The number of children with Mycoplasma pneumoniae–associated community-acquired pneumonia (CAP) infections rose sharply during 2024, according to data from U.S. pediatric hospital discharges.
M. pneumoniae is a leading cause of childhood CAP. During the COVID-19 pandemic, the prevalence of M. pneumoniae infections fell and remained low through 2023 (MMWR Morb Mortal Wkly Rep 2025;74[23]:394-400).
A Big Increase in 2024
An analysis of data from 42 children’s hospitals in the United States found discharges for M. pneumoniae CAP decreased in early 2020, remained low through 2023 and increased in all age groups in 2024.
From 2018 to 2024, ICD-10 codes for M. pneumoniae were listed for 11.5% of pediatric CAP hospitalizations. However, this number increased substantially in 2024, peaking at 53.8% during July 2024. This rate included cases among children 5 years of age and younger, a group that historically has been less affected by M. pneumoniae infection.
While cases increased, M. pneumoniae infections in 2024 were not more severe compared with previous years.
“This report includes important findings about Mycoplasma pneumoniae infections during the reemergence after the COVID-19 pandemic,” said Maureen H. Diaz, PhD, a microbiologist with the Division of Bacterial Diseases at the CDC’s National Center for Immunization and Respiratory Diseases.
Get the Word Out
Dr. Diaz noted that communicating the rise in M. pneumoniae to clinicians may be helpful. “Improved awareness among healthcare providers of periods of high M. pneumoniae transmission might improve diagnosis and could guide treatment of M. pneumoniae infections among children of all ages,” she said.
In addition, she noted that future surveillance and research could benefit from investigating characteristics in circulating M. pneumoniae strains globally and monitoring antibiotic resistance patterns. This should include tracking expanding macrolide resistance and emerging resistance to other antibiotic classes such as fluoroquinolones and tetracyclines that are sometimes used to treat M. pneumoniae infections.
“Additional research is needed to better understand trends in severe clinical syndromes associated with M. pneumoniae infection, such as reactive infectious mucocutaneous eruption,” she said.
Dr. Diaz reported no relevant financial disclosures.
