Hawaii has seen 557 cases of mumps in 2017, and 16 people have suffered from complications.
That's according to the latest figures from the state Health Department.
To tackle the growing outbreak of mumps, the state is recommending more people get vaccinated, even if they've already been vaccinated before.
The large majority of those who have fallen ill — 450 — have been on Oahu. Nearly 60 percent of cases have been in adults.
To help prevent the spread of mumps, the state is recommends the following people born in 1957 or later get a dose of the MMR vaccine now:
Those who last got the vaccine five or more years ago
Those who received two MMR doses 10 or more years ago
Those who don't know if they've been vaccinated
Since children routinely receive their second dose of MMR vaccine before entering kindergarten, the recommendation for the “outbreak MMR dose” applies to adolescents and young adults, the Health Department said.
While mumps spreads easily, it's mostly preventable with a two-dose vaccine.
However, officials say mumps cases this year have been seen in vaccinated and unvaccinated individuals.
Hawaii has seen an influx of mumps cases since March, when the DOH was made aware of nine people with the viral infection.
This year's outbreak is the largest number of cases Hawaii has seen in decades. In all of 2016, Hawaii saw just 10 total cases of mumps.
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.