We're on pace for the worst measles outbreak in nearly 20 years.
"People think their kids will get it and they'll just have a little cough, no big deal," Michelle Razore said.
Click here to see a breakdown immunization opt-outs by Washington school districts.
The resurgence of pertussis or whooping cough is partly attributed to pockets of unvaccinated children.
The disease is highly contagious and can be life-threatening for babies.
Links to research used in this story
http://www.doh.wa.gov/Newsroom/2013NewsReleases/WashingtonChildVaccinationRatesDecline.aspx
[ http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6236a2.htm ]
[ http://www.fda.gov/BiologicsBloodVaccines/Vaccines/QuestionsaboutVaccines/UCM070430 ]
[ http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/UCM096228 ]
[ http://www.chop.edu/export/download/pdfs/articles/vaccine-education-center/aluminum.pdf ]
[ http://www.cdc.gov/ncbddd/autism/data.html ]
[ http://www.thelancet.com/journals/lancet/article/PIIS0140673604167159/fulltext ]
[ http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5738a5.htm ]
[ http://www.jpeds.com/content/JPEDSDeStefano ]
Special thanks to Dr. Jeff Duchin, Chief of Epidemiology King County Public Health.