COVID-19 patients display high levels of inflammatory cytokines and chemokines [77], especially severe-stage patients, who are known to exhibit elevated expression of TNFα, IL-1, IL-6, IL-18, IL-8, IL-10, MCP-1, and MIP-1α, supporting that idea systemic inflammation and infection is evident in the peripheral blood of COVID-19 patients. Here, IL18 is linked to infection.