Employment that an intern performs is not covered employment if: the employer is a hospital; and the intern has completed a 4-year course in a medical school that is chartered or approved under State law. Employment that a patient of a hospital performs for the hospital is not covered employment. Employment that a student nurse performs is not covered employment if: the employer is a hospital or training school for nurses; and the student nurse is enrolled in and regularly attending classes in a training school for nurses that is chartered or approved under State law.