KEYWORDS:
Quality Control, Vaccination Histories, Shot Card Records

BACKGROUND:
The National Immunization Survey (NIS) measures vaccination coverage rates among children aged 19-35 months in the U.S., the 50 states, the District of Columbia and 27 large urban areas.

OBJECTIVE(S):
To present results of ongoing quality control procedures used to ensure the validity and accuracy of the vaccination coverage rates.

METHOD(S):
The NIS consists of a random-digit-dialing telephone survey of the parents/guardians, followed by a mail survey of the children's providers. Currently, provider reported histories are used to produce the vaccination coverage rates. The NIS data are evaluated for reporting errors in the date of birth and vaccination dates. Immunization histories reported by households and providers are compared. To enhance the quality of the coverage estimates, new methods are being evaluated to supplement missing provider information with household-reported histories.

RESULT(S):
Approximately 48% of the household respondents provided vaccination histories from a written shot card record in the 2000 NIS. Among 11,963 children with household shot card- and provider-reported histories, the up-to-date status for the vaccine series 4:3:1:3 matched for 88% of the children. A comparison of 4:3:1:3 coverage estimates from the household and provider reports showed approximately 19% underreporting from the shot card records and 53% from memory recall.

CONCLUSIONS(S):
NIS is the only source of comparable vaccination coverage rates of high quality across states and urban areas in the U.S. The underreporting in household reports strongly supports the use of provider data. High agreement in the up-to-date status supports the future research on
supplementing missing provider data with the household shot card histories.

LEARNING OBJECTIVES:
To demonstrate the importance of collecting provider-reported vaccination histories, show that provider reports may contain erroneous or incomplete information, and to indicate that procedures can be used to improve completeness of the provider reports.