CRP and Increased total leukocyte count: In male infants, infants aged < 1 month, infants that appeared to be well, Jews, and infants with leukocytosis > 15 × 109/L or a CRP > 2 mg/dL, the presence of respiratory symptoms reduced the risk of SBIs (p = 0.005, p = 0.011, p = 0.014, p = 0.003, and p < 0.001, respectively).