In another in vivo study with mice, IAV and SARS-CoV-2 were coinfected sequentially; the single infection of IAV caused increased levels of tumor necrosis factor-alpha (TNF-α), interleukin-1 alpha (IL-1α), IL-6, and interferon beta (IFN-β), while single infection with SARS-CoV-2 caused moderate increases in IL-1α, IL-6, and IFN-β, lower than those observed in IAV single infection. Here, TNF is linked to infection.