BACKGROUND:
The vaccine formulary selection algorithm (www.vaccineselection.com) uses operations research to select vaccines among increasing arrays of new monovalent and combination vaccines with overlapping, non-complementary antigens. It determines a formulary of lowest overall cost by considering not only purchase price but also the value of fewer doses and injections and other vaccine features of economic value. It also allows manufacturers to see the point when lower price wins a place in a best-value formulary in competition with existing products.

OBJECTIVE:
To provide a user-friendly interactive website for vaccine buyers to set their own parameters for valuing vaccine features in choosing the most economical group of vaccines which satisfy the recommended childhood immunization schedule.

METHOD:
A core of integer programming was linked with a C# and ASP.NET front end and a faster search engine. Recent enhancements to value longer shelf lives account for the costs of vaccine wastage by expiration.

RESULT:
With these enhancements, the website identifies lowest-cost formularies that satisfy all recommended antigens as of January 2004, including influenza. New vaccines and prices can be added easily by users for consideration by the program. As of January 2004, a total of 650 unique visitors and 1100 visits to the website had been logged. Manufacturers can "reverse engineer" the algorithm to determine important pricing points for new products.

CONCLUSION:
As new vaccines appear with enhanced features such as needle-free delivery and extended shelf life, their economic value can be weighed by enlightened buyers using the algorithm. Manufacturers can also judge how competitive future products may be in justifying R&D investment.

LEARNING OBJECTIVES:
Understand how operations research can be used to support vaccine purchasing decisions by buyers and pricing decisions by manufacturers.