Strategies Used by SARS-CoV-2 to Evade the Innate Immune System in an Evolutionary Perspective

By the end of 2019, the COVID-19 pandemic, resulting from the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), had diffused widely across the globe, with 770 million infected individuals and over 7 million deaths reported. In addition to its high infectivity and pathogenicity and its rapid mutation rate, the unique capacity of SARS-CoV-2 to circumvent the immune system has also contributed to the widespread nature of this pandemic. SARS-CoV-2 elicits the onset of innate immune system activation and initiates antiviral responses once it has infected the host. While battling the host's immune responses, SARS-CoV-2 has established many countermeasures to evade attack and clearance. As the exploration of SARS-CoV-2 continues, substantial evidence has revealed that the 29 proteins synthesized by the SARS-CoV-2 genome are integral to the viral infection process. They not only facilitate viral replication and transmission, but also assist SARS-CoV-2 in escaping the host's immune defenses, positioning them as promising therapeutic targets that have attracted considerable attention in recent studies. This review summarizes the manner in which SARS-CoV-2 interfaces with the innate immune system, with a particular focus on the continuous evolution of SARS-CoV-2 and the implications of mutations.