Objective: To investigate the clinical characteristics and prognosis of Mycoplasma pneumoniae pneumonia (MPP) in infants and young children

so as to provide reference for the clinical diagnosis and treatment. Methods: Retrospective analysis was performed on the clinical data of 435 infants and young children with MPP admitted into Yuying Children’s Hospital of Wenzhou Medical University from Jan. 2015 to Jun. 2018. According to different age groups

all children were divided into 139 cases in the infants and young children group

163 cases in the preschool age group

and 133 cases in the school age group. Clinical manifestations

laboratory indicators

imaging characteristics

treatment and prognosis of two groups were compared. Results: The clinical symptoms of MPP in the infants and young children group were significant. Compared with other age groups

the infants and young children group had lower proportion of increased C-reactive protein

higher proportion of increased white blood cell count

and higher lactate dehydrogenase and platelet levels. The chest X-ray of the infants and young children group was mainly in form of small flake or patchy shadow and easy to be infected by mixed respiratory tract virus. The infants and young children group had better prognosis after positive and reasonable treatment. And 97.50% (39/40) of the infants and young children with large lober parenchyma infiltration returned to normal chest X-ray within one month and had no clinical manifestations

no sequelae and recurrent MP infection. Conclusion: The clinical symptoms of infants and young children with MPP are significant and the imaging manifestations are mainly in form of small flake or patchy shadow

and easily to be infected by respiratory tract virus. With positive and rational treatment

most infants and young children with MPP can be cured.