The influence of free quadrivalent human papillomavirus vaccine (HPV4) on the timely completion of the three dose series.

Objective: Economic incentives can positively influence social determinants to improve the health care of the uninsured and underserved populations. The aim of this study was to determine if free HPV4 vaccine would lead to on-time series completion in our safety net health care system in the US Midwest.

Methods: A nested retrospective cohort study of females receiving HPV4 vaccine between 2006 and 2009 was conducted. Patient characteristics and payor source for each of the three HPV4 doses were abstracted from electronic records. Logistic regression was used to predict on-time completion rates.

Results: The proportion of adolescent and adult females completing three on-time HPV4 doses was equal (21% (28/136) vs. 18% (66/358), respectively) from among the 494 females receiving 927 HPV4 doses in this study. No adolescent receiving free HPV4 vaccine completed three doses. Grant sponsorship of at least one HPV4 dose among adults did not predict three dose on-time completion (OR=1.56, 95%CI: 0.80, 3.06). Neither was adult grant sponsorship of HPV4 significant when analyzing exclusive payor sources vs. a combination of payor sources (OR=0.72, 95%CI: 0.10, 5.17).

Conclusions: Free HPV4 vaccine does not influence the on-time completion rates among adults.