TLR9 and COVID-19: COVID-19 can trigger polymyalgia rheumatica, and this condition was also reported following vaccination; Autoimmune/inflammatory Syndrome Induced by Adjuvants (ASIA syndrome) has been proposed by some researchers, and the authors highlight that the peripheral mononuclear blood cells of these patients have elevated TLR-7 and TLR-9 expression, and that the mRNA vaccination can also trigger innate immunity via these receptors [126].