Age at Human Papillomavirus Vaccine Initiation Among Adolescents and Young Adults From 22 Pediatric Practices in the Northeastern United States.

Purpose To examine trends in human papillomavirus (HPV) vaccine initiation and its determinants. Design This retrospective correlational study involved 12,260 individuals born between 1996 and 2000 receiving care from one of 22 pediatric practices in the northeastern region of the United States between 2016 and 2017. Methods We extracted data about HPV vaccination status and date, birth year, race, ethnicity, language, and geographic regions. Mean age at initiation was estimated using descriptive statistics. Multiple linear regression with weighted least squares was used to examine its correlates. Findings Of 12,260 individuals, about 76% initiated the HPV vaccination series at 9 to 17 years of age. While the initiation age decreased overall for both females and males (e.g., 14.3 vs. 16.2 years and 13.8 vs. 14.4 years in the 1996 vs. 2000 birth cohorts, respectively), a greater reduction was noted for males. Individuals tended to delay initiation if they were non-Hispanic or Asian and resided in urban areas. Conclusions Most adolescents in our sample started HPV vaccination later than the recommended age, with variations in different demographic groups. Rapid improvement in on-time HPV vaccination is occurring, especially for males. Clinical relevance The findings of this analysis emphasize continuous efforts to increase on-time HPV vaccination rates for all groups, including non-Hispanic whites and female adolescents, to eliminate current and possible disparities.