Patterns of rotavirus vaccine uptake, use, and effectiveness in privately-insured US children, 2006-2010

Objectives. Our study examines predictors and timeliness of rotavirus vaccine administration among privately-insured US infants and children from 2006 to 2010. We also calculate direct, indirect, total, and overall rotavirus vaccine effectiveness estimates as well as the number of rotavirus and acute gastroenteritis hospitalizations prevented among infants and children aged 8 to 20 months. Methods. Bivariate analyses and multivariable log-risk models were used to determine predictors of rotavirus vaccine series initiation and completion among infants in the MarketScan Research Databases. Vaccine effectiveness estimates were derived using Cox proportional hazards regression, stratifying by calendar year and adjusting for month of birth. Incidence rate differences were calculated to determine the absolute number of rotavirus and acute gastroenteritis hospitalizations prevented in the cohort. Results. Most infants received the rotavirus vaccines at the recommended ages, but more infants completed the series for monovalent rotavirus vaccine than pentavalent rotavirus vaccine or a mix of the two vaccines (87% versus 79% versus 73%). In multivariable analyses, the strongest predictors of rotavirus vaccine series initiation and completion were receipt of the diphtheria, tetanus and acellular pertussis vaccine (Initiation: RR=7.50, 95% CI=7.30-7.71; Completion: RR=1.26, 95% CI=1.23-1.29), visiting a pediatrician versus family physician (Initiation: RR=1.51, 95% CI=1.49-1.52; Completion: RR=1.13, 95% CI=1.11-1.14), and living in a large metropolitan versus smaller metropolitan, urban, or rural area. Direct vaccine effectiveness of one or more doses of any rotavirus vaccine in preventing rotavirus gastroenteritis hospitalizations in children 8 to 20 months ranged from 87 to 92% for each calendar year, 2007-2010. Accounting for indirect protection increased the total vaccine effectiveness by an additional 3 to 8%. Failing to account for indirect protection underestimated the absolute number of rotavirus gastroenteritis hospitalizations prevented in rotavirus-vaccinated children by 1.5 to 5.3-fold. Conclusions. Accounting for only the direct effectiveness of the rotavirus vaccine severely underestimated the total number of rotavirus gastroenteritis hospitalizations prevented by the US rotavirus vaccine program. Interventions to further increase rotavirus vaccine coverage should consider targeting family physicians and encouraging completion of the vaccine series.Doctor of Philosoph