Trends in U.S. pediatric influenza vaccination from 2006 to 2010 among children with private insurance

In the United States, recommendations for the annual influenza vaccination of children have expanded significantly in recent years. Additionally, to facilitate influenza vaccination delivery by providers, recent recommendations have encouraged vaccination as soon as vaccine is available and throughout the influenza season. However, until now, there have been limited data published describing pediatric providers' responses to these recent recommendations. De-identified, patient-level data from an electronic health care reimbursement claims database that contains more than 60% of all medical claims from outpatient settings in the US were analyzed. Only claims from privately insured children were available; administration of federally purchased vaccine (i.e., via the Vaccines for Children program) and vaccinations administered in settings where claims data are not generated were not captured. Weekly counts of influenza vaccinations administered to children 6 months through 18 years of age between August 1 and March 31 for the 2006-2007 through 2009-2010 seasons were projected to yield national estimates. Seasonal vaccination peaked in November for the 2006-2007 and 2007-2008 seasons, October for the 2008-2009 season, and September for the 2009-2010 season. The proportion of vaccinations administered before November 1 increased each season from 2006-2007 through 2009-2010. In all seasons, vaccination dramatically declined in December and continued at a steadily declining rate through the end of the season. Vaccine delivery to children 6-23 months of age was more dispersed over the vaccination season relative to older age groups. Among children 6-23 months and 2-18 years of age, use of preservative-free inactivated vaccine and live attenuated vaccine, respectively, increased significantly over the study period. While pediatric influenza vaccination occurred earlier each year, vaccination in later months has not increased in recent seasons, despite efforts to extend the vaccination season.