https://www.hhs.gov/hipaa/for-professionals/faq/517/does-hipaa-allow-a-health-care-provider-to-disclose-information-to-a-school-nurse/index.html (working link)
Does the HIPAA Privacy Rule allow a health care provider to disclose protected health information (PHI) about a student to a school nurse or physician?
Yes. The
HIPAA Privacy Rule allows covered health care providers to disclose PHI about students to school nurses, physicians, or other health care providers for treatment purposes, without the authorization of the student or student’s parent. For example, a student’s primary care physician may discuss the student’s medication and other health care needs with a school nurse who will administer the student’s medication and provide care to the student while the student is at school. In addition, a covered health care provider may disclose proof of a student's immunizations directly to a school nurse or other person designated by the school to receive immunization records if the school is required by State or other law to have such proof prior to admitting the student, and a parent, guardian, or other person acting
in loco parentis has agreed to the disclosure. See 45 CFR 164.512(b)(1)(vi).