Though seasonal illnesses like the flu are just starting to gain some traction, there's one respiratory disease that's sickening tons of people across the United States right now: walking pneumonia.
The Centers for Disease Control and Prevention published an alert last month warning people about the uptick in walking pneumonia cases. The infection, which is caused by the bacteria Mycoplasma pneumoniae, damages the lining of the respiratory tract, including the throat, windpipe and lungs. The symptoms, including coughing and wheezing, are typically milder than other lung infections, so people tend to not stay home in bed, hence the nickname walking pneumonia.
"The biggest takeaway is that Mycoplasma infections are generally mild and improve without antibiotics," said Dr. Zachary Hoy, a board-certified pediatric infectious disease specialist at Pediatrix Medical Group in Nashville.
Here's what's going on with the explosion of walking pneumonia cases:
Hoy has seen an increase of walking pneumonia cases at his practice in Tennessee. His patients -- most of whom are kids 5 and older -- have come in with general malaise along with a lingering cough, congestion and, occasionally, a low-grade fever.
The infections are typically mild, but their symptoms last for weeks. "Usually these symptoms have been going on for several days without change or improvement," he said.
Dr. Allen J. Dozor, a pediatric pulmonologist at New York Medical College, said he treats people with walking pneumonia every year, but cases picked up earlier than usual this season.
He first noticed the increased activity in August and continues to see patients week after week. "We always see a surge every fall, and this year is no exception, though our fall surge started early. Two weeks after school starts, my phone rings off the hook."
Though walking pneumonia mostly occurs in young children and adolescents ages 5 to 17, the disease can affect people of all ages. Since late spring, the rate of positive tests increased from 0.7% to 3.3% for all age groups, according to the CDC.
"Although we are seeing a surge of infection with Mycoplasma pneumoniae, the majority of infections are mild," said Dr. Wassim M. Ballan, the division chief of infectious diseases at Phoenix Children's.
The CDC suspects the increased prevalence is a direct result of the immunity gap that occurred after the COVID-19 pandemic.
During the pandemic, protective measures such as face masks and social distancing slowed the spread of many infectious diseases, including walking pneumonia. But "once masking mandates were dropped and we went back to pre-pandemic practices, we started seeing a surge of respiratory pathogens that were almost nonexistent in the first part of the pandemic," Ballan said.
In 2023, walking pneumonia re-emerged, triggering a wave of infections around the world, according to the CDC.
At the same time, our testing methods have improved over the past few years, allowing doctors to catch more cases.
"There are better ways to diagnose M. pneumoniae infections with new diagnostic PCR swabs that may identify cases in 2024 that would not be picked up on testing before 2020," Hoy said.
There may be other factors at play, too. For example, Dozor said climate change is associated with an increase in respiratory infections, and air pollution makes kids more susceptible to respiratory problems like pneumonia.
The bacteria spread through respiratory droplets that an infected person expels into the air when they cough or sneeze. If other people inhale those droplets, they can get infected.
According to the CDC, people who spend a small amount of time around someone with walking pneumonia typically don't get infected. But if you live with or work alongside someone who is sick, there's a higher chance of contracting the disease.
It can take one to four weeks for the bacteria to incubate in your body. So "you could be exposed to someone with Mycoplasma and not get sick for up to four weeks later," Hoy said.
The best way to avoid getting sick? Wash your hands frequently or use hand sanitizer. High-quality face masks absolutely work, Dozor said. But this type of pneumonia is pretty contagious, so, unfortunately, no method is 100% effective.
Most people with walking pneumonia have mild symptoms and recover without antibiotics.
"Symptoms most often worsen for just a few days, level off for a few days and resolve over another few days," Dozor said. As a general rule, the coughing should end within two weeks, he added.
If your symptoms persist or worsen, check in with a health care provider. They can conduct testing and prescribe an antibiotic, such as azithromycin, to speed up your recovery. This is especially useful for people who are immune-comprised or have underlying lung conditions, such as asthma, cystic fibrosis or COPD, as they have a higher risk of developing more severe illnesses, Dozor said.
Finally, you'll want to cover your coughs and sneezes with your arm to avoid passing the bacteria to others. Isolating at home, at least for the first few days of your infection when you are likely most contagious, can reduce transmission, too.
"The very best way to slow the spread, decrease the spread, and protect vulnerable children and adults is to keep them home if they have fever, or even if they are coughing or sneezing significantly," Dozor said.