Learning Objectives for this Presentation:
By the end of this presentation participants will be able to describe the impact that a vaccination program can have in reducing Hepatitis A infection rates.

Background:
In July 2005, New York City (NYC) Department of Health and Mental Hygiene's (DOHMH) surveillance system was enhanced allowing for better case ascertainment, more timely case follow-up, and the identification and targeting of neighborhoods with high infection rates for Hepatitis A. In October 2005, ACIP recommended universal vaccination of all 12-23 month olds and catch up for older children.

Objectives:
To assess the impact of introducing universal Hepatitis A vaccination on disease rates in NYC.

Methods:
In December 2005, all providers in NYC were notified of the universal Hepatitis A vaccine recommendation through the Citywide Immunization Registry (CIR). In May 2006, based on surveillance data, DOHMH outreached to all providers and to parents in neighborhoods with Hepatitis A infection rates > 5/100,000, recommending catch-up for children through age 5. The CIR was used to estimate adherence to the Hepatitis A vaccination recommendations. Surveillance data were used to compare the infection rates in NYC before and after the vaccination campaign.

Results:
By October, 26,122 children 12-23 months old received at least one dose of Hepatitis A vaccine, indicating that a minimum of 24% of this age cohort were vaccinated according to CIR data; 43,581 children 24-59 months of age received at least 1 dose of Hepatitis A vaccine. Preliminary surveillance data from July-September 2006 indicated a reduction in infection rates compared to the same time period in 2005.

Conclusions:
Successful implementation of Hepatitis A vaccination may have been associated with an reduction in rates of disease. The long-term impact will be determined by ongoing surveillance.