Biomedical subjects

E C Sewell

Publications and source records attributed to E C Sewell.

3 recordsLinked to original sources

PubMed2001

"Reverse engineering" a formulary selection algorithm to determine the economic value of pentavalent and hexavalent combination vaccines.

INTRODUCTION: Combination vaccines with overlapping, noncomplementary components are being introduced to reduce the number of separate injections required to immunize children. A vaccine selection algorithm using operations research techniques was developed as a tool for vaccine purchasers to assemble formularies of monovalent and combination vaccines that would satisfy the recommended immunization schedule. The algorithm weighs distinguishing features of economic consequence among competing vaccines to achieve the lowest overall cost to payers and/or to society for immunization. This method was adapted here to solve for the purchase price of several hypothetical future pentavalent and hexavalent combination vaccines that would permit each to "win" a place in such a lowest cost formulary. METHODS: Integer programming and an iterative bisection search method determined the maximum "inclusion price" of 4 vaccines not licensed in the United States as of September, 2001 [diphtheria-tetanus-acellular pertussis (DTPa)-Haemophilus influenzae type b (HIB)-hepatitis B (HBV), DTPa-HIB-inactivated polio vaccine (IPV), DTPa-HBV-IPV and DTPa-HIB-HBV-IPV], in competition with 15 existing formulations of licensed vaccines for these diseases at their March, 2000, federal contract discount prices. Both 5-visit and 6-visit scenarios were studied. Different preparation costs were assigned to lyophilized powder ($1.50), liquid ($0.75) and prefilled-syringe ($0.25) formulations/packaging. Injection costs were varied stepwise from $5 through $45 for each dose administered, shifting from a payer's to a societal perspective. RESULTS: Overall inclusion prices (maximum price for each candidate vaccine to be included in a lowest cost formulary) ranged from $9 to $129 per dose depending on cost assumptions and usage frequency (values would be higher if competing against private-sector vaccine prices). The range was $27 to $68 per dose for DTPa-HIB-HBV, at optimal utilization to avoid extra vaccination. Similarly, as injection costs varied from $5 to $45, DTPa-HIB-IPV ranged from $28 to $75. With the same assumptions, DTPa-HBV-IPV would earn a place in a best value formulary at prices from $35 to $76. As expected the inclusion prices for hexavalent DTPa-HIB-HBV-IPV, $40 to $123, were higher (reflecting more economic value) than for pentavalents. When the assumed injection costs rose to > or = $8, the more expensive HIB-HBV and DTPa-HIB tended to appear in lowest cost formularies, because their cost premium over separate monovalent and trivalent products was outweighed by the savings from one fewer injection. CONCLUSION: Reverse engineering the vaccine selection algorithm provides a tool to demonstrate the economic value of new combination vaccines and to make pricing decisions.

Algorithms↗

PubMed1999

An integer programming model for vaccine procurement and delivery for childhood immunization: a pilot study.

The National Immunization Program of the Centers for Disease Control and Prevention has identified several challenges that must be faced in childhood immunization programs to deliver and procure vaccines to protect against the common preventable diseases. The biomedical challenge is how to combine and formulate products to take advantage of new vaccines without requiring additional injections. A programmatic challenge is to incorporate then into already crowded immunization schedules. The economic challenge is to make wise procurement choices from among a growing number of competing products. This paper reports the results of a pilot study using operations research methodologies to address the third of these challenges. The pilot is an integer programming model for procuring vaccines for a set of childhood diseases. The model is studied under various scenarios (minimum total cost, next lowest total cost, maximum total cost, minimum total cost with all manufacturers represented). The results of this pilot study demonstrate how a practical set of operations research tools can be developed to guide vaccine selection and procurement, which might stimulate the development of innovations in new vaccines to meet the challenges of disease control through immunization.

Centers for Disease Control and Prevention, U.S.↗

PubMed1998

Addressing the challenges to immunization practice with an economic algorithm for vaccine selection.

The biotechnology revolution is producing a growing bounty of new vaccines which pose difficult choices in selecting among many products. Some major public and private purchasers of vaccine may offer individual physicians and clinics their choice in assembling vaccine inventories. Others might purchase only a limited stock of products that would satisfactorily immunize a typical child. In either case, current vaccine selection decisions are based principally on purchase price alone without systematic consideration of other factors of fiscal consequence. As a potential tool for decision making, we developed an economic algorithm for vaccine selection that would minimize the overall costs of disease control through immunization by considering: (1) purchase price, (2) number of doses needed, (3) preparation time, (4) route of administration, (5) cold storage needs, (6) shelf life, (7) earliest age of full immunity, (8) adverse events frequency, and (9) efficacy of protection. To demonstrate the algorithm, variables (1) to (4) above were incorporated into a pilot binary-integer linear programming model that satisfied the recommended immunization schedule for diphtheria, tetanus, pertussis, Haemophilus influenzae b, and hepatitis B, using eleven vaccines (DTaP, DTaP-Hib, Hib, HepB and Hib-HepB) from four manufacturers. Five (or six) opportunities to vaccinate were modeled at (1), 2, 4, 6, 12-18, and 60 months of life, assuming US$40 per clinic visit, $15 per injection, and $0.50 per minute of nurse preparation time. Vaccine costs were varied using actual March and September 1997 US Federal vaccine prices, as well as estimates for unpriced new vaccines. Over 16,000 distinct vaccine stocking lists by vaccine type and brand were possible. Including a 1-month visit, the lowest-cost 'solution' of the algorithm was $529.41 per child in the March cost-assumption case, and $490.32 in the September one (both included four doses of DTaP-Hib, three HepB, and one DTaP). Without a 1-month visit, the lowest-cost solution in the March case cost $486.67 (four DTaP, two Hib-HepB, one DTaP-Hib, and one HepB), while the September case cost $450.32 (four DTaP-Hib, three HepB, and one DTaP). Ensuring at least one product was selected from each of the four manufacturers increased costs about $13.00, and the needed injections rose from eight to nine. The most economical selection of vaccines to use cannot be intuitively predicted, as permutations are large and solutions are sensitive to minor changes in costs and constraints. A transparent, objective selection method that weighs the economic value of distinguishing features among competing vaccines might offer the 'best value' to vaccine purchasers, while also creating strong market incentives for continuing innovation and competition in the vaccine industry.

Adolescent↗