Why does it increase in children?

• US Centers for Disease Control Announces Increase in Pediatric Cases of “Walking Pneumonia”
• An increase happens “every few years,” says Dr. Matthew Isaac Harris, a pediatric emergency medicine physician at New York-based Northwell Health, tells PEOPLE
• Dr. Harris says the infection is “very treatable” with antibiotics, and advised parents to skip over-the-counter cough medicine

Cases of atypical pneumonia (also known as “walking pneumonia”) – which is a lung infection caused by the bacterium Mycoplasma pneumoniae – are on the rise in the United States, with cases in children rising so sharply that the US Centers for Disease Control (CDC) issued a warning Friday, Oct. 18

But what exactly is walking pneumonia?

“Progressive pneumonia is a layman’s term for a type of pneumonia, which in medical terms we call atypical pneumonia. It just means that they (the patients) don’t follow the kind of normal course of fever, cough and acute exacerbation,” Dr. Matthew Isaac Harris, a pediatric emergency physician and medical director of Critical Care Transport at New York-based Northwell Health, tells PEOPLE.

“They look better clinically than the average bear,” he explains, adding that these less severe symptoms can lead to a delayed diagnosis.

“They might have a week to two weeks of worsening cough. Sometimes it’s some fever,” says Dr. Harris. “They don’t have the classic three-to-four days of high fever, productive cough that you might see in the more classic pneumonia.”

But while the cases are increasing, “it is not a unique year,” adds the doctor. “We have these waves of mycoplasma pneumonia every few years.”

As for why it spreads among children, he explains, “They’re constantly coughing in small classrooms or in preschools or in playgroups. The things that put kids at higher risk is just their exposure to other kids who are constantly coughing in their closeness.”

“The spike this year happens every few years,” he explained. “It’s very contagious.”

Never miss a story – sign up PEOPLE’s free daily newsletter to keep you updated on the best of what PEOPLE has to offer, from celebrity news to compelling human interest stories.

The good news, says Dr. Harris told PEOPLE, is that it’s “very, very treatable” with antibiotics — generally azithromycin, which he explained is “more commonly known as the Z-pack.”

“It’s once a day for five days, so it’s not the time you have to fight with your child three times a day trying to get a large amount of antibiotics in,” he tells PEOPLE.

And regardless of how quickly your child recovers, “it’s vitally important to complete the entire course.”

Dr. However, Harris also advises parents to avoid over-the-counter cough medicines.

“Children tolerate honey very well. Honey is a natural anti-cough medicine. I would encourage parents not to use cough medicine for children that is not approved by their pediatrician.”

Although the CDC issued a warning, Dr. Harris “we are at the stage where we have to be aware.”

“Watch out for these signs of respiratory distress, which are really common in younger kids under 2. Older kids will tell you they’re not feeling well.”

He advised parents to watch for symptoms, including “breathing faster, not drinking as much, maybe not peeing as much because they’re not drinking.”

“We don’t want parents to run to the pediatrician every time their child has a cough,” the doctor says, before noting that “it’s really just the cough that slowly worsens and has a low-grade fever after a week to 10 days, and that doesn’t get better. It’s really time to see your pediatrician.”