Factors associated with adolescent HPV vaccination in the U.S.: A systematic review of reviews and multilevel framework to inform intervention development

Multilevel factors impact HPV vaccine series initiation and completion among adolescents in the U.S. Synthesis of these factors is needed to inform intervention development and to direct future research. Current frameworks synthesizing factors focus on females only and do not include both series initiation and completion outcomes. We conducted a systematic review of reviews to identify modifiable individual-, provider-, and clinic-level factors associated with HPV vaccination outcomes among U.S. adolescents and developed a multilevel framework illustrating relations between factors to inform intervention development. We searched Medline, PsychInfo, Pubmed, CINAHL, and ERIC databases and included reviews published 2006 to July 2, 2018 describing individual-, provider-, or clinic-level factors quantitatively associated with HPV vaccination among U.S. adolescents. Two coders independently screened reviews, extracted data, and determined quality ratings. Sixteen reviews containing 481 unique primary studies met criteria. Factors synthesized into the multilevel framework included parent psychosocial factors (knowledge, beliefs, outcome expectations, intentions) and behaviors, provider recommendation, and patient-targeted and provider-targeted clinic systems. The scope of our framework and review advances research in two key ways. First, the framework illustrates salient modifiable factors at multiple levels on which to intervene to increase HPV vaccination. Second, the review identified critical gaps in the literature at each level. Future research should link the body of literature on parental intentions to vaccination outcomes, identify provider psychosocial factors associated with recommendation behaviors and subsequent vaccine uptake in their patient population, and understand clinic factors associated with successful implementation of patient- and provider-targeted system-level interventions.