; or (B) by a public health authority of the relevant State or locality that immunization for students in a category in which such student belongs is medically inadvisable. (3) Reasons of conscience exemption Based on an objection in good faith that immunization would violate reasons of conscience. (4) Natural immunity exemption Based on the student having had COVID–19 and acquired natural immunity. (b) Form An objection or certification described in paragraph (1), (2), (3), or (4) of subsection (a) shall be submitted in writing to the chief official of the school by, as applicable, the student or the student’s parent or legal guardian. (c) Definitions In this section: (1) The terms elementary school and secondary school have the meanings given to such terms in section 8101 of the Elementary and Secondary Education Act of 1965 ( 20 U.S.C. 7801 ). (2) The term institution of higher education has the meaning given to such term in section 101 of the Higher Education Act of 1965 ( 20 U.S.C. 1001 ). (3) The term school means a public or private kindergarten, a public or private elementary school or secondary school, or an institution of higher education.