KEYWORDS:
CASA, AFIX, immunization registry

BACKGROUND:
Chart audits are the gold standard for assessing practice coverage but are time and labor intensive. Immunization registries offer the potential for reliable and timely assessments.

OBJECTIVE(S):
To compare practice immunization coverage assessed through chart audits and a private immunization registry.

METHOD(S):
At 5 practices serving a low-income, minority community in New York City, we reviewed the medical charts and immunization registry records for a sample of randomly selected children ages 6-23 months (n=3,343, 1,050 6-11 months, 1,846 12-23 months). We assessed age-appropriate immunization rates for DTaP, Polio, MMR, and Hib (4:3:1:3), using both chart and registry data at 4, 10, and 16 months after registry launch (April, October 2000 and April 2001).

RESULT(S):
Virtually all children (99.7%) in the chart audit sample had records in the registry. The difference between CASA and registry coverage for children <12 months decreased from 20% at 4 months after registry launch to 1% at 16 months after launch. For 12-23 month-olds the difference decreased from 45% to 11% in the same time period. Compared to the chart audits, at the last assessment date the sensitivity and specificity of the registry was 99% and 98% for children <12 months and 76% and 82% for children 12-23 months.

CONCLUSIONS(S):
As early as 16 months after launch, a private immunization registry developed reliable assessments of practice immunization coverage for children <12 months. For 12-23 month-olds, a longer period of regular use, probably 2 years, may be needed to obtain reliability within 5%.

LEARNING OBJECTIVES:
Present a new use of a private immunization registry.