HPV vaccination: are we initiating too late?

BACKGROUND

Human papillomavirus (HPV) vaccination is recommended in early adolescence. While limited data suggest that patients frequently delay initiation of the three-dose series, age-based variability in initiation of HPV vaccination and its clinical relevance are not well described. Thus, this study aims to characterize HPV vaccination delay among adolescent and young adult females.

METHODS

This retrospective cohort study examined age at HPV vaccination initiation and missed opportunities for receipt of the first vaccine dose (HPV1) among 11-26 year-old females (n=22,900) receiving care at 16 urban academically-affiliated ambulatory care clinics between 2007 and 2011. Predictors of timely vaccination and post-licensure trends in age at HPV1 receipt were assessed using multivariable logistic regression and a generalized linear mixed model, respectively. Chlamydia trachomatis and Papanicolaou screening before HPV vaccination initiation, as markers of prior sexual experience and associated morbidity, were examined in a subcohort of subjects (n=15,049).

RESULTS

The proportion of 11-12 year-olds who initiated HPV vaccination increased over time (44.4% [2007] vs. 74.5% [2011], p<0.01). Initiation rates also improved among 13-26 year-olds. Thus, the mean age at HPV1 receipt remained unchanged between 2007 and 2011 (16.0 ± 2.7 vs. 15.9 ± 4.0 years, p=0.45). Spanish language was a positive predictor (AOR 1.62, 95% CI 1.05-2.48) of HPV vaccination initiation among 11-12 year-olds in 2011. The majority (70.8-76.4%) of unvaccinated subjects experienced missed vaccination opportunities. Of the subcohort, 36.9% underwent Chlamydia screening before HPV1 receipt (19.1% with ≥ 1 positive result). Of those with prior Papanicolaou screening (16.6%), 32.1% had ≥ 1 abnormal result.

CONCLUSIONS

These low-income, minority females frequently delayed initiation of HPV vaccination. Many had evidence of prior sexual experience and associated morbidity, placing them at risk of HPV-related complications. Promoting timely HPV vaccination and reducing missed vaccination opportunities are crucial.