Children with pneumonia had significantly lower SatO2 (p 0.001) and higher CRP levels (p 0.023) and they required oxygen supplementation to maintain SatO2 ≥ 92% in a higher percentage (p < 0.0001) and for longer time (p < 0.0001) compared to the patients with simple bronchiolitis. This evidence concerns the gene CRP and susceptibility to pneumonia measurement.