RESEARCH ARTICLE Public Health Impact of Complete and Incomplete Rotavirus Vaccination among Commercially and Medicaid Insured Children in the United States

Background This study (NCT01682005) aims to assess clinical and cost impacts of complete and incom-plete rotavirus (RV) vaccination. Methods Beneficiaries who continuously received medical and pharmacy benefits since birth were identified separately in Truven Commercial Claims and Encounters (2000–2011) and Tru-ven Medicaid Claims (2002–2010) and observed until the first of end of insurance eligibility or five years. Infants with1 RV vaccine within the vaccination window (6 weeks-8 months) were divided into completely and incompletely vaccinated cohorts. Historically unvacci-nated (before 2007) and contemporarily unvaccinated (2007 and after) cohorts included children without RV vaccine. Claims with International Classification of Disease 9th edition (ICD-9) codes for diarrhea and RV were identified. First RV episode incidence, RV-related and diarrhea-related healthcare resource utilization after 8 months old were calculated and compared across groups. Poisson regressions were used to generate incidence rates with 95 % confidence intervals (CIs). Mean total, inpatient, outpatient and emergency room costs for first RV and diarrhea episodes were calculated; bootstrapping was used to construct 95 % CIs to evaluate cost differences. Results 1,069,485 Commercial and 515,557 Medicaid patients met inclusion criteria. Among com-mercially insured, RV incidence per 10,000 person-years was 3.3 (95 % CI 2.8–3.9) for completely, 4.0 (95 % CI 3.3–5.0) for incompletely vaccinated, and 20.9 (95 % CI 19.5–22.4) for contemporarily and 40.3 (95 % CI 38.6–42.1) for historically unvaccinated. Rates i