Taken together, the results for adults suggest that vaccine that was broadly accessible may have facilitated higher coverage. This could be because high-risk adults may not visit internists or specialists frequently enough to be vaccinated in this time period; because specialists traditionally have had less focus on vaccinating so patients may have looked elsewhere for vaccine, or because the cost in some settings was lower. For high-risk adults,

the percent medically underserved is also negatively associated with coverage, which may also help explain the positive impact of open access locations and pharmacies. The number of shipments per ship-to site was positively associated with coverage for children but not for high-risk adults. For children, this may reflect repeated shipments to locations such as local health departments, mass clinics, or pediatricians who may have offered repeated clinics. Some health departments monitored GDC-973 usage and distributed

more vaccine to providers who were depleting vaccine supply faster, which is another potential hypothesis. The maximum number of sites to which vaccine could be directly shipped through the centralized distribution system was positively associated with vaccination coverage for both children and high-risk adults, a finding also observed for overall adults [3]. Because the number of ship-to-sites allowed for each state was based on a formula that included the population size as well as the number of existing VFC providers, IPI-145 molecular weight this measure may reflect a more robust healthcare infrastructure. The expansion of vaccine availability to the general public by December 4th was associated with lower coverage for high-risk adults. Early expansion could have resulted in less access for high-risk adults, especially if a state had sequential priorities (e.g., children first, then high-risk adults). However, because in most states, decisions about when to make vaccine available beyond the initial target groups were based on perceived demand for vaccine, e.g., as ascertained from provider vaccine Megestrol Acetate orders

and attendance at public clinics, so the decision to expand early could reflect lower demand in those states. Coverage for high-risk adults was positively associated with uptake of seasonal vaccine for high-risk adults in 2007–2008, as it was for adults overall [12]. This could be because the administration sites for adults were similar to past seasonal influenza campaigns or it could reflect use of preventative services. In contrast, the lack of association for children could reflect the fact that vaccine administration sites differed from past seasons with school vaccination playing an unprecedented role during this influenza vaccination campaign. A second hypothesis for children is that the increased focus on them as a priority group served to motivate their vaccination by caregivers or providers.