Central Middle School's principal Anne Marie Murphy alerted students, parents, faculty and staff that several people at the school have been confirmed as having had an infection with the mumps virus.
She said they "attended school for at least one day during the infectious period."
"For reasons of confidentiality we can't get into exact numbers and such because quite frankly, those exact numbers don't really matter. The fact that there are cases matter. The fact that there's spread of disease matters," state epidemiologist Dr. Sarah Park said.
She said it's troubling that one of the new cases involves an adult on Kauai because it's the first mumps case this year outside of Oahu..
"We don't know that this particular case on Kauai is necessarily directly linked to the Oahu cases," she said.
The Health department said some of the just confirmed cases include people at the Job Corps Center in Waimanalo, and health investigators are looking at other potential cases to confirm them or rule them out.
"It's very challenging. It's quite frankly frustrating," Park said.
Vaccination is the best defense.
Mumps is spread through saliva when an infectious person coughs or sneezes. A tender, swollen jaw is an outward symptom.
So far no cases have required a hospital stay.
Dr. Howard Klemmer, emergency room physician at The Queen's Medical Center, said if a person suspects they are infected they should tell their doctor and get tested.
"They should quarantine themselves and keep out of the public where they can spread it to others," he said.
Murphy said Central Middle School is working closely with the Hawaii Department of Health Immunization Branch to try to prevent the contagious illness from spreading further among the school's 429 students and 70 staff members.