In 2015, approximately 48 states, the district of columbia, american samoa, guam, the northern mariana islands, puerto rico, and the virgin islands had statutes requiring mandated reporting of abuse by in the medical, social service, school, and law enforcement fields.

"Professionals" would seem to be the word to fill in the blank in your sentence.

The mandate specifically lists professions that have frequent contact or interaction with children, such as the professions or fields that you listed in the statement:  Medical workers, social workers, teachers or other school officials, law enforcement officers.  To that list you could also add childcare providers, and therapists or counselors.  Some states also would require workers and even volunteers in programs that provide organized activities for children, such as camps or recreation centers.