The numbers of vaccine preventable diseases (VPDs) in the United States has declined with the development, administration, and effectiveness of vaccines during the 1970s and 1980s. As the eminent threat of VPDs to the public began to wane, parents started questioning the safety and necessity of vaccines. When parents were given the option of selecting personal belief exemption (PBE) waivers for state mandated immunizations for their incoming kindergarten children, an increase in PBEs and the number of VPD outbreaks began to occur. To counter the growing trend of PBEs, and to prevent outbreaks of VPDs in school settings and communities, California Assembly Bill2109 (AB 2109, 2012) was created to help educate parents about vaccine safety and VPDs. As of January 2014, California Assembly Bill2109 (AB 2109, 2012) mandated that parents seeking PBEs for state mandated immunizations for students entering kindergarten were required to receive education about vaccine safety and risks along with education regarding VPDs by a health care professional (AB 2109, 2012). The purpose of this study was to examine the effectiveness of AB 21 09 by examining data from the top ten most populous counties in California. Data was collected for the 2013-2014, 2014-2015, and 2015- 2016 school years to determine if AB 2109 directly impacted the number of PBEs for incoming kindergartners. This project determined that AB 2109 was significant in decreasing the number 3 of PBEs from the 2013-2014,2014-2015, and 2015-2016 school years by -23.4% in the ten most populous counties in California. Further research beyond this project is necessary to evaluate the continued impact of AB 2109 on PBEs and in decreasing the number of VPD outbreaks throughout California
