Promoting HPV Vaccination in Safety-Net Clinics: A Randomized Trial

Abstract

Objectives: Evaluate effects of a multicomponent intervention (human papillomavirus [HPV] vaccine-specific brochure and recalls) on HPV vaccination and secondarily examine if race/ethnicity moderates effects.

Methods: Unvaccinated girls aged 11 to 18 years attending 4 safety-net pediatric clinics and their parent/guardian (n = 814 dyads) were randomized to (1) active comparison (general adolescent vaccine brochure), or (2) intervention consisting of a HPV vaccine-specific brochure, telephone recalls to parents who declined, and recalls to patients overdue for doses 2 and 3. HPV 1-dose and 3-dose coverages were assessed via electronic health records 12 months after randomization. Multivariate logistic regressions estimated adjusted odds and marginal predicted vaccine coverage by study arm and race/ethnicity.

Results: Intent-to-treat analyses found no main effect of the HPV vaccine-specific brochure on 1-dose coverage (42.0% vs 40.6%); however, secondary analyses found race/ethnicity was a significant moderator such that the intervention was effective only for Hispanic individuals (adjusted odds ratio [AOR] 1.43; 95% confidence interval [CI] 1.02-2.02), and not effective for black individuals (AOR 0.64; 95% CI 0.41-1.13). Recalls to parents who declined the vaccine during the index visit were not effective, but recalls to patients overdue for doses 2 and 3 were effective at increasing 3-dose coverage regardless of race/ethnicity (AOR 1.99; 95% CI 1.16-3.45).

Conclusions: Educational materials describing only the HPV vaccine were effective for Hispanic but not black individuals. Future research should test mechanisms that may mediate intervention effects for different racial/ethnic groups, such as different informational needs or vaccine schemas (experiences, beliefs, norms).

Trial registration: ClinicalTrials.gov NCT01729429.

FIGURE 1

Enrollment and randomization of eligible adolescent female patients and their parent/guardian (dyad) and construction of analytic samples for study hypotheses. Dyads were randomized when upcoming appointments were identified via EHR. Recalls were delivered via telephone.

FIGURE 2

Model-adjusted marginal predicted HPV vaccine 1-dose coverage estimates and 95% CI 12 months after randomization among adolescent female patients attending 4 safety-net clinics. Estimates controlled for all variables in Table 2’s interaction model. Act Comp, active comparison Group; INT, intervention group.