Cal. Health & Safety Code § 120390.5

(a) Except as provided in subdivisions (b), (c), and (d), on or after January 1, 2000, the Trustees of the California State University, and the Regents of the University of California shall require the first-time enrollees at those institutions who are 18 years of age or younger to provide proof of full immunization against the hepatitis B virus prior to enrollment.
(b) A person who has not been fully immunized against the hepatitis B virus, as required by subdivision (a), may be admitted by the governing body of any of the institutions of higher education to which subdivision (a) is applicable on condition that, within a designated time period, the person will provide proof of full immunization against hepatitis B.
(c) Immunization of a person shall not be required for admission to an institution of higher education to which subdivision (a) is applicable if any of the following persons files with the governing body of the educational institution a letter or affidavit stating that the immunization is contrary to the beliefs of either of the following:
1. (1) The parent, guardian, or adult who has assumed responsibility for the care and custody of the person seeking admission, if that applicant is a minor who is not emancipated or who is 17 years of age or younger.
2. (2) The person seeking admission, if that applicant is an emancipated minor or is 18 years of age.
(d) If a person seeking enrollment in an institution of higher education to which subdivision (a) is applicable, or the parent or guardian of a person seeking enrollment, files with the governing body a written statement by a physician and surgeon that the physical condition of the person or medical circumstances relating to the person are such that immunization is not considered safe, indicating the specific nature and probable duration of the medical condition or circumstances that contraindicate immunization, that person shall be exempt from the requirements of subdivision (a).