179. Individual and State-level Factors Associated with Receipt of Multiple Recommended Adolescent Vaccines in the United States
Authors: La Elizabeth M , Garbinsky Diana , Hunter Shannon , Poston Sara , Novy Patricia , Ghaswalla Parinaz 
Published: January 2021

Abstract

Background
The Advisory Committee on Immunization Practices (ACIP) routinely recommends several adolescent vaccines, including human papillomavirus (HPV); quadrivalent meningococcal conjugate (MenACWY); and tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines. Limited data are available on the percentage of adolescents receiving this complement of ACIP-recommended vaccines and factors that may increase likelihood of completion.

Methods
This study used 2015–18 pooled National Immunization Survey-Teen (NIS-Teen) data to estimate national and state-level completion rates by age 17 of a two-dose MenACWY series, two- or three- dose HPV series (depending on age at first vaccination), and a Tdap vaccine, using multivariable logistic regression modeling to adjust for individual characteristics. NIS-Teen data were then combined with public state-level data to construct a multilevel model evaluating effects of both individual- and state-level factors on completion.

Results
After adjusting for individual-level factors, the national completion rate for these ACIP-recommended vaccines by age 17 was 30.6% (95% confidence interval [CI]: 30.1–31.0%). However, rates for individual states varied substantially, from 11.3% in Idaho (CI: 6.9–18.0%) to 56.4% in Rhode Island (CI: 49.8–62.8%) (Figure 1).
In the multilevel model, individual characteristics associated with increased likelihood of receiving the recommended vaccines by age 17 included female gender, black or Hispanic race, Medicaid coverage (vs. private/other), last provider visit at age 16 or 17, generally having ≥1 provider visit in last year, and receiving a provider recommendation for HPV vaccination. Residing in a state with a MenACWY vaccination mandate for elementary and secondary schools was the only state-level variable that significantly increased the likelihood of completion (odds ratio: 1.6; CI: 1.2–2.3) (Figure 2).
Figure 1: Model-Adjusted Completion Rates of ACIP-Recommended HPV, MenACWY, and Tdap Vaccines by Age 17 Years in the United States, 2015–18. ACIP, Advisory Committee on Immunization Practices; HPV, human papillomavirus; MenACWY, quadrivalent meningococcal conjugate; Tdap, tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis. Note: Vaccination completion is based on completion of the HPV series (i.e., receipt of 2 doses for individuals aged 9–14 years at first vaccination or receipt of 3 doses for individuals aged 15 years or older at first vaccination), completion of the MenACWY series (i.e., receipt of 2 doses), and receipt of a Tdap vaccine. Note: Model-adjusted composite vaccination completion is adjusted for sex, race/ethnicity, mother’s educational attainment, health insurance status, continuity of health insurance coverage since age 11, whether the individual was 16 or 17 years old at their last checkup, number of physician or other healthcare professional visits in past 12 months, whether a doctor or other healthcare professional ever recommended that the individual receive HPV vaccination, and state. The model-adjusted estimate is generated by taking the average of the predicted probability of vaccination for each individual as if they were all from the same state (while retaining all other characteristics).

Figure 2: Individual-Level and State-Level Characteristics Associated with an Individual’s Completion of ACIP-Recommended HPV, MenACWY, and Tdap Vaccines by Age 17 Years in the United States, 2015–18. ACIP, Advisory Committee on Immunization Practices; CI, confidence interval; HCP, healthcare professional; HPV, human papillomavirus; MenACWY, quadrivalent meningococcal conjugate; ref, referent category; Tdap, tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis. Note: Bold characters and darker circles indicate significant results. Note: Vaccination completion is based on completion of the HPV series (i.e., receipt of 2 doses for individuals aged 9–14 years at first vaccination or receipt of 3 doses for individuals aged 15 years or older at first vaccination), completion of the MenACWY series (i.e., receipt of 2 doses), and receipt of a Tdap vaccine.

Conclusion
Recommended adolescent vaccine completion rates are suboptimal and highly variable across states. Provider recommendations, visits at 16–17 years of age, and state mandates for MenACWY are implementable strategies associated with completion of recommended adolescent vaccines.

Funding
GlaxoSmithKline Biologicals SA (study identifier: HO-19-19991)

Disclosures
Elizabeth M. La, PhD, RTI Health Solutions (Employee) Diana Garbinsky, MS, GSK (Other Financial or Material Support, The study was conducted by RTI Health Solutions, which received consultancy fees from GSK. I am a salaried employee at RTI Health Solutions and received no direct compensation from GSK for the conduct of this study..) Shannon Hunter, MS, GSK (Other Financial or Material Support, Ms. Hunter is an employee of RTI Health Solutions, who received consultancy fees from GSK for conduct of the study. Ms. Hunter received no direct compensation from the Sponsor.) Sara Poston, PharmD, The GlaxoSmithKline group of companies (Employee, Shareholder) Patricia Novy, PhD, GSK (Employee, Shareholder) Parinaz Ghaswalla, PhD, ORCID: 0000-0002-2883-5590, GlaxoSmithKline (Employee, Shareholder)