CA’s New Vaccine Law: Which Counties Have Yet to Achieve Herd Immunity?
Last month, California’s new mandatory child vaccination law, SB 277, took effect. The law helps enforce the Department of Education’s requirement that all California children attending public and private schools receive a series of vaccines, unless they have a medical exemption. Inspired by the 2014 measles outbreak at Disneyland and the state’s 2010 and 2014 whooping cough outbreaks, SB 277 prohibits parents from citing personal beliefs or religion as reasons to not vaccinate their children.
To better understand how SB 277 will affect the health of children in California, Kidsdata has released the newest data available on student immunizations for the 2015-2016 school year. Depending on the effectiveness of the vaccine, and how long immunization will last, California public health officials recommend vaccination rates of between 80-94 percent in order to achieve community immunity (PDF), also known as “herd immunity.” Diseases such as polio, which is less contagious, have a lower threshold, while diseases such as measles, which is highly contagious, require a 94 percent threshold in order to protect those most at risk.
Between 2011 and 2016, the state showed a modest 2 percent rise in the percent of kindergartners who had all required immunizations, reaching 93 percent in 2016. When broken down by county, however, geographic differences become clear. At 100 percent, Sierra County led the 26 counties with immunization rates of 94 percent or higher. Three counties had rates lower than 80 percent: Tuolomne, Nevada, and Trinity.
The Gold Country counties of Sierra, Calaveras, and Mariposa each saw a rise of at least 8 percentage points since 2011, bringing them closer to recommended thresholds. On the other end of the spectrum, Amador, Modoc, and Trinity Counties (one in Gold Country, and two in California’s far north) all saw drops of at least six percentage points, moving their populations further from community immunity.
Immunizations are among the most successful and cost-effective preventive health care interventions, helping millions of children in the U.S. and internationally avoid contracting numerous serious and potentially fatal infectious diseases.
Related Data (by State, County & School District):
California Dept. of Public Health, Immunization Branch
California Immunization Coalition
Legislative Challenges to School Immunization Mandates: 2009-2012, JAMA: The Journal of the American Medical Association
Solutions to Reducing Vaccine-Preventable Childhood Diseases, Population Reference Bureau
Vaccines Do Not Cause Autism, Centers for Disease Control and Prevention
Immunization Rates in Child Care and Schools, California Dept. of Public Health, Immunization Branch
Ever wondered who runs Kidsdata? Kidsdata is a program of the Palo Alto, CA-based Lucile Packard Foundation for Children's Health, which promotes the health and well being of children in California.
Kindergartners with All Required Immunizations