Walking Pneumonia Is on the Rise

Young children are increasingly being infected with bacteria that can lead to the illness known as walking pneumonia. A hallmark symptom is a cough that starts out dry but eventually produces moderate amounts of thick, non-bloody mucus. The cough can last for weeks.

It’s an unexpected trend, since the bacteria — called Mycoplasma pneumoniae — was so uncommon during the height of the COVID pandemic that one medical journal ran an article suggesting that it may be gone forever. And the increase in illnesses among young children is also unusual, since documented cases usually occur among school-age kids or adolescents.

M pneumoniae typically causes respiratory tract infections and can cause damage to the throat, windpipe, and lungs. Most illnesses are mild, starting with a fever, sore throat, and cough and evolving into what may be viewed as a chest cold. The symptom onset is very gradual.

M pneumoniae often leads to what is known is walking pneumonia — a name given because it is typically less severe than other forms of bacterial pneumonia.

“People with pneumonia caused by M pneumoniae can seem better than expected for someone with a lung infection,” a recent CDC alert stated. “With mild symptoms, people may not stay home or in bed.”

The CDC issued the alert about the bacteria after noticing an increase in emergency room data listing mycoplasma pneumonia as a diagnosis. The increase was first detected in the spring, and cases appear to have peaked in August but remain elevated. The most surprising increase was seen among 2- to 4-year-olds, but a sizable jump was also recorded among 5- to 17-year-olds.

The bacteria spread through respiratory droplets, such as from a cough or sneeze. The long incubation period (1-4 weeks) makes the bacteria prone to causing outbreaks, such as in residence halls, schools, and nursing homes. Coughing symptoms often last a long time, as well, which means outbreaks can persist.

A swab of the nose or throat can test for the bacteria, but this test is not as commonly offered by labs as the tests for flu, COVID, and respiratory syncytial virus. A chest x-ray is sometimes used to check for pneumonia.

Infections from the bacteria can be treated with a class of antibiotics called macrolides, which includes the drug azithromycin. M pneumoniae is resistant to other types of antibiotics, so making an accurate diagnosis is important although challenging since the symptoms can be so similar to other respiratory illnesses. About 10% of people go on to develop a true case of pneumonia.

SOURCES:

CDC: “Mycoplasma Pneumoniae Infections Have Been Increasing,” “Mycoplasma pneumoniae Infection Surveillance and Trends,” “Clinical Features of Mycoplasma pneumoniae Infection.”

The Lancet Microbe: “Mycoplasma pneumoniae: gone forever?”

Yale Medicine: “How is walking pneumonia diagnosed?”