California Code, Health and Safety Code - HSC § 1596.7995

(a)(1) Commencing September 1, 2016, a person shall not be employed or volunteer at a day care center if he or she has not been immunized against influenza, pertussis, and measles. Each employee and volunteer shall receive an influenza vaccination between August 1 and December 1 of each year.

(2) If a person meets all other requirements for employment or volunteering, as applicable, but needs additional time to obtain and provide his or her immunization records, the person may be employed or volunteer conditionally for a maximum of 30 days upon signing and submitting a written statement attesting that he or she has been immunized as required.

(1) The person submits a written statement from a licensed physician declaring that because of the person's physical condition or medical circumstances, immunization is not safe.

(2) The person submits a written statement from a licensed physician providing that the person has evidence of current immunity to the diseases described in subdivision (a).

(3) The person submits a written declaration that he or she has declined the influenza vaccination. This exemption applies only to the influenza vaccine.

(4) The person was hired after December 1 of the previous year and before August 1 of the current year. This exemption applies only to the influenza vaccine during the first year of employment or volunteering.