Study IDs More Efficient Vaccine Supply Chain Processes

New research identifies potential processes for drug manufacturers and public health officials to reduce pediatric vaccine supply shortages and still maximize immunity from disease by children. Researchers at University of Illinois at Urbana-Champaign (UIUC) and Rochester Institute of Technology (RIT) in New York have developed a mathematical framework to better understand the implications of the pediatric vaccine stockpile levels.

Industrial engineers Sheldon Jacobson of UIUC and Rubén Proaño of RIT, who specialize in operations research, and Janet Jokela, a specialist in public health and infectious diseases at UIUC, published this work in the online edition of the November 2010 issue of the Journal of Industrial and Management Optimization. The research was funded by a grant from the National Science Foundation.

The United States maintains a six-month supply of common pediatric vaccines in the Pediatric Vaccine Stockpile Program administered by the Centers for Disease Control and Prevention. The stockpile helps ensure protection from diseases, such as the flu, polio, and diphtheria, despite interruptions in vaccine production. Stockpiles must be replenished as the vaccines are used or expire, and, because the manufacture of vaccines is a laborious and unreliable process, health officials must place orders for new vaccines up to a year in advance.

The researchers’ model for setting stockpile levels adapts the “utility maximization problem” (UMP). One everyday example of a UMP is the set of considerations involved in choosing a car — such as cost, performance, and gas mileage — that a buyer must weigh based on relative importance. The best car for a particular buyer will depend on his or her preferences.

The mathematical framework adapted from the UMP allows health officials to see the optimal stockpile levels for different initial conditions and preferences of public health officials. Through eight hypothetical scenarios, the researchers demonstrated how different approaches to managing stockpiles of six pediatric vaccines have different implications for public health. When initial conditions are poor, due to low stockpiles and/or low vaccine coverage, the scenarios revealed that the preferences of the public health decision-maker can significantly affect what the optimal stockpile size would be.

Jacobson says the findings support the idea of one size — the standard six-month stockpile — may not fit all requirements, with some vaccines needing more or less than six months’ supply on hand. He adds the model also demonstrates that the vaccine stockpile could be used strategically to increase vaccine coverage or to protect society from disease outbreaks.

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