Mycoplasma pneumoniae in a Missouri School District, Fall 2024

Respiratory illnesses are common among students and school staff. Most are caused by viruses, but some are caused by bacteria, including Mycoplasma pneumoniae. It mainly affects school-aged children and young adults, usually causing mild upper respiratory infections, but it can progress to the pneumonia commonly called "walking pneumonia." There is no vaccine against it.

After a period of low incidence during the COVID-19 pandemic, M. pneumoniae infections rose in 2023, and since spring 2024 CDC has reported increasing diagnoses in U.S. emergency departments, especially among children and adolescents. This CDC report describes what a school-based surveillance program in Missouri saw in fall 2024, including whether the bacteria were resistant to macrolide antibiotics, the recommended treatment for severe or persistent infections.

School KIDS

Knowledge of Infectious Diseases in Schools (School KIDS) monitors respiratory illness in a large public school district in Missouri. When a participating student (prekindergarten through grade 12) or staff member developed a new respiratory symptom — cough, fever, nasal congestion, shortness of breath, runny nose, wheezing or sore throat — they could submit a nasal swab, collected by themselves, a school nurse or a parent. Participants or parents completed a symptom survey, including days of school or work missed, and a follow-up survey 7 days later. Swabs were tested by PCR for M. pneumoniae and other bacteria and viruses, and positive samples were checked at CDC for mutations that make the bacteria resistant to macrolides.

What they found

From August 18 to November 6, 2024, 244 samples from 226 participants in 13 of the district's 33 schools included 21 that were positive for M. pneumoniae — from 18 students (seven in elementary, six in middle and five in high school) and three staff members.

• Three spikes. The share of positive tests peaked during September 29–October 5 (15.8%), October 13–19 (22.2%) and November 3–6 (19.2%), matching rising national trends among children aged 5 to 17.
• Who was infected. The students' median age was 11; 42.9% were female and 85.7% non-Hispanic White.
• Other germs too. Six of the 21 samples also carried another respiratory pathogen: rhinovirus or enterovirus in five, and parainfluenza virus type 4 in one.
• Symptoms. Cough was reported by 95.2% of those infected in the week before testing; nasal congestion, runny nose and sore throat were also common.
• Lasting illness. After 7 days, 11 participants (52.4%) still had symptoms. Sixteen (76.2%) missed at least one day of school or work, and nine (42.9%) sought medical care.
• Resistance was rare. Of the 15 samples whose macrolide susceptibility could be tested, one carried a resistance mutation.

What it means

The school data tracked national emergency department trends, suggesting M. pneumoniae may spread in schools, where its symptoms look much like those of respiratory viruses. The same measures that slow viruses, such as handwashing and covering coughs and sneezes, can help. Clinicians might consider testing for and treating M. pneumoniae in students or staff with persistent or severe respiratory symptoms. When antibiotics are prescribed, macrolides are a first-line treatment for moderate to severe laboratory-confirmed infections, and second-line antibiotics such as tetracyclines might be considered for persistent or severe symptoms.

The authors conclude that voluntary school-based surveillance can raise awareness of respiratory trends and guide prevention and careful antibiotic use during the fall and winter respiratory season.

Sources

• Olivia M. Almendares, Brittney Fritschmann, Rangaraj Selvarangan, Brian R. Lee, Chris Edens, Maureen Diaz, Brett Whitaker, Shannon Tilsworth, Janelle Porter, Nibha Sagar, Jennifer E. Schuster, Jennifer L. Goldman and Hannah L. Kirking, "Notes from the Field: School-Based Surveillance of Mycoplasma pneumoniae Trends and Impact on School Attendance by Students and Staff Members — Missouri, Fall 2024," Morbidity and Mortality Weekly Report, CDC: https://www.cdc.gov/mmwr/volumes/73/wr/mm7350a3.htm
• Some symptom percentages in the source do not match its count of 21 participants, and its count of viruses tested differs from its footnote; this page repeats neither. The report's figure is not reproduced.