Age-appropriate compliance and completion of up to five doses of pertussis vaccine in US children

Abstract

Background: In the United States (US), diphtheria, tetanus, and acellular pertussis (DTaP) vaccination is recommended at 2, 4, and 6 months (doses 1-3), 15-18 months (dose 4), and 4-6 years (dose 5). The objective of this study (GSK study identifier: HO-14-14383) was to examine DTaP completion and compliance rates among commercially insured and Medicaid-enrolled children. Secondarily, the study aimed at identifying predictors of compliance/completion. Methods: Truven Health MarketScan Commercial and Multi-State Medicaid databases (2005-2013) were analyzed separately. Children born during 2005-2011 with ≥ 2 years continuous enrollment from birth provided data for doses 1-4; those with continuous enrollment from birth to their seventh birthday provided dose 5 data. Series compliance (each recommended dose by 3, 5, and 7 months; 19 months; seventh birthday) and completion (3 doses by 8 months; 4 by 24 months; 5 by seventh birthday) were calculated. Predictors of compliance/completion were identified using multivariable logistic regression. Results: A total of 367,493 commercially insured and 766,153 Medicaid-enrolled children were followed for ≥ 2 years; and 23,574 and 41,284, respectively, for ≥ 7 years. Series compliance to doses 1-3, 1-4, and 1-5 were 67.2%, 55.3%, 47.5% (commercial) and 37.4%, 27.3%, 14.4% (Medicaid), respectively. Predictors of better compliance/completion included: later birth year (commercial/Medicaid) and higher household income (commercial); predictors of worse compliance/completion included: Northeast residence (commercial), birth hospitalization ≥ 14 days (commercial/Medicaid), and Black race/ethnicity (Medicaid). Conclusions: DTaP series compliance/completion improved over time, but appear to be suboptimal. As this could increase pertussis risk, greater awareness of the importance of timely vaccination completion is needed. GSK study identifier: HO-14-14383.

Keywords: DTaP; Medicaid; Pertussis; United States; children; compliance; vaccination.

Figure 1.

DTaP series completion, dose compliance, and series compliance rates among commercially insured and Medicaid-enrolled children. DTaP diphtheria, tetanus, and acellular pertussis vaccine *Third and fourth doses were measured among those in the 2-year follow-up cohorts (commercial, n = 367,493; Medicaid, n = 766,153); fifth dose among those in the 7-year follow-up cohorts (commercial, n = 23,574; Medicaid, n = 41,284)\

Figure 2.

DTaP diphtheria, tetanus, and acellular pertussis vaccine(DTaP) third and fourth dose receipt status by the end of follow-up. DTaP diphtheria, tetanus, and acellular pertussis vaccine Sum of percentages may not equal 100.0% due to rounding *For children with ≥ 2 years of follow-up †Please see Table 1 for compliance timeframes

Figure 3.

Predictors of DTaP series compliance for doses 1–4 among commercially insured (A) and Medicaid-enrolled (B) children.CI confidence interval, DTaP diphtheria, tetanus, and acellular pertussis vaccine, LOS length of stay, NICU neonatal intensive care unit, OR odds ratio Bars show 95% CIs *ORs were adjusted for birth year, gender, geographic region, household income, NICU hospital stay, and birth hospitalization LOS †ORs were adjusted for birth year, gender, race/ethnicity, NICU hospital stay, birth hospitalization LOS, and basis of Medicaid eligibility