The California Department of Public Health (CDPH) is seeking to replace the current immunization information system (IIS), CAIR2, with a more robust solution to enhance handling of large-scale vaccination events. The goal of the project is to enhance California's resilience to current and emerging health threats for our constituents by allowing the CDPH Immunization Branch to better handle vaccination events of both small and large scale.

​The California Department of Public Health (CDPH), which resides in the California Health and Human Services Agency (CHHS), is organized into five centers dedicated to different aspects of public health policy and programs. One of those centers, the Center for Infectious Diseases (CID), protects the people in California from the threat of preventable infectious diseases and assists those living with an infectious disease in securing prompt and appropriate access to health care, medications, and associated support services. The Center for Infectious Diseases operates programs through four divisions and offices: Division of Communicable Disease Control (DCDC), Office of Binational Border Health (OBBH), Office of Refugee Health, and Office of Aids (OA).  

The Division of Communicable Disease Control (DCDC) works to promptly identify, prevent and control infectious diseases that pose a threat to public health, including emerging and re-emerging infectious diseases, vaccine-preventable agents, bacterial toxins, bioterrorism, and pandemics. DCDC encompasses six programs and branches: Immunization Branch (IZB), Communicable Disease Emergency Response Program, Infectious Disease Branch, Infectious Diseases Laboratory Branch, Sexually Transmitted Diseases Control Branch, and Tuberculosis Control Branch. 

The mission of the Immunization Branch (IZB) is to provide leadership and support to public and private sector efforts to protect the population against vaccine-preventable diseases. The CDPH IZB tracks and monitors immunizations and diseases throughout the state; works in partnership with health officials, health care providers, and the public to administer state and national immunization efforts; and provides epidemiological assessments and analyses. CDPH uses immunization data for epidemiological assessments and mandatory reporting.

IZB includes the Registry and Assessments Section, which is responsible for, and provides oversight for, CAIR2, California’s statewide Immunization Information System (IIS). Immunization information systems or IIS are an effective tool in helping the IZB achieve its mission. The complexity of the evolving immunization schedule, the migration of children among health care providers through childhood, and the constraints of traditional medical record systems make tracking children’s immunizations difficult. These factors contribute to both the lack of immunizations and to over-immunization, which occurs when records cannot be found to verify prior vaccinations. Many of these issues are especially difficult in California given its size and diversity. IIS are confidential, population-based, computerized information systems used to capture, store, track, and consolidate vaccination data from multiple sources and serve as an important tool in preventing and controlling vaccine preventable diseases and in increasing and sustaining vaccination coverage rates.

Monitoring of immunization records assist in the vital effort to maintain and improve vaccine safety. Knowing the safety profile of vaccines is essential to accurately assess the risks and benefits of vaccination, to formulate appropriate vaccine recommendations, and to address public concerns. 

The original CAIR system (CAIR1) was a collaboration of registries throughout the state of California. The vast majority of Californian counties used the CAIR1 Software Application and were called CAIR Software Regions.⁴ At that time, the remaining 10 counties used other software products. These included San Diego County which operated the San Diego Immunization Registry (SDIR), Imperial County which utilized its own software), and then eight counties in the central part of the state that used the RIDE/Healthy Futures software (San Joaquin County, Amador County, Calaveras County, Alpine County, Stanislaus County, Tuolumne County, Merced County, and Mariposa County). 

The CAIR2 system was launched in three phases and formally accepted as complete on April 30, 2017. As a result of CAIR2, patient records and vaccine doses containing Health Leven Seven (HL7) messages could be directly incorporated and there was a reduction in the time to produce cross-regional or statewide Healthcare Effectiveness Data and Information Sets (HEDIS) patient match reports.⁵ By the end of the project, eight of the original 10 regions had joined CAIR2 and there were only two independent regions remaining.  

Key attributes of CAIR2 include: 

• CAIR2 is internet accessible. 
• 50 of 58 CA counties participate counties accounting for 96 percent of California’s population. 
• Has secure, user interface allowing users to add/edit patients and vaccine doses, manage vaccine inventory, schedule patient immunizations according to the Advisory Committee on Immunization Practices (ACIP) recommendations, and run a variety of reports, including on aggregate and individual patients.   
• Both independent regional registries agreed in 2019 to send patient and vaccine doses updates to CAIR2 so that all state immunization data will reside in the CAIR2 ‘hub’ though this had not yet been implemented because of the COVID-10 pandemic.  In June 2021, SD county made the decision to move to CAIR2 with a target date of March 2022. 
• Supports electronic messaging in the standard HL7 format, including both vaccine updates (VXU message type) and query/responses (QBP message type) between providers and the IIS. Currently, about nearly 10,000 locations submitting electronic data, and >3,000 submitting electronic queries.  

CAIR2, currently maintained by CDPH’s Immunization Branch and a third-party vendor, is recognized and funded by CDC as the official state IIS. 

In early 2020, the COVID-19 pandemic began, and the Department shifted priorities to address COVID-related efforts. 

Over the course of the last year, the COVID-19 pandemic has highlighted the significant weaknesses and limitations with the CAIR2 system in handling large-scale vaccination events. Among the limitations are: 

• Inability to support high volumes of incoming HL7 vaccine updates (VXU message type) and query/responses (QBP message type) messages.   
• Suboptimal patient matching leading to excessive generation of duplicate patients, resulting in incomplete upload of patient vaccine doses. 
• Lack of robust reporting capacity for system users, including counties and health plans. 
• Poorly performing dose replacement (historical vs. administered doses) and record update logic.  
• Lacks configurable vaccine recommendation feature. 
• Inability to un-merge mistakenly merged patient records. 

California has the opportunity to re-examine its strategy for CAIR2 and is proposing a new approach to better serve the needs of Californians. Key objectives of the new strategy for CAIR include the following:  

1. The solution must be capable of managing a large volume of incoming submissions and responding to system queries from its approximately 10,000 submitting partners, which includes scalability and interoperability.  
2. An improved/optimized patient matching algorithm is needed to support accurate and rapid processing of a high volume of electronic data being submitted around the clock.   
3. Easily configurable parameters are needed to accommodate changing business rules such as changes needed to the vaccine recommendation evaluator.   
4. System and hosting stability are essential during high traffic periods such as during a pandemic.  
5. Better internal and external reporting functionality is needed to support all IIS users, including health care providers, health plans, and the CDC.  
6. Compliance with FHIR standards.