The addition of IL6 levels alone in IL6-m-EASIX showed the largest increase in AUC for ROC analysis compared to the other scores in the discriminatory function for predicting CRS progression to grade ≥ 2 on day +3 (OR 1.57; p = 0.031, AUC 89.7%; p = 0.0040) and compared to m-EASIX (OR 1.59; p = 0.0015, AUC 79.9%; p = 0.0011). The gene discussed is IL6; the disease is congenital rubella syndrome.