Notes from the Field: Reemergence of Mycoplasma pneumoniae Infections in Children and Adolescents After the COVID-19 Pandemic, United States, 2018–2024

What is already known about this topic? Mycoplasma pneumoniae is a common cause of mild respiratory illness, though severe infection can lead to pneumonia. Resistance to macrolides, the recommended treatment, is widespread in Asia though uncommon in the United States. M. pneumoniae infections decreased globally during the COVID-19 pandemic. What is added by this report? Data from the National Syndromic Surveillance Program and the New Vaccine Surveillance Network showed an increase in M. pneumoniae in the United States beginning in fall 2023, though below prepandemic levels. What are the implications for public health practice? Providers might consider M. pneumoniae during fall and winter respiratory illness seasons. Macrolides remain the first-line treatment for M. pneumoniae infections in the United States. codes (ICD-10 J15.7 and J20.0§§). The percentage of M. pneumoniae–related diagnoses among pneumonia ED visits reported in NSSP decreased from 1.15% (4,681 of 407,514) during the prepandemic period to 0.35% (1,233 of 355,508) during the pandemic period and then increased to 0.89% (597 of 66,736) during the postpandemic period. Similarly, the percentage of test results within the NVSN §§ J.15.7: Pneumonia due to Mycoplasma pneumoniae; J20.0: acute bronchitis due to Mycoplasma pneumoniae. network that were positive for M. pneumoniae decreased from 1.2% (165 of 13,800) during the prepandemic period to 0.04% (10 of 24,256) during the pandemic period and then increased to 0.53% (13 of 2,470) during the postpandemic period (Figure). Fourteen M. pneumoniae–positive specimens collected at four NVSN sites during September 2023–January 2024 were sent to CDC for macrolide resistance testing. Among 14 specimens, 13 were determined to be susceptible to macrolides. Preliminary Conclusions and Actions Data collected by NSSP and NVSN demonstrate that the percentage of M. pneumoniae diagnoses and positive M. pneumoniae test results decreased during the COVID-19 pandemic. The percentage of diagnoses and positive test results have increased since September 2023 but remain below prepandemic levels. Among the small number of specimens available for testing, resistance to macrolides was uncommon. This report highlights the need for continued surveillance for M. pneumoniae infections and macrolide-resistant M. pneumoniae in the United States. Providers should consider M. pneumoniae as part of the differential diagnosis for cases of community-acquired pneumonia during fall and winter respiratory illness seasons. Despite ongoing concerns regarding antimicrobial resistance, macrolides remain the recommended first-line treatment for M. pneumoniae infections in the United States (5). FIGURE. Monthly number of Mycoplasma pneumoniae tests performed and percentage of positive test results among children and adolescents with acute respiratory illness — four sites, New Vaccine Surveillance Network, 2018–2023 1,000 1,200 Jan Apr Jul 2018 2019 2020 2021 2022 2023 Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct T o t a l Month and year Total tested % positive for M. pneumoniae 151 US Department of Health and Human Services | Centers for Disease Control and Prevention | MMWR | February 22, 2024 | Vol. 73 | No. 7 Corresponding author: Chris Edens, iek4@cdc.gov. 1Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, CDC; 2Coronavirus and Other Respiratory Viruses Division, National Center for Immunization and Respiratory Diseases, CDC; 3Detect & Monitor Division, Office of Public Health Data, Surveillance, and Technology, CDC; 4Maximus Federal Services, Inc., McLean, Virginia; 5ICF, Atlanta, Georgia; 6Children’s Mercy Hospital, Kansas City, Missouri; 7Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York; 8Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio; 9Texas Childre