Interim results: state-specific influenza A (H1N1) 2009 monovalent vaccination coverage - United States, October 2009-January 2010.

In July 2009, the Advisory Committee on Immunization Practices (ACIP) issued recommendations for the use of influenza A (H1N1) 2009 monovalent vaccine. Distribution of 2009 H1N1 vaccine in the United States began on October 5, using a system that allocated available vaccine to states proportional to their populations. By the end of 2009, approximately 61 million persons had been vaccinated. By January 29, 2010, approximately 124 million doses had been distributed. To provide preliminary state-specific estimates of 2009 H1N1 vaccination coverage as of the end of January, CDC analyzed results from the Behavioral Risk Factor Surveillance System (BRFSS) and the National 2009 H1N1 Flu Survey (NHFS), using data collected during November 2009--February 2010. This report summarizes the results of that analysis, which found that, by state, estimated 2009 H1N1 vaccination coverage as of the end of January among persons aged >/=6 months ranged from 12.9% to 38.8% (median: 23.9%). Median coverage was 36.8% for children aged 6 months--17 years, 20.1% for adults aged >/=18 years, and 33.2% for persons in the ACIP initial target group. The wide variation in 2009 H1N1 vaccination rates among states suggests opportunities for improvement in future seasons, such as maintaining and increasing the reach of networks of private providers as vaccinators and distributing more vaccine through public venues (e.g., schools).