IL18 and COVID-19: Compared to patients with influenza, patients with COVID-19 had increased levels of interferon (IFN)-γ (mean difference (MD) 4.14; 95% CI 1.36–12.58; p = 0.008), interleukin (IL)-4 (MD 1.82; 95% CI 1.12–2.97; p = 0.012), IL-5 (MD 2.22; 95% CI 1.09–4.52; p = 0.024), and IL-6 (MD 2.41; 95% CI 1.02–5.68; p = 0.044) and increased IFN-γ (MD 6.10; 95% CI 2.53–14.71; p < 0.001) and IL-10 (MD 2.68; 95% CI 1.53–4.69; p < 0.001) compared to patients with bacterial CAP, but no difference in IL-1β, tumor necrosis factor-α, IL-8, IL-18, IL-12p70, C-reactive protein, and adiponectin.