IL6 and coinfection: For example, in our nomogram, a 15-month-old (59.1 points) RSV inpatient without preterm birth history (0 point) and seizures (0 point) had underlying condition (16.3 points), a NLR level of 4.0 (23.8 points), an IL-6 level of 20.0 pg/mL (57.4 points), a LDH level of 400.0 U/L (43.9 points), a D-dimer level of 2.5 mg/L (47.7 points), and co-infection (9.5 points).