410 ILCS 235/6

A child shall not be required to receive a pertussis vaccine as a condition for admission to a public or private school if the child's health care provider states in writing that the vaccine is medically contraindicated pursuant to subsection (b)(1) of Section 3 of this Act and the reasons for the medical contradictions, or if his parent or guardian has submitted a signed statement to school officials stating an objection to the vaccination on religious grounds.