Validation of an Immunization Information System Against the National Immunization Survey and Improvement of Hepatitis B Birth Dose Coverage in New York City

Learning Objectives for this Presentation:
By the end of the presentation participants will be able to describe a method for and the importance of, validating data in an Immunization Information System (IIS).

Background:
Currently, immunization coverage at the state and local level is measured by the National Immunization Survey (NIS). Limitations of the NIS are that it reflects 2 year old data and local estimates have wide confidence intervals, limiting its usefulness for assessing programmatic interventions to improve coverage. High quality IISs can overcome the NIS's methodological limitations and provide more timely data for program support.

Objectives:
To validate the Hepatitis B birth dose (HBBD) coverage data in New York City's (NYC) IIS by comparing it to NIS estimates, and to assess, through the IIS, the impact of outreach activities on HBBD coverage.

Methods:
IIS based HBBD coverage was calculated for the same birth cohorts as in the NIS samples of 2004, 2005 and 2006 and was compared to the corresponding NIS estimate. Outreach to birthing facilities provided facility specific HBBD coverage together with materials in support of universal HBBD policies. To measure the impact of the outreach, IIS based coverage rates were calculated for children born in 2006 and 2007 to-date, data not yet available in NIS.

Results:
HBBD coverage in the IIS matched, within the confidence intervals, NIS data for the last 3 years: 27.4% vs. 34.1%+7.4% in 2004; 29.9% vs. 31.5%+8.0% in 2005 and 32.7% vs. 38.7%+7.0% in 2006. IIS based coverage for children born in 2006 and 2007 to-date were 43.1% and 50.0%, respectively.

Conclusions:
Comparison with NIS shows that the IIS provides valid data on HBBD coverage. Validation of the IIS data has allowed us to monitor birth dose coverage in “real time” and to provide birthing hospitals with ongoing and timely feedback. Preliminary findings suggest substantial improvement in birth dose coverage.