Transcript for Measles outbreak linked to anti-vaccination movement
a measles outbreak in the pacific northwest. There are now 23 confirmed cases, most of them affecting children ten years and under and most of those children were not vaccinated. ABC's janai Norman is here with the details on this story. Good morning, janai. Good morning, so officials have declared a public health emergency in Clark county near the washington/oregon border, the epicenter of the newest outbreak. Children particularly hard hit. Of the 23 cases 18 are in children 10 years and under. Officials have already identified dozens of public places where people may have been exposed and say part of the cause for concern is the low vaccination rate in the the area. It comes after the CDC reported 349 confirmed cases across 26 states last year. The second most in nearly two decades. How contagious is this? Okay, so consider this, on average one person with measles can infect 12 to 18 others and the infectious droplets can remain in the air for about two hours so that means you can become infected without personal contact and that is why officials are so strongly urging everyone, get vaccinated. The CDC says it is 97% effective on those who get the recommended two doses and can help even 72 hours after exposure so a couple days after being exposed you can still be covered. If you don't get a vaccination you're putting others at risk. That's the point. I think we need to remember
This transcript has been automatically generated and may not be 100% accurate.