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 incomplete 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 Truven Medicaid Claims (2002-2010) and observed until the first of end of insurance eligibility or five years. Infants with ≥1 RV vaccine within the vaccination window (6 weeks-8 months) were divided into completely and incompletely vaccinated cohorts. Historically unvaccinated (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 commercially 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 in Medicaid were 7.5 (95% CI 4.8-11.8) for completely, 9.0 (95% CI 6.5-12.3) for incompletely vaccinated, and 14.6 (95% CI 12.8-16.7) for contemporarily and 52.0 (95% CI 50.2-53.8) for historically unvaccinated. Mean cost for first RV episode per cohort member was $15.33 (95% CI $12.99-$18.03) and $4.26 ($95% CI $2.34-$6.35) lower for completely vaccinated versus contemporarily unvaccinated in Commercial and Medicaid, respectively.

CONCLUSIONS: RV vaccination results in significant reduction in RV infection. There is evidence of indirect benefit to unvaccinated individuals.