Three new mumps cases have been confirmed on Oahu, bringing the total number of people sickened to 30, the state Health Department said Friday.
The state also said that it's identified a cluster of cases exposed at the Job Corps Center in Waimanalo.
People who came into contact with the mumps patients have been notified. and the Health Department said it's working closely with the center to "monitor all program participants and staff to identify, control or prevent additional cases."
Job Corps is a career-technical program for youth ages 16 to 24, and serves about 180 clients.
The state has said that at least half of the cases on Oahu so far this year were of individuals who were fully vaccinated.
Despite that, health department officials say the best defense against the disease is a two-dose vaccine.
In all of 2016, the state saw just 10 cases of mumps, which is why the recent uptick in cases on Oahu is concerning.
And it comes as more mumps cases are being seen nationally.
In December, the U.S. Centers for Disease Control and Prevention said the country was in the midst of its worst mumps outbreak in a decade.
From Jan. 1 and April 22 of this year, 42 states and Washington, D.C. reported mumps infections in 2,570 people.
Mumps is highly contagious; symptoms include fever, headache, muscle aches, tiredness, and loss of appetite. Some people with mumps have very mild or no symptoms.
The disease is not considered life-threatening, but there are some lasting side effects, including the swelling of salivary glands and swollen jaws.