Mixing of diphtheria, tetanus, and acellular pertussis (DTaP) vaccines in a population of children in managed care

Abstract

The Advisory Committee on Immunization Practices recommends administering diphtheria, tetanus and acellular pertussis (DTaP) vaccines to children at 2, 4, 6, 15–18 months, and 4–6 y of age; preferably with the same-brand vaccine for the whole series. We estimated age-appropriate DTaP dose completion and the proportion of children receiving a “mixed” DTaP vaccination series (ie, including DTaP vaccines from ≥2 brands) across the 3 milestones. Commercially-insured children born between 01/01/2003 and 04/30/2011 were identified from United States health insurance claims data and assigned to ≥1 of 3 study cohorts based on the duration of continuous health plan enrollment: 1) birth to <8 months; 2) birth to <20 months; 3) birth to <7 years. Dose completion and brand mixing of the first 3, first 4 or all 5 doses were measured in the respective cohorts. Administered DTaP vaccinations were identified in claims data and classified by brand (based on vaccine components and manufacturer). The analysis included children who received ≥2 DTaP vaccinations and had known brand information for all doses. Age-appropriate dose completion was 77% with 3 doses (<8 months cohort), 71% with 4 doses (<20 months cohort), and 85% with 5 doses (<7 years cohort). Mixed DTaP series were received by 4.7% (95% confidence interval [CI]: 4.6%-4.7%) in the <8 months cohort, 29.0% (95% CI: 28.6%–29.4%) in the <20 months cohort, and 39.0% (95% CI: 34.5, 43.6) in the <7 years cohort. DTaP mixing was just 4.7% for the first 3 doses but subsequently increased with the number of administered doses.

Keywords:

• children
• DTaP
• immunization schedule
• managed care programs
• vaccination

Abbreviations:

• ACIP
• Advisory Committee on Immunization Practices; CI
• confidence intervals; DTaP
• diphtheria
• tetanus and acellular pertussis vaccine; FDA
• Food and Drug Administration; NCQA
• National Committee for Quality Assurance; NDC
• National Drug Code; NIS
• National Immunization Survey; ORD
• Optum Research Database; US
• United States

Disclosure of Potential Conflicts of Interest

Ami Buikema and Fang Liu are employees of Optum, which was contracted by GlaxoSmithKline to conduct the study. Shanthy Krishnarajah is an employee of and owner of stock in GlaxoSmithKline. Cristina Masseria was an employee of GlaxoSmithKline at the time of the study and is currently a Pfizer employee.

Acknowledgments

Dawn Nicewarner, PhD and Elizabeth J. Davis, PhD (both of Optum) as well as Julia Donnelly (freelance publication manager, United Kingdom, on behalf of GSK Vaccines) provided editorial assistance. Stephanie Nelson and Margaret Burgess of Optum programmed the analytic dataset.

Authors' Contributions

Cristina Masseria conceived the study and its general design, assisted with interpretation of results and critically reviewed the manuscript. Ami Buikema developed the study design, assisted with the statistical analyses with respect to hypothesis testing, interpreted the results, and helped to draft the manuscript. Fang Liu performed the statistical analyses with respect to hypothesis testing, assisted with interpretation of results, and critically reviewed the manuscript. Shanthy Krishnarajah participated in critical decisions regarding the study's design, assisted with interpretation of results and critically reviewed the manuscript. All authors have read and approved the final manuscript.

Supplemental Material

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