IL10 and viral infectious disease: The elevated IL-10 level represents a notable feature following numerous viral infections, such as SARS-CoV-2 [25], influenza A virus [26], LCMV [6], HIV [27], porcine reproductive and respiratory syndrome virus (PRRSV) [28], porcine circovirus type 2 (PCV2) [29,30], FMDV [31], and others (Table 1).