Human Papillomavirus Vaccination in Washington State: Estimated Coverage and Missed Opportunities

BACKGROUND:  Human papillomavirus (HPV) causes almost all cervical cancer in women and contributes to vaginal, anal, oropharyngeal, and penile cancer morbidity and mortality. A quadrivalent vaccine that is effective in preventing infection from four types of HPV is available for use in both females and males, and a bivalent vaccine is available for use in females. However, HPV vaccination rates remain low nationally. We sought to assess HPV vaccination coverage by county, age, and gender in Washington State using state immunization information system (IIS) registry data.

METHODS:  Vaccination doses administered according to ACIP recommendations to Washington residents and recorded in the IIS were included in the coverage numerator; census estimates were used for the denominator. On-time dose coverage was calculated among male and female adolescents aged 11 to 12 years to assess compliance with ACIP guidelines. Coverage by age 18 years was also assessed. Missed opportunities were calculated as the number of visits at which doses of other adolescent vaccines were administered, without corresponding administration of the first dose of HPV vaccine.

RESULTS:  In 2013, HPV vaccine coverage estimates with one, two and three doses for adolescents aged 11 to 12 years were 48.5%, 32.4%, and 18.3% in females and 31.2%, 17.1%, and 8.1% in males. Three dose coverage estimates increased to 40.1% in females by age 18, but remained stagnate for males. Coverage estimates and completion rates varied by age, sex, and county. One-third of eligible, unvaccinated females and two of five eligible males aged 11-17 years had at least one missed opportunity to receive their first dose of HPV vaccine. 

CONCLUSIONS:  Despite a recommendation to vaccinate both males and females aged 11-12 years, coverage was significantly higher among females and among adolescents aged 13-18 years. Improved understanding of the variability of HPV vaccination coverage rates by sex, age, and county can inform targeted interventions statewide.