California Code, Health and Safety Code - HSC § 1797.186

All persons described in Sections 1797.170, 1797.171, 1797.172, 1797.182, and 1797.183, whether volunteers, partly paid, or fully paid, shall be entitled to prophylactic medical treatment to prevent the onset of disease, provided that the person demonstrates that he or she was exposed, while in the service of the department or unit, to a contagious disease, as listed in Section 2500 of Title 17 of the California Administrative Code, while performing first aid or cardiopulmonary resuscitation services to any person.

Medical treatment under this section shall not affect the provisions of Division 4 (commencing with Section 3200) or Division 5 (commencing with Section 6300) of the Labor Code or the person's right to make a claim for work-related injuries, at the time the contagious disease manifests itself.