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

Abstract 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 15 years). To determine whether younger age (9 to 10 years of age) at HPV vaccine series initiation was associated with improved on-time completion rates compared to initiation at 11 to 12 years, 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 27 years) 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 15.0 years) using multivariate logistic regression. On-time completion of both 2 and 3 doses of the vaccine series by age 13.5 or 15.0 years was significantly associated with initiation at 9 to 10 years as compared to 11 to 12 years 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 10 years of age may result in higher rates of timely series completion.