Discussion

1. 2010 Birth Cohort (WA IIS) N = 87,301 No Rotavirus Dose n=16,951 (19.4) Rotavirus Dose n=70,350 (80.6) Full Coverage n=52,468 (60.1) Partial Coverage n=17,882 (20.5) No RV5 n=6,678 (7.6) No Vaccine n=10,273 (11.8) Background Results Conclusions • National Immunization Survey (NIS) 2009 and 2010 estimates ranked WA State among lowest in nation for rotavirus coverage (20.9% and 50.4%, respectively) • Prior to rotavirus vaccine introduction, one in 60 U.S. children were hospitalized for rotavirus by age 5 • Vaccines For Children Program (VFC) provides free vaccine to all children ≤ 18 years in WA State and distributes the RotaTeq (RV5) rotavirus vaccine • Recommended schedule for RV51 • WA State Immunization Information System (IIS) is a secure web-based registry with 95% participation among vaccine providers, covering 98% of VFC doses • Studies have found partial RV5 vaccination confers up to 85% protection (range: 69% - 85%)2,3 • 2 Boom, et al. Effectiveness of Pentavalent Rotavirus Vaccine in a Large Urban Population in the United States, Pediatrics 2010. 3 Staat, et al. Effectiveness of Pentavalent Rotavirus Vaccine Against Severe Disease, Pediatrics 2011. • To estimate rotavirus vaccine coverage in WA State using IIS data, and to explore maternal characteristics associated with partial or no rotavirus coverage • Rotavirus Vaccine Coverage Estimates • IIS data extracted for all children born during 2010 (n=97,664) • Records with no immunization data excluded (5,000) • Inactive records excluded (5,202) • Coverage groups assigned: • Maternal Predictors For ‘Partial’ or ‘No’ Coverage • IIS records linked to 2010 birth certificate data • ‘No vaccine’ group excluded from analyses • Dataset restricted to records with WA birth residence and complete data among variables of interest • X2 tests assessed univariate associations (Table 1) • Odds ratios generated from multivariate model (Table 2) • Analyses completed using SAS 9.3 and LinkPlus • Discussion • Rotavirus vaccine coverage estimates for WA using IIS data higher than NIS coverage estimates • Partial coverage known to confer substantial immunity, suggesting that 80.6% of 2010 birth cohort achieved some immunity despite only 60% achieving ‘full’ coverage • Among those with no RV5 dose, nearly 40% received another vaccine between 6 - 15 weeks of age; unclear whether vaccine was not offered or refused • Rotavirus unique vaccine in that first dose must be administered by 15 weeks of age, otherwise series not initiated • Coverage estimates highly variable among WA counties • The following maternal characteristics strongly associated with 'partial' coverage: younger age; AI/AN, Black, or Pacific Islander race; multiparity; ≤ high school education or some college (compared to ≥ college degree); Medicaid use • The following maternal characteristics strongly associated with ‘No RV5’: AI/AN race; married; multiparity; some college • Consistent with previously described risk factors for delayed or no vaccine coverage, multiparity significantly associated with 'partial' and 'no RV5' groups; odds increase with each previous live birth • Further studies needed to better understand reasons for no rotavirus vaccine coverage • < 100% of WA vaccine providers participate in the WA IIS • Since IIS initially populated with birth certificate data, unclear whether those with no immunization data refused all vaccines, see a provider who does not participate in IIS, or left the state • Inactive records lack ‘date effective’ for inactivity, therefore unclear whether these patients were active through rotavirus vaccine time period so they were excluded • Phyllis Reed1, Belinda Baker1, Janna Bardi1, Sherry Riddick2,Yousif Hozail2, Wayne Turnberg1, Natasha Close1, Kathryn MacDonald1, Tracy Sandifer1, Erica Smith3 • 1 Washington State Department of Health • 2 Washington State Immunization Information System • 3 Pennsylvania Department of Health Rotavirus vaccine coverage estimates using IIS data Multivariate Results = outcomes of interest = reference group Univariate Comparisons Objective Limitations Methods * Odds for partial coverage and no RV5 increased by 20% with each previous birth / older sibling Rotavirus vaccine coverage among 2010 birth cohort by county, WA State Acknowledgements * P-value < 0.05 when compared to ‘full’ coverage group + Continuous variable – mean expressed