Human Papillomavirus Vaccination in Washington State: Estimated Coverage and Missed Opportunities, 2006-2013.

Objective. Human papillomavirus (HPV) causes almost all cervical cancer in women and contributes to vaginal, anal, oropharyngeal, and penile cancer morbidity and mortality. Although vaccines effective in preventing up to nine types of HPV are available, vaccination rates are low nationally. We assessed HPV vaccination coverage by age, sex, and county using Washington State Immunization Information System data. Methods. We calculated on-time dose coverage by county and statewide among adolescents aged 11-12 years and assessed coverage by age 18 years. We calculated missed opportunities as the number of visits at which doses of other adolescent vaccines were administered without administration of the first dose of HPV vaccine (HPV1). Results. In 2013, HPV vaccination coverage estimates with one, two, and three doses (HPV1-3) for adolescents aged 11-12 years were 48.5%, 32.4%, and 18.3% among girls and 31.2%, 17.1%, and 8.1% among boys. The three-dose HPV vaccine coverage estimate increased to 40.1% among girls by age 18 but was unchanged for boys. Coverage estimates varied by age, sex, and county. One-third of eligible unvaccinated girls and two of five eligible boys aged 11-17 years had at least one missed opportunity to receive HPV1. Conclusion. Despite a recommendation to vaccinate adolescents aged 11-12 years, HPV vaccination is often delayed and coverage levels among all age groups are below national target levels. Improved understanding of the variability of HPV vaccination coverage rates by age, sex, and county can inform targeted interventions statewide.