(a) A person serving with or without compensation as a member, director, or trustee, or as an officer of the board without compensation, of any nonprofit hospital or association or of any nonprofit, charitable, or eleemosynary institution or organization or of any local governmental agency, board, authority, or entity shall be immune from civil liability for any act or any omission to act arising out of such service if such person was acting in good faith within the scope of his or her official actions and duties and unless the damage or injury was caused by the willful or wanton misconduct of such person.

(b) As used in this Code section, the term "compensation" shall not include reimbursement for reasonable expenses related to said services.

(c) This Code section shall not affect any immunity of any person arising from any source, whether or not such person may additionally be subject to and possess an immunity provided by this Code section. The immunity provided by this Code section shall be supplemental to any such existing immunity.