The CDC reports a significant increase in cases of walking pneumonia among children this year.

Dr. Buddy Creech, a pediatric infectious disease specialist at Vanderbilt University Medical Center, noted that the issue has been on their radar since early summer, when a significant increase in pneumonia cases among children was observed.

In August, four pediatricians from the Nashville area contacted Dr. Creech, puzzled by the rise in coughing among kids during the summer months. They sought guidance because their usual antibiotic, amoxicillin, wasn't effective for these patients.

This pneumonia is caused by the Mycoplasma pneumoniae bacteria, which has seen a notable increase in cases, especially among preschoolers, as reported by the CDC. The agency recently alerted parents and healthcare providers about this trend.

Mycoplasma pneumonia is one of several respiratory infections currently challenging doctors, alongside rising cases of whooping cough (pertussis) and respiratory syncytial virus (RSV), which is also on the rise in parts of the country.

Historically, testing for Mycoplasma has been complicated, as the bacteria do not grow well in standard culture methods. However, improved diagnostic tests now allow for quicker and more reliable detection, which is crucial given the array of respiratory illnesses affecting children this fall.

The CDC emphasizes the importance of recognizing the Mycoplasma trend since first-line antibiotics like amoxicillin and penicillin are ineffective against this bacteria. Typically, it can be effectively treated with other antibiotics, such as azithromycin.

According to the CDC's data, the percentage of children aged 2 to 4 who visited the emergency room for pneumonia and tested positive for Mycoplasma increased from 1% in April 2024 to 7.2% by early October—a sevenfold increase. The diagnosis rate for older children also doubled during the same period, from 3.6% to 7.4%.

While cases of Mycoplasma appear to have peaked in mid-August, they remain elevated. Dr. Creech anticipates that this trend will persist for another month before tapering off as fall progresses.

On X-rays, Mycoplasma infections can cause a "cloudy" appearance in the lungs, often referred to as "white lung."

Other countries, including China, Denmark, and France, reported increases in similar pneumonia cases last year.

Several factors may explain this rise, according to Dr. Geoffrey Weinberg, a pediatric infectious disease specialist at the University of Rochester Medical Center.

First, Mycoplasma infection rates are returning to pre-COVID levels. Although the current increase seems significant, it is partly due to the sharp decline in other infections during the pandemic.

Second, infections often cycle, with spikes occurring every three to seven years as immunity wanes. Dr. Weinberg noted that having a significant number of cases after a period of low incidence can amplify the perceived increase.

Third, advancements in diagnostic technology, such as multiplex tests, allow for simultaneous testing for various viruses and bacteria, likely leading to more frequent detection of Mycoplasma infections.

Mycoplasma pneumoniae spreads through respiratory droplets, making it common in crowded environments like schools, dormitories, and nursing homes. The bacteria can remain in the body for one to four weeks before symptoms appear, complicating exposure tracing.

Infection symptoms often start mildly, with headaches, sore throats, low fevers, and chills, leading to the term “walking pneumonia.” The cough typically begins dry and gradually becomes more persistent over two to three weeks.

Not all individuals with Mycoplasma infections require treatment; about 75% of children and young adults recover without intervention. However, the infection can worsen pre-existing conditions like asthma and lead to severe illness in some cases.

Rarely, the bacteria can spread beyond the lungs, infecting the central nervous system and potentially affecting the brain, spinal cord, and nerves, which may not result in a cough.