What is Mycoplasma Pneumoniae? 5 Things You Need to Know

“With a lot of these infections, the natural history is that you get infected, you get some transient boost in your immunity, and then that immunity wanes over a period of years, and then over time, you’re susceptible until the next time you’re exposed. And so it may very well be that we’re seeing a sort of rebound to some of these infections that people haven’t seen in a few years because of all the COVID precautions,” she says.

The CDC says Mycoplasma pneumoniae began to re-emerge globally in 2023 “after a prolonged period of low incidence of infections since the start of the COVID-19 pandemic.”

3. It can cause a milder ‘walking pneumonia’

Mycoplasma pneumoniae infections are most common in children and young adults, but anyone can be affected, the CDC says. Typically, symptoms are mild and may include a sore throat, headache, fatigue, fever, a cough and sometimes a rash. But Mycoplasma pneumoniae can cause pneumonia, or inflammation of the lungs, and is the most common cause of “walking pneumonia” in the U.S. (Walking pneumonia, also called atypical pneumonia, is a milder form of the disease that usually doesn’t require bed rest, though symptoms tend to be “a little bit more lingering,” Thielen says.)

Sometimes an infection can turn severe and lead to more serious pneumonia, asthma attacks, kidney problems and other health issues. People at higher risk for a severe case of Mycoplasma pneumoniae include those with an underlying lung condition, individuals with a weakened immune system and people who are recouping from a respiratory illness, the CDC says.

Most people recover from a Mycoplasma pneumoniae infection without requiring a prescription from the doctor. However, specific types of antibiotics can be used to treat pneumonia caused by the bacterium.

4. Staying up to date on vaccines can help  

Like COVID-19, influenza and many other common respiratory illnesses, Mycoplasma pneumoniae is spread through small droplets produced when an infected person coughs or sneezes. This means most of us are already familiar with the actions that can help prevent an infection, such as staying home when you’re sick and washing your hands often. “All the same things hold true,” Pekosz says, referring to COVID-19 and flu precautions.   

Wearing a mask when you’re in a crowded environment can also help reduce your risk. Another thing: Although there’s not a vaccine that can defend against Mycoplasma pneumoniae, getting vaccinated for flu, COVID-19 and RSV can be protective.

“Sometimes people get a viral infection first and then go on to get bacterial infections after. The viral infection sort of opens the door and then lets these bacterial infections in,” Thielen says. Doctors refer to this as a secondary infection. “So I think anything people can do to generally protect the respiratory health and protect themselves from other types of infections that we see this time of year is helpful,” she adds.

Plus, COVID-19, flu and RSV can all cause pneumonia, too. And don’t forget about Streptococcus pneumoniae, or pneumococcus — the most common cause of bacterial pneumonia in the U.S. “And older adults are eligible for that vaccine as well,” Thielen says.

The CDC recently updated its pneumococcal vaccine recommendations to say adults 50 and older should get the shot. Previous recommendations were for people 65-plus.

5. Precautions, not panic 

With reports of Mycoplasma pneumoniae cases on the rise, now is not a time to panic, Thielen says, but instead to remember all the precautions that can help protect you from this bug and others circulating this time of year.

“There are some basic techniques that work pretty well against many respiratory pathogens,” Thielen says. “I say do the best you can as much of the time as you can during this high-risk season, and hopefully that’ll bring the burden of disease down for all of us.”

Editor's note: This story, first published Dec. 8, 2023, has been updated to include new information.