Prolonged coughs in children may signal a resurgence of a specific form of pneumonia that has been on the rise across the United States this year, necessitating a distinct antibiotic treatment, according to infectious disease specialists. "We've been closely monitoring this issue since the early summer when we observed a significant surge in pneumonia cases among children exhibiting this particular strain," noted Dr. Buddy Creech, a pediatric infectious disease expert at Vanderbilt University Medical Center. Creech recounted that in August, on a single day, four pediatricians from the Nashville area contacted him, inquiring about the unusual prevalence of children with coughs during the summer. These physicians sought his guidance, as their standard antibiotic for pneumonia, amoxicillin, appeared ineffective against this new strain. This form of pneumonia is caused by the Mycoplasma pneumoniae bacteria, and there has been a notable increase in cases this year, particularly among preschool-aged children, as reported by the US Centers for Disease Control and Prevention (CDC), which issued an alert to parents and healthcare providers last week. Mycoplasma pneumonia has joined a growing list of respiratory infections challenging medical professionals this season. Cases of whooping cough, or pertussis, which also result in persistent coughing, have increased fivefold compared to this time last year, and the respiratory syncytial virus (RSV) is also on the rise in certain regions of the US.

In the past, diagnosing Mycoplasma was challenging due to its resistance to growth in a Petri dish, the conventional method for testing bacterial infections. Creech explained that improved diagnostic tests have facilitated the swift and reliable detection of these bacteria. With the multitude of pathogens causing coughs in children this fall, it is imperative for doctors to utilize these new tests for accurate diagnosis, he emphasized. "We are at a critical juncture where we must employ these diagnostic tests to inform treatment," he stated. The CDC underscores the importance of recognizing the Mycoplasma trend, as first-line antibiotics like amoxicillin and penicillin are ineffective against this bacteria. Fortunately, the infection can typically be treated with alternative antibiotics, such as azithromycin. According to the CDC, which tracks discharge data from a network of hospitals and test results from commercial labs, the number of children aged 2 to 4 who visited the ER for pneumonia and tested positive for Mycoplasma increased from 1% in April 2024 to 7.2% in early October, marking a sevenfold increase. Diagnoses among older children also doubled during the same period, rising from 3.6% to 7.4%. The CDC reported that while Mycoplasma cases may have peaked in mid-August, they remain elevated. Creech anticipates that the cases will continue to be high for another month or so before gradually decreasing later in the fall.

On X-rays, Mycoplasma infections can cause the lungs to appear cloudy, or exhibit a "white lung" appearance. Last year, China, Denmark, and France all reported increases in this type of pneumonia among children. Dr. Geoffrey Weinberg, a pediatric infectious disease specialist at the University of Rochester Medical Center, identified three likely factors contributing to the rise in cases. Firstly, Mycoplasma infection rates are returning to pre-pandemic levels. "The increase seems dramatic now, but it's more noticeable because during the peak of the Covid pandemic, the rates of other infections dropped," Weinberg explained. "However, the nationwide rates are quite similar to what they were before 2019." Secondly, infections tend to cycle, with some years being worse than others. Doctors often observe spikes in Mycoplasma pneumonia every 3 to 7 years as immunity to the virus wanes, Creech said. "Sometimes you just have a particularly bad year, especially if it's been unnoticed for a while, and now we're seeing more of it," Weinberg added. The third factor is the availability of more advanced tests, known as multiplex tests, which can detect multiple types of viruses and bacteria simultaneously, potentially leading to increased detection of this infection. Mycoplasma pneumoniae are bacteria transmitted through respiratory droplets. Individuals contract them when in proximity to another person's coughs and sneezes, according to the CDC. Consequently, this type of pneumonia can easily spread in crowded environments such as schools, college dormitories, and nursing homes.

These bacteria are also elusive, as they can persist in the body for one to four weeks before causing illness. By the time symptoms emerge, individuals often have little recollection of potential exposures. Mycoplasma infections typically begin with non-specific symptoms, such as a headache, sore throat, low-grade fever, and chills. People often feel unwell but are still mobile, hence the term "walking pneumonia." The cough is usually dry and without phlegm, starting gradually and increasing slowly over two to three weeks until it becomes almost constant. Not all individuals with a Mycoplasma infection require treatment. Weinberg estimates that up to 75% of children and young adults will recover without any therapy. However, the infection can sometimes exacerbate pre-existing conditions like asthma, leading to severe illness. In rare cases, these bacteria can spread beyond the lungs. In the central nervous system, they can infect the meninges of the brain and spinal cord. The bacteria can also infect the nerves of the eyes, as well as those controlling the legs and bladder. Patients with such infections may never develop a cough.