ATLANTA - A pilot study for the Centers for Disease Control and Prevention (CDC) could help vaccine purchasers make decisions and save money.
The study is part of an effort to maintain high childhood immunization rates despite an increasingly demanding immunization schedule, with requirements that leave many children missing inoculations and facing health risks that multiply medical costs. The pilot study weighs the economic value of distinguishing features among competing vaccines, such as new combinations that might reduce the number of injections or clinical visits.
"Several studies indicate that many providers and parents are reluctant to administer more than two, and especially more than three, injections during a single visit because of the child's fear of needles and pain," said Bruce G. Weniger, MD, MPH, assistant chief, Vaccine Development for the Vaccine Safety and Development Activity, National Immunization Program.
This pilot study focuses on a potentially costly part of the immunization system: purchasing vaccines. The pilot study looked at vaccines for five potentially serious childhood diseases: hepatitis B (HepB), Haemophilus influenzae type b (Hib), diphtheria, tetanus and pertussis (DTP, DTaP).
Sheldon H. Jacobson, MD, from Virginia Tech in Blacksburg, Va., created an "integer programming model" - a mathematical model - that more efficiently compares prices and performance of competing vaccines from different manufacturers.
Jacobson and Weniger and their colleagues developed an algorithm that would permit adding larger numbers of vaccines that are expected in the future. The pilot is unique because it brings a practical set of operations research tools to vaccine selection and procurement.
Jacobson noted that with new vaccine brands and types rapidly being introduced, often with differing features and in combinations with overlapping but nonidentical components, it becomes difficult for vaccine purchasers to select the most efficient inventory to minimize costs.
"State health departments, HMOs and other large vaccine purchasers are facing daunting decisions because of the surfeit of choices becoming available," he said. "I think the CDC realized that developing sophisticated but user-friendly tools for helping make such decisions would be a valuable service to its constituents in the immunization community."
Weniger added that one desired outcome of the vaccine selection algorithm is to provide incentives for industry to invest in research and to produce more flexible, effective, convenient and otherwise innovative products.
Reducing expense in the vaccination process is tied to trimming several costs: the price of multiple visits to doctors or clinics to receive inoculations, the price of the vaccine, the cost of storing extra vaccines that are eventually discarded and the cost associated with medical staff. To demonstrate the model, the CDC estimated the expense of each visit to be $40, each injection $15 and medical staff time for mixing vaccines as 50 cents per minute.
Solving the "procurement and delivery problem" required the development of a model to determine the most economically sound package of existing vaccine types (single-disease and in combinations) and manufacturer brand that should be procured and the months in which these vaccines should be administered to satisfy the existing recommended childhood immunization schedule, as well as to cope with a number of constraints.
The pilot focused on four vaccine manufacturers that produced 11 different vaccine types; eight individual vaccines and three combinations. It looked at two cases of when one of the vaccines, hepatitis B, would be delivered: case 1 was shortly after birth, most likely in the hospital after delivery; and case 2 was in the second month of life, such as, at a clinic during a child's first set of vaccines. The model was run to compare four optimization goals: minimum total cost, next lowest total cost, maximum total cost, and minimum total cost with all manufacturers represented.
Among the study's findings was that in case 1, the difference between the minimum cost solution and the next lowest cost solution was $1.41. Therefore, by identifying and purchasing the more economical package of vaccine that will be distributed to millions of children, the health system could potentially save millions of dollars, Weniger said.
However, "The underlying principle is that purchase price alone is but a small proportion of the total costs of disease prevention through immunization, and that initially more expensive vaccines may represent a better value in lowering the overall costs because of various potential distinguishing features in their delivery and performance," Weniger added.
The researchers examined a potential industrial policy to keep all four current vaccine manufacturers in the loop, and thus perhaps avoid further consolidation in the industry with resultant higher prices. They found such a policy would raise overall costs about $13 per child compared to not guaranteeing all manufacturers at least some share of the market.
"One limitation of the algorithm is that it recognizes only those factors for which economic values can be reasonably assigned. Another limitation is that vaccine prices change frequently, and thus prior lowest cost inventory solutions might soon become obsolete. But it might be inefficient and confusing for immunization programs and providers frequently to revise their inventory lists," Weniger said.
For more information:
- Jacobson S, Deuson R, Weniger BG. An integer programming model for vaccine procurement and delivery for childhood immunization: a pilot study. Health Care Management Science. January 1999.
- Weniger BG, Chen RT, Jacobson SH, et al. Addressing the challenges to immunization practice with an economic algorithm for vaccine selection. Vaccine. November 1998.
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