We present a two-stage stochastic linear programming model to manage the inventory of vaccine vials in developing countries. In these countries immunization programs often involve targeted outreach services in remote locations. Organizations managing these programs are in need of tools which identify inventory replenishment and vaccine utilization plans to minimize costs and wastage while achieving greater coverage level. Wastage incurs when doses are discarded from open vials after their safe use time. We propose a model which identifies optimal portfolios of different sized vaccine vials, and corresponding vial-opening decisions in the face of uncertainty in patient arrival. This model is a two-stage stochastic program which we solve using an extension of the stochastic Benders decomposition algorithm (L-shaped method). Computational results on instances built using data from Bangladesh reveal that our solution approach outperforms the standard L-shaped method. Experimental results are used to develop simple and economic vaccine administration policies usable by healthcare administrators.
Submitted Aug 2016