Health library

Feb. 24, 2025—There's an infectious bug that's been on the rise recently. Outbreaks of Mycoplasma pneumoniae—often called walking pneumonia—mostly occur in crowded places, like schools and college dorm rooms.

Wondering what that might mean for you and your family? Here are answers to some common questions about M. pneumoniae, based on information from the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP).

What is walking pneumonia?

Walking pneumonia is a lung infection caused by M. pneumoniae. The infection is marked by milder symptoms than other types of pneumonia. Since people tend to feel well enough to continue their daily routines, it's become known as "walking" pneumonia.

Who usually gets walking pneumonia?

CDC says school-aged children and teenagers are most likely to become infected with the bacteria that cause walking pneumonia.

However, there's recently been a rise in these infections for people of all age groups. Between spring and fall of 2024:

• There was a large increase in cases among children ages 2 to 4 years for the first time, from 1.0% to 7.2% of pneumonia cases.
• Cases more than doubled for children ages 5 to 17 years, from 3.6% to 7.4% of pneumonia cases.
• Among all age groups, the percentage of pneumonia cases caused by M. pneumoniae increased from 0.7% to 3.3%.

Can you spread walking pneumonia?

Yes, walking pneumonia is spread through infected droplets that a person expels. This might happen when they cough or sneeze. Other people then breathe in these infected droplets, which may cause them to become infected too.

How can I protect myself and my family?

Good hygiene is key to preventing walking pneumonia. CDC suggests washing your hands regularly, especially after you cough or sneeze into them. Children should be encouraged to sneeze and cough into a tissue.

Another way to protect yourself is to limit your time around people who have walking pneumonia. Longer exposure times increase your chances of being infected.

What are the symptoms?

Common symptoms of walking pneumonia may include:

• Fever.
• Sore throat.
• Tiredness.
• Cough that gets worse over time.
• Headaches.
• Runny nose.
• Loss of appetite.

For children, symptoms may also include:

• A fever that doesn't improve after five days.
• A cough lasting more than two weeks.
• Fast or difficult breathing.
• Chest pain while breathing.
• Worsening cough.

Children younger than 5 years old may also have diarrhea, vomiting and wheezing.

When is it time to see a doctor?

Contact your doctor if you or your child experiences symptoms that don't go away or get worse over time. The AAP also recommends talking to a doctor if your child has any breathing issues. Doctors will often treat walking pneumonia with antibiotics to help clear it up.

If you suspect you or your child might be having a medical emergency, call 911 or head to the emergency department.

Learn more

Walking pneumonia is just one type of pneumonia that could affect your health. Discover more facts about pneumonia—and how to prevent it—in our Pneumonia health topic center.

Sources

• Centers for Disease Control and Prevention. "Mycoplasma Pneumoniae Infection." https://www.cdc.gov/mycoplasma/media/pdfs/mycoplasma-fact-sheet.pdf.
• Centers for Disease Control and Prevention. "Mycoplasma Pneumoniae Infections Have Been Increasing." https://www.cdc.gov/ncird/whats-new/mycoplasma-pneumoniae-infections-have-been-increasing.html.
• HealthyChildren.org. "Mycoplasma Pneumoniae Infection & Walking Pneumonia." https://www.healthychildren.org/English/health-issues/conditions/chest-lungs/Pages/Mycoplasma-pneumoniae-Infections.aspx.