SEATTLE — In Clark County, home to one of the nation’s largest measles outbreaks, the effects go far beyond the 71 confirmed cases.

The Seattle Times reported more than 800 students considered exposed to the highly contagious disease have been ordered to stay away from classrooms for up to three weeks, disrupting their education.

Since January, field trips, after-school activities and an assembly honoring Martin Luther King Jr. have been canceled or postponed. Some students are doing homework off prepared handouts; others are using school-issued laptops to keep up.

If one child in a school is diagnosed, all are considered exposed — and any student whose parents cannot prove their child was vaccinated is kept away.

More than a dozen Clark County schools — most in Vancouver — had students sit out of class after a directive from health officials.