The leading U.S. pediatrician group on Friday urged parents, schools and communities to vaccinate children against measles in the face of an outbreak that began at Disneyland in California in December and has spread to more than 50 people.

The American Academy of Pediatrics said all children should get the vaccine for measles, mumps and rubella between the ages of 12 and 15 months old and again between 4 and 6 years old.

"A family vacation to an amusement park — or a trip to the grocery store, a football game or school — should not result in children becoming sickened by an almost 100 percent preventable disease," Errol Alden, the group's executive director, said in a statement.