Health officials in Chester County, Pennsylvania, have issued warnings regarding possible measles exposure following a confirmed case at Oxford Area High School, which has resulted in its closure. The situation has escalated with additional health advisories issued for several stores in the area where exposure may have occurred. The local school district is reviewing vaccination records and has implemented measures restricting unvaccinated students from attending school during this outbreak. Parents are urged to stay informed as the health department continues to monitor the situation closely.