Childhood Mycoplasma pneumoniae : epidemiology and manifestation in Northeast and Inner Mongolia, China

Mycoplasma pneumoniae (MP) is commonly detected in children. However, the epidemiological trends of MP in Northeast (NE) China are unclear. This retrospective study aimed to investigate the prevalence of MP infections in this understudied region. The clinical manifestations and bronchoscopic findings observed in hospitalized patients with severe Mycoplasma pneumoniae pneumonia (SMPP) were collected from comprehensive data obtained from six tertiary hospitals in NE and Inner Mongolian (IM) China, from 1 January 2017 to 31 December 2023. A total of 5,593,530 children who visited the outpatient and emergency departments, and 412,480 inpatient hospitalized children were included in the study. The positivity rate of MP immunoglobulin M (IgM) in the children who visited the outpatient and emergency departments varied from 7.80% to 10.12%, whereas that of MP infection in hospitalized children ranged from 27.18% to 30.10%. Children hospitalized for MP infection were mainly concentrated in the 1- to 4-year (41.39%) and 4- to 7-year (24.25%) age groups. Before 2020, the season with the highest incidence of MP was winter. After the implementation of non-pharmaceutical interventions (NPIs), the MP epidemic season changed, and the number of children with MP infections decreased; however, the proportion of MP infections in hospitalized children did not change significantly. Starting from August 2023, the MP infection rate in outpatient, emergency, and hospitalized children increased sharply, with SMPP and its complications (e.g., plastic bronchitis and pleural effusion) increasing significantly. MP is prevalent in NE and IM, China. When the NPIs ended, MP infection showed a delayed outbreak trend, and the number of children with severe infection increased significantly.

IMPORTANCE

In Northeastern (NE) and Inner Mongolia (IM), the incidence of Mycoplasma pneumoniae (MP) infections, including severe Mycoplasma pneumoniae pneumonia (SMPP), is high, posing health risks and imposing substantial economic burdens on the local population. Therefore, it is imperative to prioritize the study of MP prevalence and address the research gaps in MP epidemiology in these areas of China. We obtained a comprehensive collection of pediatric outpatient, emergency, and inpatient data from six public Grade III hospitals. We believe that our study makes a significant contribution to the literature because understanding regional variations in MP infections can help healthcare professionals tailor prevention and treatment strategies, and studying bronchoscopic manifestations can provide insights into the impact of the disease on the respiratory system, potentially leading to a more effective clinical management.