WINDHAM, NH – Two students in Windham, New Hampshire have reportedly been diagnosed with pertussis, or whooping cough.

The students are enrolled at Golden Brook School and Center School in Windham, according to the Eagle Tribune.

A letter was sent home notifying parents of kids who may have been exposed.

According to the U.S. National Library of Medicine, whooping cough is highly contagious, and causes uncontrollable, violent coughing. The coughing can make it hard to breathe. A deep “whooping” sound is often heard when the patient tries to take a breath.

A vaccine does exist. However, it’s not 100 percent effective.