KEYWORDS:
Immunization, Vaccination coverage, National Immunization Survey (NIS)
BACKGROUND:
The NIS is an ongoing, nationwide, random-digit-dial survey used to assess vaccination coverage among 19-35 month old children in the U.S. Currently, only provider-reported data are used to monitor vaccination coverage in the NIS. Approximately 15% of sampled children do not have parental consent to contact providers and an additional 15% have missing vaccination data from providers. To improve accuracy of the coverage estimates, alternative sources of immunization histories are needed to supplement missing information.
OBJECTIVE:
To supplement missing provider data in the NIS, we examine registries as possible sources of immunization histories. Catchment areas with well-established registry databases were selected to: 1) test whether parental consent to contact registry offices can be obtained, 2) evaluate coverage of the NIS children in the registry database, and 3) evaluate the quality of the immunization information obtained from the registries.
METHOD:
NIS-household respondents in four registry catchment areas were asked to give consent to contact immunization providers and registries to obtain immunization records. Immunization histories of consented children were obtained via mail-questionnaires. The completeness and accuracy of registry- and provider-reported data are compared.
RESULT:
For the four areas, the consent rate to contact registries (85%) was similar to those for providers (87%). Among 556 children with consent to contact registries, 77% (range: 58-84%) had at least one vaccination entry in the registry database whereas 74% (n=569)had data from the providers. Vaccine-specific coverage rates from registry data were consistently lower than provider-based rates. For the four catchment areas, the registry-based 4:3:1:3 coverage rates ranged from 45-68%, and for the providers 65-81%.
CONCLUSION:
Preliminary findings support the feasibility of supplementing missing provider data with registry data. Respondents who consented to contact providers also tended to give consent to contact registries. Although a higher proportion of children were identified in the registries, vaccination histories appeared to be incomplete. Until data quality of registry database improves, the NIS will continue to rely solely on provider-reported data to monitor vaccination coverage.
LEARNING OBJECTIVES:
Evaluate quality of the data obtained from the immunization registries to supplement missing immunization histories in the NIS.
Web Page: www.cdc.gov/nis
Handout (.ppt format, 297.0 kb)
Back to Surveys, Charts, and Registries: Combining Date Sources to Produce More Reliable Vaccination Coverage Estimates
Back to The 2003 Immunization Registry Conference (October 27-29, 2003)