Background: Human papillomavirus (HPV) results in 37,000 new cancers each year. HPV-attributable cancers are preventable through vaccination with the completion of the HPV series encouraged by age 13 years. Public uptake has been lower than expected. Blue Cross Blue Shield of Michigan (BCBSM) implemented clinical programs to address low vaccination rates.
Objective: To compare the proportion of adolescent members who completed the HPV vaccine series before vs after implementation of clinical programs.
Methods: Retrospective, observational study of BCBSM commercial medical claims for members aged 9 to younger than 14 years. Data were divided accordingly: (A) pre-intervention (2019), (B) academic detailing (2022), and (C) academic detailing and provider incentive (2023). Years 2020 and 2021 were excluded to avoid impact from the COVID-19 pandemic. The primary outcome compared the proportion of members who completed the HPV vaccine series for Cohorts B and C compared with Cohort A. Secondary outcomes included the proportion of members who completed the first dose, the time between the dose due date and when the dose was received, average age at series completion, and dose 1 and 2 completion by month. Data were assessed using chi-square and independent t-tests.
Results: Member baseline characteristics were similar, with the majority aged 11 to younger than 13 years, male, White, and having an urban residence. For Cohorts A, B, and C, the proportion of HPV series completers were 15.3%, 15.2%, and 15.2%, respectively. The proportion of those who received only 1 dose was 15.8%, 15.6%, 15.5%, respectively. Cohorts B and C completed the series later compared with Cohort A, with the remaining time until due date as follows: 38 days (Cohort A), 8 days (Cohort B), and 4 days (Cohort C). Compared with Cohort A, Cohorts B and C had more members who received doses 1 and 2 more than 1 year apart: 8.1% (Cohort B) and 8.4% (Cohort C) compared with 6.3% (Cohort A). The average age of series completion was 12 years. August was the most popular month to receive doses 1 and 2 across all cohorts.
Conclusions: The difference observed between cohorts for the proportion of members who completed the series was not statistically significant. Cohorts B and C completed the series later compared with Cohort A, and a higher proportion received doses 1 and 2 more than 1 year apart. Although the years 2020 and 2021 were not included, lasting impact from the pandemic may have influenced study results; however, BCBSM's efforts may have mitigated the impact of the national decrease seen in HPV vaccination among in-state members.