Agenda setting for essential medicines policy in sub-Saharan Africa: a retrospective policy analysis using Kingdon's multiple streams model.

We found that effective implementation of an essential medicines policy under PHC was constrained by prioritization of trade over public health in the politics stream, inadequate systems thinking in the policy stream and promotion of economic-oriented reforms in both the politics and policy streams. These lessons from the PHC era could prove useful in improving the approach to contemporary UHC policies.