Optimizing timing of adolescent vaccines: Impact of initiating HPV vaccination before Tdap or meningococcal vaccination on timely completion of the HPV vaccine series.

To explore the impact on timely series completion of initiating the HPV vaccine series prior to other vaccines in the adolescent platform (Tdap or meningococcal vacccines), we created a cohort of children aged 9 in 2015 who were continuously enrolled through the age of 13 (2019) from a national administrative database of employee-sponsored insurance in the United States (MarketScan). Logistic regressions were used to predict the odds of HPV vaccine series completion among those who started the series prior to, concurrent with, or after receiving Tdap or meningococcal vaccination. The cohort included 100,857 eligible children. Compared with adolescents who received their HPV and Tdap or HPV and meningococcal vaccinations concurrently, those who received HPV prior to other vaccines had higher completion (aOR = 1.38 for Tdap, aOR 1.62 for meningococcal), while those who received their HPV vaccination after other vaccines had lower odds of HPV vaccine series completion (aOR = 0.68 for Tdap, aOR = 0.62 for meningococcal). Other factors associated with series completion included female sex, residing in an urban (vs. rural) area, residing in the Northeast, and receiving primary care from a pediatrician (vs. family medicine physician). These data indicate that beginning the HPV vaccine series prior to the adolescent platform may improve on-time series completion.