Reduction in gastroenteritis in United States children and correlation with early rotavirus vaccine uptake from national medical claims databases.

BACKGROUND: We sought to estimate rotavirus disease reduction among children in hospital and office settings in the 4 US regions following rotavirus vaccine introduction and to estimate vaccine uptake.
METHODS: Two national third-party payer medical claims databases were used to examine the number of visits for gastroenteritis per annual nongastroenteritis visits among children aged <5 years during July 2003 to June 2008 in hospital and office settings. The gastroenteritis burden attributable to rotavirus was computed as the excess of all gastroenteritis visits during rotavirus seasons above the baseline of visits during nonrotavirus periods. Rotavirus vaccine uptake was estimated by comparing claims for rotavirus vaccine with those for diphtheria-tetanus-acellular pertussis vaccines.
RESULTS: In the South, Northeast, and Midwest, the typical winter-spring gastroenteritis peak due to rotavirus was markedly dampened in 2007-2008. Compared with the mean for 3 prevaccine seasons, the excess gastroenteritis visits that occurred during the 2007-2008 rotavirus season was reduced by >90% among infants in all care settings in 3 regions and by >70% among children aged 1 to 4 years. In the West, disease reductions were lower (53%-63% reduction among hospitalized infants). At the onset of the 2007-2008 season, coverage with > or =1 rotavirus vaccine dose was an estimated 57% among infants, 17% among children aged 1 year, and 0 among those aged 2 to 4 years.
CONCLUSIONS: The rotavirus burden in 2007-2008 was markedly reduced in all US regions and exceeded that explained by only direct protection of the youngest vaccinated children.