PORTLAND, Ore. (KOIN) — Health officials in Clackamas County are warning the public about a growing number of whooping cough cases.

More than 350 cases of the highly contagious respiratory infection have been reported in Oregon in 2019. Officials in Clackamas County confirmed 60 cases over the past several months — more cases than in the past five years.

Whooping cough, or pertussis, is caused by bacteria. Symptoms include uncontrollable, violent coughing fits that can make breathing difficult. The illness gets its name from the gasping, “whooping” sound patients make after coughing fits. People of all ages can catch the disease and transfer it through coughing and sneezing.

High school students are being hit especially hard this winter in Clark County, with the highest number of reported cases at Molalla, West Linn and Lake Oswego high schools. Doctors said the immunity kids receive when they get their final pertussis shot in middle school can wear off.

The biggest concern is for newborns, who don’t start getting vaccinated against pertussis until they’re two months old. They receive their final round of the DTaP vaccine when they reach six months, according to the Centers for Disease Control and Prevention.

“Infants have the highest risk and they’re the most likely to land in the hospital,” said Dr. Paul Cieslak with Oregon Public Health Division. “Occasionally there is a death among infants who get pertussis.”

Pregnant women are urged to get the Tdap vaccine to better protect their babies. Contact your doctor if you didn’t receive a booster shot around the age of 11 or 12.