CASC2 and pneumonia: CASC2 (hazard ratio [HR] = 0.068, 95% confidence interval [CI] = 0.016–0.292, P < 0.001) and age (HR = 2.806, 95% CI = 1.240–6.394, P < 0.001) were independent influence factor for the poor prognosis of children with severe pneumonia.