Measles Cases Mount In Pacific Northwest Outbreak

A measles outbreak in Washington state prompted Gov. Jay Inslee to declare a state of emergency on Jan. 25.

As of Thursday, 55 cases have been confirmed this year, most of them in unvaccinated children under age 10. The outbreak's epicenter is Clark County, Wash., just north of Portland, Ore.

Measles is a highly contagious disease that can result in brain damage, deafness and, in rare cases, death. In 2000, measles was declared eliminated from the United States, thanks to widespread vaccination campaigns.

Yet cases have popped up in 11 states so far this winter, and the Centers for Disease Control and Prevention is tracking three outbreaks (defined as three or more confirmed cases) in New York City, New York state and Washington state.

Read Gov. Inslee's Declaration Of A Public Health Emergency Amid The Measles Outbreak
Vaccination rates around 90 to 95 percent are generally enough to prevent an outbreak, according to health officials, but rates have fallen across the United States.

One factor is the spread of misinformation about the measles vaccine, which is considered safe and effective by health authorities.

Vaccination rates in the Pacific Northwest are among the lowest in the nation. While all school-age children are required to receive the MMR vaccine, which protects against measles, mumps and rubella, Washington is among the 17 states that allow "philosophical exemptions," meaning a parent can excuse a child from being vaccinated for virtually any reason.