Chester County Schools Most Vulnerable to a Measles Outbreak

Each circle represents a kindergarten, seventh-grade or 12th-grade class this year with an MMR vaccination rate below 95%, the threshold experts say is needed to protect a community against widespread outbreaks.
The size of the circle corresponds to the size of the student body.

Schools with fewer than 20 students were excluded for privacy reasons.
Cyber schools were excluded.
Chart: Lizzie Mulvey and John Duchneskie / StaffSource: Pennsylvania Department of Health