Trends in compliance with two-dose influenza vaccine recommendations among children aged 6 months through 8 years.

Children aged <9 years may require two doses of influenza vaccine to achieve an adequate immune response to protect against the disease. We analyzed data for >2 million children in each influenza season from 2007 to 2012 from eight Immunization Information System Sentinel Sites to assess trends in two-dose compliance. Compliance was calculated by influenza season, age group, and influenza vaccination history. Two-dose compliance increased from 49% to 60% among 6-23 month olds from 2007 to 2012; no increase was observed for 2-4 or 5-8 year olds. In each season, compliance was 3-12 times higher among 6-23 month olds compared to older children and was two times higher among influenza vaccine naïve children compared to previously vaccinated children. Improved messaging for providers and parents about the importance of the two-dose recommendation, about which children are eligible for two doses, and provider access to complete influenza vaccination histories for all children are needed.