More than three years have passed since HPV vaccine first became available in the U.S. Current HPV vaccine utilization levels among adolescent females are still well below national vaccination targets. Low utilization levels call for identification of policies or procedures that may increase vaccine utilization among this population. To our knowledge, ours is the first analysis to examine nationally whether school mandates for other adolescent-targeted vaccines (Td and/or Tdap) are associated with differences in HPV vaccine utilization.
We found that HPV vaccine series initiation was substantially higher among adolescents residing in states where a mandate for a tetanus-containing vaccine was already enacted. Though causality cannot be determined by our results, this finding suggests that a carry-over effect from Td/Tdap to HPV vaccination may be occurring in many locales. Our results are preliminary however, and should be interpreted with caution. It will be important in future studies to examine in greater detail if and how such carry-over effects happen. An additional limitation of our study is that we did not assess any state demographics and how these may have been associated with vaccination uptake, and we were also not able to examine within-state variability in vaccination rates which can be affected by local factors.
One can hypothesize many ways in which a Tdap/Td mandate could have indirect effects to increase adolescent HPV vaccine utilization. For example, school mandates for one adolescent vaccine may lead both parents and providers to place a higher importance on adolescent vaccination more generally, which in turn leads to increased community demand for HPV vaccination and increased likelihood that a provider will have the vaccine available. From a provider perspective, implementing office procedures to stock, provide and track a mandated vaccine (i.e. Tdap) may facilitate the stocking and provision of other, non-mandated vaccines like HPV. A carry-over effect could also have an effect at a broader societal level. In states with school mandates for tetanus-containing vaccines, adolescent vaccination may be more “normalized” from a societal perspective. This could create parental and adolescent expectations for vaccination at adolescent preventive care visits, and perhaps even increased availability of the HPV vaccine through insurance plans or other resources (e.g. Health Department) in the area. Additional work will be needed to determine the extent to which mandates for other vaccines indirectly affect HPV vaccine utilization, and how this compares to the direct effects from HPV-vaccine-specific mandates themselves. Given that two locales (DC and VA) have enacted school mandates for HPV vaccination for the 2010–2011 school year, this comparison will soon be possible. Until the controversy surrounding HPV vaccine-related school mandates has subsided, carry-over effects from mandates for other adolescent vaccines may help augment HPV vaccination rates among adolescents.