But measles is still a big problem in other parts of the world. Travelers infected overseas can bring the virus into the country and spread it, causing periodic outbreaks.
In the USA last year, there were 17 outbreaks and about 350 cases of measles. However, state laws allowing parents to opt out of mandatory vaccinations quickly began eroding those statistics, leading to outbreaks across the nation.
The first known patients in this outbreak sought medical care on December 31, but officials don't know if other people may have gotten sick before that and did not seek treatment, the AP reported.
The threat also spread in the past few days; Deschutes County officials say someone visiting Bend on January 19 and 20 may have brought measles with them. Clark County Public Health Officer Alan Melnick told the paper that if vaccination rates don't go up in the area, the state could be seeing more incidents like this one moving forward.
Vaccination rates in OR and Southwest Washington, where measles first broke out, are comparatively low. Between one and three cases out of every 1,000 are fatal, he said.
Clark County has already spent more than $100,000 trying to contain the outbreak, and staff is being pulled from other duties, including restaurant inspections, he said. "These costs could have been prevented if we had everybody vaccinated". OR also has a high nonmedical exemption rate for vaccinations-one 2018 state analysis found a rate among kindergarteners of 7.5 percent, with the number for K-12 students climbing as high as 10 percent in some counties. Herd immunity happens when unvaccinated individuals are protected from infection because nearly everyone around them has been vaccinated and is immune to a disease. Measles was declared eliminated - defined by absence of continuous disease transmission for greater than 12 months - from the United States in 2000. Most recent data available here.
Two doses of the vaccine in childhood are 97 percent effective and provide lifetime immunity. One dose is about 93 percent effective. The current law in place allows parents to decline immunization for children based on "philosophical or personal objections", health risks as confirmed by a licensed physician, or religious beliefs.
"We want everybody to be at 95 percent coverage or higher". Measles symptoms tend to manifest seven to 21 days after exposure. The disease is contagious from approximately four days before the characteristic rash appears to four days after the rash appears. Infected droplets from the individual with measles can spray into the air or land on a surface, where they remain active and contagious for hours. Ninety percent of people exposed to measles who have not been vaccinated will get it, public health officials said.
The measles is highly contagious and can be deadly if small kids get it.
Earlier this week, authorities were successful in identifying several people who had been exposed but were not sick yet.
In the Clark County outbreak, people who have contracted the virus have visited community hubs like schools, churches, and doctor's offices, along with a Costco, an Ikea, a Dollar Store and other locations, according to Clark County Public Health.
Measles is caused by a virus that presents as fever, cough, runny nose and red eyes, followed by full body rash of tiny red spots, according to the CDC. People who are not killed by the disease may still develop serious, lifelong complications.