Several of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines use a nucleoside-modified, purified mRNA lipid nanoparticle-encapsulated platform. Compared with traditional inactivated viral and adjuvanted protein vaccines, this RNA platform elicits far higher neutralizing antibody titers, stronger antigen-specific cluster of differentiation (CD) 4+ and CD8+ T-cell responses, and stronger germinal center B and TFH cell activation in experimental animals.1 The activated CD4+ and CD8+ T cells produce several proinflammatory cytokines, including interferon-γ and tumor necrosis factor-α.