Julia Belluz put up a couple of articles on the anti vaccine movement. A problem that apparently is not going away any time soon: vox.com/anti-vaccine-movement-trump and vox.com/robert-de-niro-rfk-jr-vaccine-press-conference.
The mumps has broken out this winter in Washington State with 404 cases thus far with King County and Spokane County with the majority of cases. (http://www.doh.wa.gov/YouandYourFamily/IllnessandDisease/Mumps/MumpsOutbreak). The cases in Spokane County have been growing and the Health District in Spokane County has ordered non vaccinated children to stay home in an effort to curb the outbreak.
Vaccine rates in Washington State 2006-2007
New England Journal of Medicine