After 4 months of infection, patients with PCC and patients without PCC-related symptoms did not differ in regard to the concentration of circulating cytokines, but both groups presented higher levels of circulating IFN-α, IFN-λ1, IP-10 and IL-8, in relation to the other groups (healthy controls and volunteers exposed to other coronaviruses) (35). This evidence concerns the gene IFNA2 and infection.