ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes lethal coronavirus disease (COVID-19). SARS-CoV-2 has been the chief source of threat to public health and safety from 2019 to the present. SARS-CoV-2 caused a sudden and significant rise in hospitalization due to respiratory issues and pneumonia. We are consistently uncovering new information about SARS-CoV-2, and yet so much is to explore to implement efficient interventions to combat the emergent variants and spread of the ongoing pandemic. Information regarding the existing COVID-19 pandemic is streamlining continuously. However, clinical symptoms of SARS-CoV-2 infections spanning from asymptomatic infection to severe death-instigating disease remain consistent with preliminary reports. In this review, we have briefly introduced highlights of the COVID-19 pandemic and features of SARS-CoV-2. We have focused on current knowledge of innate and adaptive immune responses during SARS-CoV-2 infections and persisting clinical features of recovered patients. Furthermore, we have discussed how these immune responses are not tightly regulated and imbalance can direct the latter phases of COVID-19, long-COVID symptoms, and cause detrimental immunopathogenesis. COVID-19 vaccines are also discussed in detail to describe the efforts going around the world to control and prevent the infection. Overall, we have summarized the current knowledge on the immunology of SARS-CoV-2 infection and the utilization of that knowledge in the development of a suitable COVID-19 therapeutics and vaccines.
