Structure, genomic analysis, and pathogenesis of SARS-CoV-2

The severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease-2019 (COVID-19) pandemic, has caused havoc in the world. SARS-CoV-2 belongs to the genus of beta-coronaviruses, which are known to cause lower respiratory tract infections and pneumonia. The pathogenesis of COVID-19 involves the attachment, entry, and replication of the SARS-CoV-2 in the host cells. The overproduction of highly inflammatory cytokines results in a cytokine storm, leading to an increased risk of acute respiratory distress syndrome, vascular hyperpermeability, and multiorgan failure. The emergence of SARS-CoV-2 variants of concern (VOC) threatens the efforts to contain the COVID-19 pandemic. The emergence of VOC is responsible for the second or the third wave of COVID-19 cases in several countries. These variants harbor mutations in the spike protein that confer increased transmissibility or immune evasion. This chapter provides insight into the molecular structure of SARS-CoV-2, genomic analysis, emerging variants, and pathogenesis of COVID-19.