Molecular biology of coronaviruses: an overview of virus-host interactions and pathogenesis

Coronaviruses (CoV) are enveloped, plus-strand RNA viruses that have the largest known RNA genomes and infect birds and mammals, causing various diseases. Human coronaviruses (HCoVs) were first identified in the mid-1960s and have been known to cause enteric or respiratory infections. In the last two decades, three HCoVs have emerged, including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which initiated the ongoing pandemic. SARS-CoV-2 causes a respiratory illness that presents as a mild upper respiratory disease but may result in acute respiratory distress syndrome, multi-organ failure and can be fatal, especially when underlying comorbidities are present. Children account for a low percentage of coronavirus disease 2019 (COVID-19) cases, with seemingly less severe disease. Most pediatric patients present mild or moderate symptoms or are asymptomatic. However, some cases may be severe. Therefore, SARS-CoV-2 infection and COVID-19 in pediatric patients must be studied in detail. This review describes general features of the molecular biology of CoVs and virus-host interactions that may be implicated in the pathogenesis of SARS-CoV-2.