An unexpected surge in respiratory infections caused by the bacteria Mycoplasma pneumoniae has health officials and doctors on high alert in the United States, particularly as cases spike among young children. This bacterium, responsible for a mild form of pneumonia often referred to as “walking pneumonia,” has been on the rise since late spring, with emergency rooms seeing increased numbers of young patients presenting persistent coughs and respiratory issues.
SOURCE: Waites KB, Talkington DF. Mycoplasma pneumoniae and its role as a human pathogen. Clin Microbiol Rev. 2004;17:697–728.
Typically mild in nature, Mycoplasma pneumoniae infections can mimic symptoms of a chest cold, with gradual onset signs like fever, cough, and sore throat. Yet for some children, these symptoms can progress to pneumonia, particularly a less severe type that allows the patient to remain active, giving rise to the term “walking pneumonia.”
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Diagnosis and Treatment Challenges
Historically, diagnosing M. pneumoniae has been challenging. Standard bacterial cultures don’t grow the bacterium well, often complicating detection. But as better diagnostic tools emerge, such as rapid tests, doctors are now able to identify this infection more quickly, allowing them to prescribe more effective treatments earlier.
When M. pneumoniae is identified, healthcare providers often treat it with macrolide antibiotics, like azithromycin, as first-line options. Unlike amoxicillin and penicillin, which are commonly used for bacterial infections, these antibiotics specifically target M. pneumoniae. CDC officials have cautioned providers to consider M. pneumoniae as a possible cause of persistent respiratory symptoms, especially in children not responding to common antibiotics.
CDC’s Vigilance and Monitoring Efforts
The Centers for Disease Control and Prevention (CDC) has been closely tracking M. pneumoniae infections. This year, their data shows a notable increase in diagnoses, especially among children ages 2–4—a group historically less affected by this bacterium.
The CDC’s data indicates that in August 2024, 7.2% of emergency department visits among children aged 2–4 for pneumonia showed a diagnosis of M. pneumoniae, up from 1% in April. Among older children, the percentage nearly doubled within the same timeframe.
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The CDC is monitoring the situation through a mix of hospital discharge records and laboratory reports, with an eye on both demographic trends and antibiotic resistance. Public health alerts have also been issued to ensure healthcare professionals remain aware of the symptoms and treatment protocols for M. pneumoniae infections.
Spread and Prevention
Spread primarily through respiratory droplets, M. pneumoniae often thrives in crowded settings such as schools and daycares. Once an individual is infected, they can carry the bacterium in their respiratory tract for months, extending the risk of spread. Although hand hygiene, mask-wearing, and cough etiquette can reduce transmission, the bacterium’s prolonged incubation period—lasting up to four weeks—poses additional containment challenges.
While the risk of transmission is lower with brief encounters, those in close contact with an infected individual face a higher likelihood of contracting the illness. Children with underlying respiratory conditions like asthma are especially vulnerable and may experience more severe symptoms, potentially requiring hospital care.
Global Trends and Contributing Factors
The resurgence of M. pneumoniae cases in 2023 wasn’t isolated to the United States. Countries including China, Denmark, and France also reported spikes. Experts suggest that this rise may be a return to pre-pandemic infection levels, as the lockdowns and social distancing measures during COVID-19 had temporarily suppressed respiratory infections worldwide. Additionally, M. pneumoniae cycles in prevalence every few years, likely due to waning immunity in the population.
Pediatric infectious disease specialists, like Dr. Geoffrey Weinberg from the University of Rochester, attribute the heightened numbers to the bacteria’s natural epidemiological cycle. Dr. Buddy Creech from Vanderbilt University further emphasized that regular M. pneumoniae surges every three to seven years are common, driven by fluctuating community immunity.
Looking Ahead: Staying Informed and Prepared
With this unexpected rise in M. pneumoniae cases, health experts encourage parents to be vigilant for symptoms like prolonged cough, fever, or difficulty breathing in children. If symptoms persist, seeking medical advice can ensure timely diagnosis and treatment, especially for children at higher risk of complications. As flu season approaches, health officials also stress the importance of routine vaccinations, which, while not preventing M. pneumoniae, can help mitigate other respiratory illnesses that may add stress to healthcare systems.
By raising awareness, the CDC hopes to help families and healthcare providers alike stay prepared for and effectively manage the impact of Mycoplasma pneumoniae as it continues to affect communities across the nation.
