BACKGROUND:
The vaccine formulary selection algorithm (www.vaccineselection.com), developed with support from the CDC, uses operations research tools 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 economic aspects of immunization. It also allows manufacturers to study prices at which products win a place in the best-value formulary.

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 set of vaccines to satisfy the recommended childhood immunization schedule.

METHOD:
The website comprises a core of integer programming in C and C#, an SQL database, and an ASP.NET front end. The website's look and feel, database connectivity, user authentication, response speed, and user friendliness have recently been improved.

RESULT:
Recent enhancements make it easier for users to identify lowest-cost formularies that satisfy all currently recommended antigens. New vaccines and prices can be added by users for consideration by the algorithm. A significant and growing number of website visitors continue to use the algorithm.

CONCLUSION:
The web-based vaccine formulary selection algorithm provides a convenient tool for economic analysis by vaccine purchasers and immunization providers. It can be highly valuable in assessing how new combination vaccines impact the cost and complexity of pediatric immunization formularies.

LEARNING OBJECTIVES:
Understand the value of using the algorithm to support vaccine purchasing decisions by buyers and pricing decisions by manufacturers, and the benefits of recent website enhancements.