Introduction to the Virus and Its Infection Stages

Coronavirus disease 2019 (COVID-19) originated from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which has been affecting numerous people in many countries. Many patients have been involved with various disorders and complications like acute lung injury (ALI) and cytokine storm leading to mortality in severe cases. Consequently, this disaster has propelled scientists and pharmaceutical companies to develop practical vaccines and employ the drug repurposing approach to inhibit the disease. Taking the biology and pathogenesis stages of the SARS-CoV-2 infection into account, it is demonstrated that COVID-19 is associated with direct damages induced by the virus, besides the host inflammatory and immune responses. Accordingly, this chapter is planned to sequentially discuss the biology of SARS-CoV-2 and the stages of the virus pathogenesis.