Duties of school physicians shall include the vaccination of children of indigent parents, official re-vaccination of children having temporary vaccination certificates, physical examination of children incident to the issuance of employment certificates as required by the provisions of the Child Labor Act, approval of the return of pupils who have been absent due to a contagious disease or suspected contagious disease, and such other duties as may be required by the board of school directors not inconsistent with the rules and regulations of the Secretary of Health.