to compare the antipyretic effects of ibuprofen in febrile children with serious bacterial infections (SBI), and children with a presumed viral infection.

A prospective cross- sectional study was conducted in a pediatric Emergency department between October 2018 and March 2020 for children aged 3 months to 4 years with a rectal temperature ≥ 38.5 °C.

Patients received 10 mg/kg of ibuprofen oral suspension. Rectal temperature was measured 60 and 120 min after administration. Laboratory and imaging evaluations were performed for each study participant in order to identify serious bacterial infection.

Ninety patients were included, of which 18 were diagnosed with serious bacterial infections. There was no significant difference in age, fever at presentation and duration of fever between the groups. No significant difference was noted in body temperature reduction at 60 and 120 min after ibuprofen administration (1.09 ± 0.75 °C vs 0.89 ± 0.58 °C, mean difference −0.12 °C, 95% CI −0.54–0.15 °C; 1.85 ± 0.53 °C vs 1.78 ± 0.83 °C, mean difference − 0.07 °C, 95% CI −0.49–0.36 °C, in the SBI and non-SBI groups respectively).

Fever response to Ibuprofen administration is not indicative of serious bacterial infections in children under 4 years of age. Larger prospective studies are required to define whether the lack of response to Ibuprofen has any impact on the management of febrile children.