A stepped wedge trial of a healthcare provider–focused intervention to increase human papillomavirus (HPV) vaccine initiation among survivors of childhood cancer.
Authors: Landier Wendy , Campos González Paula D. , Richman Joshua S. , Chen Yanjun , Gilkey Melissa B. , Cherven Brooke , Aye Jamie , Castellino Sharon M. , Gramatges Maria Monica , Lindemulder Susan , Russell Thomas B. , Turcotte Lucie Marie , Keith K. Elizabeth , Salem Adelynn J. , Chollette Veronica , Mitchell Sandra A. , Colditz Graham A. , Bhatia Smita , Klosky James L. 
Published: June 2024

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Background: Childhood cancer survivors are at increased risk for human papillomavirus (HPV)-related cancers. HPV vaccination is highly protective against HPV acquisition. However, we have previously shown that initiation rates among survivors are low, primarily due to lack of healthcare provider recommendation for the vaccine. Methods: We conducted a stepped wedge trial from 2021 to 2023 to evaluate the effectiveness of an evidence-based healthcare provider-focused intervention (HPV PROTECT; NCT04469569) in increasing HPV vaccine initiation rates 1y following implementation. The intervention includes provider communication training to enhance vaccine recommendation skills, audit/feedback regarding clinic vaccination rates, and patient-directed resources in multiple languages tailored to pediatric oncology settings. We measured the effectiveness of the intervention in a racially, ethnically, and geographically diverse sample of HPV vaccine naïve childhood cancer survivors, aged 9-17y, and ≥1y post-completion of therapy returning to pediatric oncology clinics for follow-up care at 6 sites. The primary outcome of interest was HPV vaccine initiation rates (abstracted from state vaccine registries) at end of each study year. Baseline data were collected for all sites in Y1, three sites were randomly selected to receive the intervention in Y2, and the remaining three in Y3. The intervention effect was tested using a longitudinal logistic regression model for initiation with intervention as the main fixed effect, adjusting for survivor age, cancer diagnosis, time off-therapy, sex, race, ethnicity, and receipt of hematopoietic cell transplantation. The secular trend (estimated using pre-intervention data from Y1 and Y2) was included as an offset, and site was included as a random effect. The intervention effect was reported as odds ratio (OR) for initiation with 95% confidence intervals (CI). Results: A total of 1779 unique vaccine naïve survivors (47.1 % leukemia; 55.1% male; 51.5% non-Hispanic white) completed 2689 clinic visits across 6 sites. Median (range) age at diagnosis was 5.1y (0-16.5), at study entry was 12.3y (9-17.9), and median time off-therapy was 5.5y (1.0-17.3). Overall incident HPV vaccine initiation was 16.0% at baseline. The adjusted odds of vaccine initiation were 1.3-fold (95%CI, 1.03-1.6; p = 0.03) higher post-intervention vs. pre-intervention, accounting for secular trend OR of 1.1. Overall prevalence of vaccine initiation increased from 51.9% pre-intervention to 61.3% post-intervention. Conclusions: The improvement in childhood cancer survivor HPV vaccine initiation rates in a diverse sample following implementation of a healthcare provider-focused intervention underscores the potential for pediatric oncology providers to positively impact HPV vaccine uptake in this vulnerable population. Clinical trial information: NCT04469569 .