OLYMPIA, Wash. (FOX News) -- The measles outbreak in the Pacific northwest is worsening: 51 confirmed and nine suspected cases. Now there's concern some of the people exposed to the highly contagious disease may have traveled, putting countless others at risk.
"The virus can stay in a room for two hours after someone with the disease has been in there. It can be on surfaces," explained Dr. Phil Huang, Medical Director and Health Authority for Austin Public Health.
Huang describes immunization as one of the greatest public health achievements. According to the Centers for Disease Control, before the vaccine was licensed in the early 1960s, the U.S. would see an average around 500,000 cases of measles every year. That number has dropped to a few hundred, annually.
The overwhelming majority of Washington's new cases have not been immunized, re-sparking debate over the anti-vaccination movement.
"It's my personal belief that I don't believe that we shouldn't be forcing everyone to be vaccinated or refuse them to come to school," said Sean, who opposes vaccinations.
Washington is one of many states with non-medical exemptions. The policy allows children to go to school without getting vaccinated, if their parents have a personal objection, but one state representative is pushing a measure eliminating the exemption, specifically for the measles vaccine. Some parents feel responsibility supersedes personal preference.
"You can't put people at risk because you're late or your opinion. I just don't think that's fair to our general society. If you're going to be in a public school, then you should have to be vaccinated," said Mike Johnston, who supports vaccinations.
At least eight other states have reported measles cases this year. Doctors say one dose of the MMR [measles, mumps, rubela] vaccine is about 93 percent effective. Two doses are about 97 percent effective.