In 2009, a monovalent H1N1 influenza (H1N1) vaccine was manufactured in response to the pandemic of 2009 influenza A (H1N1) virus infection that emerged earlier in the year. The overall allocation of the H1N1 vaccine to the states was the purview of the federal government; thereafter, the states were accountable for distributing and reporting the number of doses of H1N1 vaccine administered weekly. This report describes how the Wisconsin Immunization Registry (WIR) was updated and used during the H1N1 immunization campaign and its role in meeting the federal H1N1 immunization reporting requirements. Activities to enhance the registry's functionality included the creation of a rapid data entry screen for providers to facilitate the entry of data into the WIR, and enhancing the reporting capabilities of the WIR to generate H1N1-related reports at the local level. Results of these activities included an increase in the number of WIR users, higher reported numbers of seasonal influenza doses administered, and the establishment of data streams from new users. Data completeness, the ability to accurately forecast doses needed, and validating administered doses were challenges in the changing environment.

(Disaster Med Public Health Preparedness. 2012;6:402-407)