Evaluating Immunization Coverage in New York City by Geographic Area

Background: According to the 2008 National Immunization Survey (NIS), immunization coverage in New York City (NYC) for the 4:3:1:3:3:1 series is 75.4%, below the Healthy People 2010 goal of 80%. To better understand coverage in NYC, an analysis was performed using: the Citywide Immunization Registry (CIR), maintained by the NYC Department of Health and Mental Hygiene to record immunizations given to children <19 years and the Automate the Schools Database (ATS), maintained by the NYC Department of Education for school entry immunization requirements.

Objectives:

• To determine whether neighborhoods in NYC vary in immunization coverage.
• To identify and target providers in low coverage neighborhoods for outreach to raise overall coverage levels.

Methods: CIR and ATS coverage by zip code were mapped utilizing ArcGIS. As NIS data indicate that the 4^th DTP is the component of the 4:3:1:3:3:1 series that lowers overall immunization coverage, a retrospective analysis of DTP4 coverage of NYC children entering public school in 2007-08 was conducted using the ATS dataset. To identify areas with the highest number of children not up-to-date, coverage was weighted by number of children born in each zip code in 2008 using CIR birth record data.

Results: Mapping highlighted the difference in coverage between CIR and ATS datasets, with CIR having lower estimates, likely due to under-reporting. DTP4 coverage varied within the five NYC boroughs (50%-92.2%).  Ten zip codes with the largest number of under-immunized children were identified, five in Brooklyn, four in the Bronx, and one in Queens representing an estimated 15.4% of NYC's under-immunized children.

Conclusions: Efforts are underway to integrate immunization data in ATS and CIR. Mapping of several large data sets enabled us to identify areas and medical offices in NYC where either childhood immunization coverage or reporting were lowest. Strategies are being developed to promote best practices and increase coverage in these target locations.