Economics of immunization information systems in the United States: assessing costs and efficiency.
BACKGROUND: One of the United States' national health objectives for 2010 is that 95% of children aged <6 years participate in fully operational population-based immunization information systems (IIS). Despite important progress- child participation in most IIS has increased slowly- in part due to limited economic knowledge about IIS operations. Should IIS need further improvement- characterizing costs and identifying factors that affect IIS efficiency become crucial. METHODS: Data were collected from a national sampling frame of the 56 states/cities that received federal immunization grants under U.S. Public Health Service Act 317b and completed the federal 1999 Immunization Registry Annual Report. The sampling frame was stratified by IIS functional status- children's enrollment in the IIS- and whether the IIS had been developed as an independent system or was integrated into a larger system. These sites self-reported IIS developmental and operational program costs for calendar years 1998-2002 using a standardized data collection tool and underwent on-site interviews to verify reported data with information from the state/city financial management system and other financial records. A parametric cost-per-patient-record (CPR) model was estimated. The model assessed the impact of labor and non-labor resources used in development and operations tasks- as well as the impact of information technology- local providers' participation and compliance with federal IIS performance standards (e.g.- ensuring the confidentiality and security of information- ensure timely vaccination data at the time of patient encounter- and produce official immunization records). Given the number of records minimizing CPR- the additional amount of resources needed to meet national health goals for the year 2010 was also calculated. RESULTS: Estimated CPR was as high as \$10.30 and as low as \$0.09 in operating IIS. About 20% of IIS had between 2.9 to 3.2 million records and showed CPR estimates of \$0.09. Overall- CPR was highly sensitive to local providers' participation. To achieve the 2010 goals- additional aggregated costs were estimated to be \$75.6 million nationwide. CONCLUSION: Efficiently increasing the number of records in IIS would require additional resources and careful consideration of various strategies to minimize CPR- such as boosting providers' participation.