Younger age at initiation of the human papillomavirus (HPV) vaccination series is associated with higher rates of on-time completion.

Vaccination rates for human papillomavirus (HPV) have remained disappointingly low. It is critical to identify methods to increase on-time vaccine series completion rates (before 13 or 15years). To determine whether younger age (9 to 10years of age) at HPV vaccine series initiation was associated with improved on-time completion rates compared to initiation at 11 to 12years, we examined the prevalence of on-time HPV vaccine series completion rates from August 2006 through December 2012 in a large, population-based cohort of children and adolescents (aged 9.5 to 27years) residing in Olmsted County, MN on December 31, 2012 (n=36,223). We compared age at vaccine initiation between individuals who successfully completed both 2 and 3 doses of the vaccination series on-time (before age 13.5 or 15.0years) using multivariate logistic regression. On-time completion of both 2 and 3 doses of the vaccine series by age 13.5 or 15.0years was significantly associated with initiation at 9 to 10years as compared to 11 to 12years after adjusting for sex, race, insurance status, frequent health care visits, and year of first vaccination (all p<.01). Interventions focused on beginning the vaccination series at 9 to 10years of age may result in higher rates of timely series completion.