Public health officials are making the public aware of a possible measles exposure in York Region. York Region Public Health says anyone who attended the emergency room at Mackenzie Health Hospital in Richmond Hill between 10:30 a.m. and 2:15 p.m. on Tuesday, May 19, may have come into contact with a confirmed case of measles. “Anyone who may have been exposed at Mackenzie Health Hospital Emergency Room should immediately confirm they have two d…