Changes of Mycoplasma Pneumoniae Pneumonia Among Chinese Children, 2019-2023

Abstract Objective To describe the epidemiology and clinical characteristics of Mycoplasma Pneumoniae-associated hospitalizations among children in Shanghai, a south province of China before, during and post-COVID-19 Pandemic (2019-2023). Methods From January 2019 to December 2023, an observational cross-sectional study was conducted, and the trend, season distribution and age group of hospitalization children with mycoplasma pneumoniae pneumonia was investigated. The clinical data of Mycoplasma pneumoniae pneumonia in 2019 and 2023 were compared to describe the changes in the two periods of Mycoplasma pneumoniae prevalence. Results 1123 children hospitalized by mycoplasma pneumoniae pneumonia were rolled. The number of hospitalized children with Mycoplasma pneumoniae pneumonia peaked in 2019（411cases） and 2023（548 cases）, during the COVID-19 pandemic (2020-2022), and the cases decreased significantly, especially in 2020 (37 cases). Children aged 3-7 years account for the majority of hospitalized children with Mycoplasma pneumoniae pneumonia，208 cases (50.6%) in 2019,22 cases (59.5%) in 2020,56 cases (65.1%),18 cases (43.9%) in 2022. However, 267 children (48.7%) aged > 7 years old age in 2023. The mean time of duration of fever before admission and total duration of fever in 2023 were longer than those in 2019(4.91±2.48 days vs 3.91±2.60 days , P=0.000; 5.56±3.34 days vs 4.51±3.31 days, P=0.000，respectively).Cases of severe pneumonia and labor pneumonia in 2023, post the COVID-19 pandemic, were higher than those in 2019( 195(35.6%) vs60(14.6%),P=0.000; 288(52.6%)vs 113(27.5%),P=0.000，separately). Conclusion During COVID-19 epidemic, the number of hospitalizations for Mycoplasma pneumoniae pneumonia decreased exceedingly. The seasonal prevalence of mycoplasma pneumoniae was not changed by the COVID-19 pandemic. The time of fever and the proportion of lobar and severe pneumonia in Mycoplasma pneumoniae pneumonia were increased post the COVID-19 pandemic.