Correlates for Second-dose Varicella Vaccination in School-age Children in a Managed Care Organization in California

Abstract

To identify correlates of nonadherence to the recommendation for routine second-dose varicella vaccination in a diverse sample of school-age children. A total of 67,977 children of 4-6 years (51% male, 50% Hispanic) were included in this retrospective cohort study. The second-dose varicella vaccination history was evaluated by using the Kaiser Immunization Tracking System. Correlation and multivariable regression analyses were used to test the association between potential correlates and nonadherence to the second-dose varicella vaccination. Four-year-old children had a significantly higher vaccination rate (76.1%) than 5-year-olds (43.2%) and 6-year-olds (17.3%) by 12 months after the implementation of routine second-dose varicella vaccination. Non-Hispanic white race [rate ratio (RR): 1.13 (95% CI: 1.11-1.15)], living in an area of >75% adults with a high-school diploma [RR: 1.17 (95% CI: 1.14-1.20)], and having a primary care provider specializing in family medicine [RR: 1.15 (95% CI: 1.11-1.18)] significantly correlated with nonadherence. Missed opportunity was found in 59.7% (n=20,465) of children who did not receive the second-dose varicella vaccine in spite of at least 1 outpatient visit and in 15.8% (n=5407) who received some other vaccines during the follow-up period. Efforts targeting non-Hispanic white and black children, parents with a high education level and family medicine physicians might improve uptake of the routine 2-dose varicella vaccination. Incorporation of a requirement for the second-dose varicella vaccine into the school law might help achieve high adherence to the routine 2-dose varicella vaccination in school-age children.