The CDC posted an alert in October about an increase in Mycoplasma pneumoniae, or "walking pneumonia," infections in the United States, especially among young children.
Similar to influenza and respiratory syncytial virus, M. pneumoniae infections were less common during the pandemic, the CDC reported, but they rebounded in 2023.
From March 31 to Oct. 5, 2024, the proportion of pneumonia-associated ED visits caused by M. pneumoniae increased from 0.5% to 2.1% among all age groups, according to CDC data. The incidence grew from 3.6% to 7.4% and peaked at 9.8% in August among children aged 5 to 17 years. The CDC reported a "notable" increase in cases among young children aged 2 to 4 years, who have not historically been affected by M. pneumoniae, from 1% to 7.2%, with a peak of 10.7% in August.
Healio spoke with Eberechi I. Nwaobasi-Iwuh, MD, a pediatric hospitalist, pediatric infectious diseases physician and division chief of pediatric hospital medicine at Atlantic Health System's Morristown and Overlook Medical Centers in New Jersey, about the recent increase in infections and what physicians should know about it.
Healio: How serious are M. pneumoniae infections, and which groups are most at risk?
Nwaobasi-Iwuh: Usually patients have prolonged coughing, maybe some chest pain, but typically they do not get hospitalized for it, because Mycoplasma infection is self-limiting for most people if their immune system is competent. We see it more in school-aged kids, adolescents and young adults. However, we are seeing it in toddlers and younger school-aged children, which is not typical. We have even been seeing it in some infants, which is unusual as well.
In addition, the kids who have it get a little bit sicker than we have been seeing. Oftentimes, they are coming in after they have been treated with antibiotics that treat typical pneumonia bacteria, and they are still having fevers, worsening symptoms like increasing coughing or difficulty breathing, and when they finally come to the hospital, they require oxygen or they are dehydrated, or they are still having high fevers.
Healio: What should providers be looking for?
Nwaobasi-Iwuh: Mycoplasma does not only cause pneumonia. It can also cause mucocutaneous illness where you get ulcerations and sloughing of the mucosal surfaces in the mouth and sometimes around the eyes. For M. pneumoniae infections, there are not specific symptoms that distinguish it from regular pneumonia. With pneumonia, kids will often have coughing, fever, increased work of breathing where they are breathing faster, or you can see them using more muscles to breathe. Oftentimes, they will start eating and drinking less, getting dehydrated and experience worsening fatigue.
Healio: What should pediatricians do if they suspect their patient has an M. pneumoniae infection?
Nwaobasi-Iwuh: Most of them get better within 24 to 48 hours after starting the appropriate antibiotics, which for Mycoplasma is macrolides. The most common one we use is azithromycin. There are some cases of resistance, so if that patient does not improve within that time frame, sometimes we switch to doxycycline, which usually takes care of it. For most kids, it's usually just a self-limiting kind of respiratory illness that can cause bronchiolitis, bronchitis or walking pneumonia. But we have been seeing some kids who get really sick and are presenting with more severe symptoms than for the typical pneumonia.
Healio: Why do you think there is a surge this year?
Nwaobasi-Iwuh: Anecdotally, since the pandemic, all the typical respiratory illnesses in kids are not following the pre-pandemic patterns anymore. Some viruses are cyclic in that they'll increase in frequency every 5 to 7 years, and I think Mycoplasma may be following that same kind of trend. We are diagnosing it more because we have more consistent testing. Now that we have rapid tests to confirm it and we get the result within a couple of hours, I think we're seeing more cases.
Healio: The CDC alert said there has been a notable uptick in cases among 2- to 4-year-old children. Is this something physicians should be worried about?
Nwaobasi-Iwuh: I think it's something we need to keep an eye out for. This may be partly because we were not typically testing this age group. Now we have these viral panels that can test for many viruses and Mycoplasma as well. They may have been having these symptoms and this illness beforehand, but we were not testing them as readily for it. For most healthy children, they are going to get better, even if you do not do anything. I do not think it is necessarily worrying. I think we are seeing it in a population that we were not suspecting had it in the first place.
Healio: How can we prevent transmission?
Nwaobasi-Iwuh: Just like with other respiratory illnesses, Mycoplasma is spread by droplets. People should stay home if they feel sick or if they are coughing a lot. Good hand-washing and coughing into the elbows help, too. You see outbreaks more in crowded areas like schools, colleges or camps. It can be hard to keep the spread under control. If you have a kid who is coughing and everyone thinks it is just allergies or a little virus but it is actually Mycoplasma, then you have several kids in the class who may be affected.
Healio: Anything else?
Nwaobasi-Iwuh: The longstanding dogma has been that Mycoplasma, or walking pneumonia, was in adolescents and young adults. I think it is important to recognize that it is in pretty much be in every age group now. If a patient seems to have a regular run-of-the-mill pneumonia, or typical virus, give guidance to parents to come back if they are not getting better, so we can decide whether we have to change antibiotics.