The number of mumps cases in Pierce County is growing, according to the Tacoma-Pierce County Health Department.
There are now three confirmed cases and six probable cases.
The health department said about half of the cases involve children 17 and under, and 78 percent of the people infected have up to date mumps vaccinations.
All of the Pierce County cases stem from an outbreak in Auburn and the school district there that also has spread to Spokane County and Yakima County. No transmission of the illness has happened in Pierce County, the health department said.
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King County has reported 19 confirmed cases and 64 probable, 67 of which are in Auburn. Most of the infected are kids and 70 percent of the people with mumps have up to date vaccines.
The vaccine usually works in 88 percent of the population, health officials said.
Mumps is a highly contagious viral illness that can be spread through face-to-face contact, coughing, sneezing or spraying saliva while talking. It can last a week to 10 days.
Symptoms include headache, fever, muscle aches, tiredness and loss of appetite.
People can transmit mumps one to two days before they have its signature symptoms of a swollen jaw or puffy cheeks, according to the health department.
More information about mumps can be found at tpchd.org/mumps.
Stacia Glenn: 253-597-8653