TNF and acute respiratory distress syndrome: The host immune responses, including severe pro-inflammation with elevated cytokines in sera and BALF, particularly IL-6, IL-1β, and TNF-α, and impaired interferon responses, are markers of severe disease, manifesting as ARDS in some patients with COVID-19.2,26–28 Here, we investigated how the cytokine levels changed in mice followed by the inactivated SARS-CoV-2 instillation.