CALCA and influenza: Compared to patients with COVID-19, patients with influenza (A and B) showed a higher frequency of elevated CRP (hazard ratio, HR = 3.567, 95%CI: 1.565–8.133, p < 0.05, Figure 4); PCT (HR = 5.261, 95%CI: 2.068–13.385, p < 0.001); and LDH (HR = 7.436, 95%CI: 2.525–21.897, p < 0.001), but a lower frequency of elevated HBDH (HR = 0.301, 95%CI: 0.130–0.695, p = 0.005).