Community health workers in global health: scale and scalability.

Community health worker programs have emerged as one of the most effective strategies to address human resources for health shortages while improving access to and quality of primary healthcare. Many developing countries have succeeded in deploying community health worker programs in recognition of the potential of community health workers to identify, refer, and in many cases treat illnesses at the household level. However, challenges in program design and sustainability are expanded when such programs are expanded at scale, particularly with regard to systems management and integration with primary health facilities. Several nongovernmental organizations provide cases of innovation on management of community health worker programs that could support a sustainable system that is capable of being expanded without being stressed in its functionality nor effectiveness--therefore, providing for stronger scalability. This paper explores community health worker programs that have been deployed at national scale, as well as scalable innovations found in successful nongovernmental organization-run community health worker programs. In exploration of strategies to ensure sustainable community health worker programs at scale, we reconcile scaling constraints and scalable innovations by mapping strengths of nongovernmental organizations' community health worker programs to the challenges faced by programs currently deployed at national scale.