After implementation in September 2010 of required influenza vaccination for children in licensed child care programs, vaccination coverage among children aged 6-59 months in Connecticut increased from 67.8% during the 2009-10 influenza season to 84.1% in 2012-13, and the influenza-associated hospitalization rate in 2012-13 among children aged [less than or equal to] 4 years, compared with the 2007-08 season, decreased by 12%, the largest percentage decrease among the 11 Emerging Infections Program sites. In addition, the ratio of the influenza hospitalization rate among children aged [less than or equal to] 4 years to the overall (i.e., all ages) influenza hospitalization rate was lower in Connecticut (0.53) than in any of the other 10 sites. (author abstract)