AICDA and COVID-19: The presence of multilevel complexity underlying COVID-19 as multifactorial disease, with multiple interrelated pathomechanisms acting in parallel, multiplied by the complexity of the AID/APOBEC family, which is characterized by cell/tissue type-specific expression patterns, polymorphisms, DNA/RNA targeting specificity, and a plethora of antiviral functions, calls for the necessity of implementation of a holistic approach.