What determines government attention to emerging health issues? We draw on research in agenda setting and policy diffusion to explore the determinants of public health attention in the fifty American states. We find that intergovernmental influence has a strong and consistent influence over state attention to tobacco and vaccines from 1990 to 2010. While national attention to tobacco or vaccines also sparks attention in the states, this effect is smaller than the internal impact of gubernatorial attention and the horizontal influence of neighboring state attention. We find some support that problem severity matters; however, these results are highly dependent on the measures used. Finally, we find no evidence that interest groups influence the attention that states pay to tobacco or vaccines. Our results suggest that institutions play a critical role in explaining government attention to health policy.