Public Health – Seattle & King County has reported nine confirmed or probable mumps cases in King County, all in the Auburn area, with an additional five cases being investigated.

Mumps virus/CDC
Mumps virus/CDC

Eight of the nine mumps cases are among children between 8-17 years of age, with one adult case, 23 years of age. No one has been hospitalized and all of the children have recovered. All of the children were up-to-date on MMR vaccine.

Because mumps is highly contagious, mumps outbreaks can occur even in vaccinated populations because a minority of people don’t respond to the vaccine and remain susceptible.

“Vaccination provides very good protection, but not 100%.  MMR vaccine is on average 85% protective for mumps after two doses,” said Dr. Jeff Duchin, Health Officer for Public Health – Seattle & King County. “85% protection is very good and vaccination is the most important step to protect children and adults against mumps, which can be a painful experience, and its uncommon serious complications including meningitis and, inflammation of the brain, testes, ovaries, and other organs.”

Mumps is an illness caused by a virus that can cause fever, headache, and swelling of the cheeks and jaw. Most people recover from mumps in a few weeks. In rare cases, mumps can lead to more serious complications that may require hospitalization, including inflammation of the brain and spinal cord and deafness. Up to 30% of people with mumps infection will have no symptoms.