INDIANAPOLIS (WISH) — Walking pneumonia cases in central Indiana have seen a steep increase in recent weeks, local physicians say.

“But what we’ve seen this summer, starting in July and August, was an explosion in the number of cases,” said Dr. John Christenson, associate medical director of infection prevention at Riley Hospital for Children. “Some require admissions to intensive care units. Children die, adults die .. sometimes it invades the brain and it can cause an infection there.”

Walking pneumonia is generally considered less severe than pneumonia, but can have lasting impacts if not caught early on. The disease is caused by mycoplasma pneumoniae, which can damage the lining of the respiratory tract, according to the CDC.

It is spread through droplets released when someone coughs or sneezes.

“Symptoms can begin mildly with sore throat, cough, or chest pain,” Christenson said.

About two million people are diagnosed with the disease each year. This year is different, though.

While it’s common for young children and adolescents to be impacted, small children born during the Covid-19 lockdown are seeing a surge in cases.

The CDC said diagnoses in kids between two and four years old jumped from 1% to 7.2% over a six-month time span this year.

“We saw a rebound after Covid,” Christenson said.

During lockdown, people were wearing masks, staying home, and were not at school and work.

“What happened was a lot of people who could acquire an infection around that time, didn’t,” Christenson said. “So, now they’re all susceptible. You bring in a new germ or an old germ into an environment and it spreads like wildfire.”

Several local schools have seen an increase in students, asking parents to be on the lookout for symptoms and to take their child to a physician if needed.

As holiday gatherings begin, Christenson is heeding a similar call, especially in severe cases.

“That’s when you need to take them to their healthcare professional to have them seen, and in some cases, get X-rays,” Christenson said.

Additionally, Christenson said it is important to make sure families are up-to-date on all vaccinations.