American scientists have identified a new symptom of the Omicron variant in children under five; a “barking” cough that may sound frightening when parents hear it.

According to Dr. Buddy Creech, a pediatric infectious diseases expert at the Vanderbilt University Medical Center in Nashville, some Covid patients in the youngest age group develop “croup-like” coughs which can be identified by a “barking” sound.

That happens, Creech told NBC news, because “little kids’ airways are so narrow that it takes far less inflammation to clog them.” The best way to protect the youngest children, who are not yet eligible for the vaccines, is to “cocoon” them around vaccinated people, he said.

Croup, which is an infection of the vocal cords, windpipe, and bronchial tubes, is a well-known and usually easily treatable disease, so doctors are telling parents not to panic.

While the croup cough may be “scary to hear,” it does not necessarily mean there are any problems with the lungs, said Dr. Amy Edwards, a pediatric infectious diseases expert at the University Hospitals Rainbow Babies and Children’s Hospital in Cleveland.

“The main treatment is to keep the upper airways open and clear until the inflammation subsides,” she said.

Croup can be caused by a number of viruses and normally affects young children aged six months to three years, with most cases occurring in one-year-olds. Most cases of croup are mild and can be treated at home, with symptoms usually improving within 48 hours.

Since the beginning of the pandemic, almost 7.9 million US children have been diagnosed with Covid, according to the American Academy of Pediatrics data.

Coronavirus in kids is generally milder than in adults.