Research and Links

Immunizations (see data for this topic)

Websites with Related Information
Key Reports and Research
County/Regional Reports
More Data Sources For Immunizations

Learn More About This Topic

Why This Topic Is Important
Immunizations are among the most successful and cost-effective preventive health care interventions, protecting millions of children worldwide from serious and potentially fatal infectious diseases (1, 2). For each U.S. birth cohort that receives routine vaccinations, it is estimated that at least 40,000 lives are saved and 20 million illnesses are prevented, at a savings of approximately $70 billion in total societal costs (2). Current immunization schedules recommend that children and adolescents receive vaccinations for diseases such as measles, mumps, whooping cough (pertussis), polio, and varicella (chickenpox) (3). Annual immunization against influenza also is recommended. Vaccinations are important for the protection of the individual child as well as for the protection of others with whom an infected child might come into contact, as most vaccine-preventable diseases are spread through air or direct contact (2, 3).

While measures the number and percentage of children who receive all required immunizations by the time they enter kindergarten, medical experts strongly recommend that children receive a series of vaccinations early in childhood, as infants and toddlers are especially vulnerable to infectious diseases (3).
For more information, see’s Research & Links section.

Sources for this narrative:

1.  U.S. Department of Health and Human Services. (n.d.). Healthy People 2020: Immunization and infectious diseases. Retrieved from:

2.  Ventola, C. L. (2016). Immunization in the United States: Recommendations, barriers, and measures to improve compliance: Part 1: Childhood vaccinations. Pharmacy and Therapeutics, 41(7), 426-436. Retrieved from:

3.  Centers for Disease Control and Prevention. (2019). Immunization schedules. Retrieved from:
Policy Implications
Infectious diseases continue to be a major cause of illness and death in the U.S., despite overall improvements in immunization rates in recent decades (1). Because California law requires proof of vaccinations as a condition of entry into licensed child care, preschool, and public or private elementary and secondary schools, immunization rates are relatively high for children in those settings (2). It is critical to ensure that young children outside of those settings receive routine vaccinations and that adolescents complete all recommended vaccination series (3, 4, 5). While progress has been made, immunization coverage continues to vary by region, socioeconomic status, and other demographic factors, indicating ongoing issues of access and education (3, 4, 6). Public policy can address these issues by helping to ensure that all children have a regular source of high-quality health care, by making vaccinations affordable and accessible, and by supporting a range of strategies with demonstrated effectiveness in increasing immunization rates (3, 5, 7).

Policy and system options to improve immunization rates include:
  • Ensuring that all children have affordable, continuous health insurance coverage and access to a medical home (5)
  • Improving access to vaccinations by reducing costs, expanding clinic accessibility, and offering vaccinations in alternative settings such as pharmacies or day care facilities (3, 7)
  • Supporting efforts to identify and implement effective strategies to improve immunization rates among adolescents, such as text message reminder systems and vaccine administration at school-based locations (5)
  • Equipping health care providers with the tools and training to improve immunization compliance while addressing concerns of vaccine-hesitant parents/adolescents; such interventions may include patient counseling, issuing standing orders to provide vaccinations whenever appropriate, offering combination vaccines, and providing patient reminders (3, 4, 5)
  • Expanding and improving electronic immunization information systems, which contain consolidated, confidential patient vaccination histories and can be used to improve communication across providers, reduce missed opportunities for vaccinations, and send alerts to patients and care teams (3, 8)
  • Supporting public education about the importance of timely immunization and ensuring that educational materials and approaches are tailored to specific groups and are culturally/linguistically appropriate (3, 7)
  • Allocating adequate funding for public health services at the federal, state, and local levels so that agencies can effectively respond to vaccine-preventable disease outbreaks, conduct public education, maintain immunization information systems, and carry out other critical services (9)
For more information, see's Research & Links section or visit the California Immunization Coalition or Shots for School. Also see Policy Implications under's Health Care topic.

Sources for this narrative:

1.  U.S. Department of Health and Human Services. (n.d.). Healthy People 2020: Immunization and infectious diseases. Retrieved from:

2.  Shots for School. (n.d.). Immunization laws. California Department of Public Health. Retrieved from:

3.  Ventola, C. L. (2016). Immunization in the United States: Recommendations, barriers, and measures to improve compliance: Part 1: Childhood vaccinations. Pharmacy and Therapeutics, 41(7), 426-436. Retrieved from:

4.  Hill, H. A., et al. (2017). Vaccination coverage among children aged 19-35 months–United States, 2016. Morbidity and Mortality Weekly Report, 66(43), 1171-1177. Retrieved from:

5.  Bernstein, H. H., et al. (2017). Practical approaches to optimize adolescent immunization. Pediatrics, 139(3), e20164187. Retrieved from:

6.  California Department of Public Health, Immunization Branch. (n.d.). 2018-2019 kindergarten immunization assessment. Retrieved from:

7.  The Community Guide. (2017). What works: Increasing appropriate vaccination. Community Preventive Services Task Force. Retrieved from:

8.  Murthy, N., et al. (2017). Progress in childhood vaccination data in immunization information systems–United States, 2013-2016. Morbidity and Mortality Weekly Report, 66(43), 1178-1181. Retrieved from:

9.  Vaccinate Your Family. (2019). State of the ImmUnion: A report on vaccine-preventable diseases in the U.S. Retrieved from:
How Children Are Faring
In 2019, 94.8% of California kindergartners had received all state-required immunizations by the time they entered school, up from a low of 90.2% in 2014. Across counties with data, the percentage of kindergartners with all required immunizations ranged from more than 99% (Modoc) to less than 72% (Sutter) in 2019.

Statewide, 5.2% of kindergartners were exempt from immunization requirements in 2019: 0.9% had permanent medical exemptions, 1.1% were overdue for one or more required doses, 1.7% were conditional entrants—i.e., children who have temporary medical exemptions or are missing (but not overdue for) required doses—and 1.5% had other types of exemption. The percentage of children entering kindergarten with personal belief exemptions peaked in 2014 at 3.2%. Since 2016, the last year that personal belief exemptions were permitted in California, the number of permanent medical exemptions have increased more than 500%, from 931 in 2016 to 4,812 in 2019.

In 2017, 4,539 cases of vaccine-preventable childhood diseases were reported to the state department of public health, a rate of 11.5 infections per 100,000 Californians. As in previous years, pertussis (whooping cough) accounted for the majority of these cases. Pertussis outbreaks are cyclic, with peaks every three to five years. In California, the rate of pertussis infections, and of vaccine-preventable childhood disease diagnoses overall, peaked in 2010 and 2014.