Island County Chief Medical Officer Dr. Roger Case believes the end may be in sight to Whidbey Island’s whooping cough epidemic.

“I think by Thursday of this week we will have peaked since the number is growing much more slowly,” Case said.

The total number of Island County whooping cough cases — confirmed, probable or suspect — stands at 59.

Case said he plans to issue a detailed report later this week that sets out how many patients in the 59 cases were fully immunized, partially immunized or had no immunization for pertussis.

“Since the vaccine only stays effective for five or six years, I think that will be significant data to help curtail another outbreak,” he said.

Pertussis is a highly contagious bacterial infection that causes coughing and gagging with little or no fever. An infected person may have coughing episodes that may end in vomiting or cause a “whoop” sound when the person tries to breathe in.

Children under age 1 are the most vulnerable to the disease, which causes the death of more than 300,000 children worldwide each year.

All cases of pertussis should be reported to the Island County Health Department immediately at 360-679-7350.