Immunity, Innate/immunology , Interferons , Middle East Respiratory Syndrome Coronavirus/growth & development , Middle East Respiratory Syndrome Coronavirus/pathogenicity , RNA, Viral , Viral Nonstructural Proteins , Virus ReplicationABSTRACT
The MERS-CoV isolated during the 2015 nosocomial outbreak in Korea showed distinctive differences in mortality and transmission patterns compared to the prototype MERS-CoV EMC strain belonging to clade A. We established a BAC-based reverse genetics system for a Korean isolate of MERS-CoV KNIH002 in the clade B phylogenetically far from the EMC strain, and generated a recombinant MERS-CoV expressing red fluorescent protein. The virus rescued from the infectious clone and KNIH002 strain displayed growth attenuation compared to the EMC strain. Consecutive passages of the rescued virus rapidly generated various ORF5 variants, highlighting its genetic instability and calling for caution in the use of repeatedly passaged virus in pathogenesis studies and for evaluation of control measures against MERS-CoV. The infectious clone for the KNIH002 in contemporary epidemic clade B would be useful for better understanding of a functional link between molecular evolution and pathophysiology of MERS-CoV by comparative studies with EMC strain.
Subject(s)
DNA, Complementary/toxicity , Middle East Respiratory Syndrome Coronavirus/genetics , Animals , Cell Line, Tumor , Chlorocebus aethiops , Clone Cells , Cricetinae , Humans , Middle East Respiratory Syndrome Coronavirus/growth & development , Receptors, Virus/metabolism , Vero Cells , Viral Proteins/metabolismABSTRACT
Patients and physicians worldwide are facing tremendous health care hazards that are caused by the ongoing severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) pandemic. Remdesivir (GS-5734) is the first approved treatment for severe coronavirus disease 2019 (COVID-19). It is a novel nucleoside analog with a broad antiviral activity spectrum among RNA viruses, including ebolavirus (EBOV) and the respiratory pathogens Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV, and SARS-CoV-2. First described in 2016, the drug was derived from an antiviral library of small molecules intended to target emerging pathogenic RNA viruses. In vivo, remdesivir showed therapeutic and prophylactic effects in animal models of EBOV, MERS-CoV, SARS-CoV, and SARS-CoV-2 infection. However, the substance failed in a clinical trial on ebolavirus disease (EVD), where it was inferior to investigational monoclonal antibodies in an interim analysis. As there was no placebo control in this study, no conclusions on its efficacy in EVD can be made. In contrast, data from a placebo-controlled trial show beneficial effects for patients with COVID-19. Remdesivir reduces the time to recovery of hospitalized patients who require supplemental oxygen and may have a positive impact on mortality outcomes while having a favorable safety profile. Although this is an important milestone in the fight against COVID-19, approval of this drug will not be sufficient to solve the public health issues caused by the ongoing pandemic. Further scientific efforts are needed to evaluate the full potential of nucleoside analogs as treatment or prophylaxis of viral respiratory infections and to develop effective antivirals that are orally bioavailable.
Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Antiviral Agents/pharmacology , Coronavirus Infections/drug therapy , Hemorrhagic Fever, Ebola/drug therapy , Pneumonia, Viral/drug therapy , Severe Acute Respiratory Syndrome/drug therapy , Adenosine Monophosphate/pharmacokinetics , Adenosine Monophosphate/pharmacology , Alanine/pharmacokinetics , Alanine/pharmacology , Antiviral Agents/pharmacokinetics , Betacoronavirus/drug effects , Betacoronavirus/growth & development , Betacoronavirus/pathogenicity , COVID-19 , Clinical Trials as Topic , Compassionate Use Trials/methods , Coronavirus Infections/mortality , Coronavirus Infections/pathology , Coronavirus Infections/virology , Drug Administration Schedule , Ebolavirus/drug effects , Ebolavirus/growth & development , Ebolavirus/pathogenicity , Hemorrhagic Fever, Ebola/mortality , Hemorrhagic Fever, Ebola/pathology , Hemorrhagic Fever, Ebola/virology , Humans , Middle East Respiratory Syndrome Coronavirus/drug effects , Middle East Respiratory Syndrome Coronavirus/growth & development , Middle East Respiratory Syndrome Coronavirus/pathogenicity , Pandemics , Patient Safety , Pneumonia, Viral/mortality , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Severe acute respiratory syndrome-related coronavirus/drug effects , Severe acute respiratory syndrome-related coronavirus/growth & development , Severe acute respiratory syndrome-related coronavirus/pathogenicity , SARS-CoV-2 , Severe Acute Respiratory Syndrome/mortality , Severe Acute Respiratory Syndrome/pathology , Severe Acute Respiratory Syndrome/virology , Survival Analysis , Treatment OutcomeABSTRACT
The purpose of this paper is to reveal the spread rules of the three pneumonia: COVID-19, SARS and MERS. We compare the new spread characteristics of COVID-19 with those of SARS and MERS. By considering the growth rate and inhibition constant of infectious diseases, their propagation growth model is established. The parameters of the three coronavirus transmission growth models are obtained by nonlinear fitting. Parametric analysis shows that the growth rate of COVID-19 is about twice that of the SARS and MERS, and the COVID-19 doubling cycle is two to three days, suggesting that the number of COVID-19 patients would double in two to three days without human intervention. The infection inhibition constant in Hubei is two orders of magnitude lower than in other regions, which reasonably explains the situation of the COVID-19 outbreak in Hubei.