Single-stranded mRNA molecules, like those contained in the Pfizer and Moderna COVID-19 vaccines, are activators of innate immune cells. Binding of mRNA to innate immune cells produces a potent type I interferon (IFN) response that is thought to play a central role in inflammation in some patients with autoimmune disorders. [Specifically,] type I IFN is thought to play a role in the initiation phase of psoriasis when people first develop the disease, although chronic psoriasis is perpetuated by overactivation of a different pathway, the Th17 adaptive immune response.