A student shall not attend classes or other school-sponsored activities while afflicted with any contagious or infectious disease, or while liable to transmit such a disease after being exposed, unless the Board or its designee has determined, based on medical evidence, that:
1.) The student is no longer infected or liable to transmit the disease; or
2.) The student is afflicted with a chronic infectious disease which poses little risk of transmission in the school environment with reasonable precautions.