OBJECTIVES: Two human papillomavirus (HPV) vaccines were licensed to prevent HPV infections, but the utilization remains low in the United States (US). Previous trend studies about HPV vaccine utilization in the US are scarce and their conclusions are subject to internal invalidities due to methodological flaws. This study aimed to reinvestigate the trend of HPV vaccine utilization including uptake, completion, and adherence by using more accurate measurement and sophisticated statistical methods.

METHODS: This was a retrospective cross-sectional study. Subjects aged 11-32 in the National Health and Nutrition Examination Survey 2011-2012 were extracted. Two constructs of the Andersen healthcare utilization model were adapted for variables selection. Heckman two-step sample selection models along with logistic and Poission regressions were performed to examine variables associated with vaccine uptake, completion, and adherence.

RESULTS: Among study subjects (weighted N= 92,290,848), 19.7% were HPV vaccine users. Factors positively related to vaccine uptake included being female, younger age, going to a doctor’s office or hospital for most healthcare services, and having Medicaid or other public insurance. Among HPV vaccine users, higher income was positively related to vaccine completion and adherence. Vaccine completion rate did not increase overtime. Nonetheless, subjects who received their first dose of HPV vaccine between 2008 to 2010 had better adherence, compared with subjects who received their first dose in 2006, the vaccine introduction year.

CONCLUSIONS: We observed disparities in HPV vaccine uptake, indicating that expanding insurance coverage to HPV vaccine and increasing vaccine access through primary care services could be efficient ways to improve the low HPV vaccine initiation rate in the US. Additionally, the increasing trend of HPV vaccine utilization observed from previous studies could be mistaken due to secular accumulation overtime. Because the vaccine completion rate actually did not increase over time, more efforts should be addressed to ensure vaccine completion.