IFNG and COVID-19: As previously mentioned, immunoglobulins, cytokines, and chemokines play an important role in shaping immunity in response to infection and vaccination, and some authors have declared that patients with severe COVID-19 have substantially increased IL-1β, IL-2, IL-6, IL-7, IL-8, IL-10, IL-17, IFN-γ, G-CSF, and TNF-α, showing a predictive effect [19,20].