DALLAS - In 1998, $608 million in public funds were spent to purchase 62 million doses of childhood vaccines through Centers for Disease Control and Prevention (CDC) contracts, according to Sabeena Setia, MPH, Vaccine Development Fellow in the Vaccine Safety and Development Branch, National Immunization Program (NIP), CDC. "Since accountability for handling vaccines occurs primarily at the state level, we lack a national overview of how much of this vaccine is wasted," said Setia.
The CDC began studying vaccine wastage to assist states in identifying and reducing spoiled or expired doses used in public health clinics and the Vaccines for Children program, which supplies many private immunization providers. "With costs increasing with the introduction of expensive new vaccines, we need a better understanding of how much is wasted, and why," Setia said. In a presentation at the 33rd annual National Immunization Conference, held here in June, she reported that the purchase price of vaccines to fully immunize a typical child from birth to 16 years of age according to the recommended immunization schedule (excluding rotavirus) is currently about $188 for public purchasers and $355 for private ones.
Although some degree of wastage is inevitable, there are no known reports documenting how many vaccine doses are spoiled, expired or otherwise unable to be used each year in the United States. To estimate this, several branches within NIP, cooperating states, and vaccine manufacturers participated in a preliminary study to quantify the phenomenon. They tabulated and analyzed limited existing data from both public and private sources to assess the overall magnitude of the problem and the relative frequency of different forms of wastage.
"In an ideal analysis we would like to know all possible reasons why a vaccine dose could not be used," said Setia. These include doses which have passed their expiration date, those spoiled by a refrigeration failure or other break in the "cold chain" between manufacturer and patient, and physical damage, such as being dropped, broken, crushed, or losing a label.
"A cause that is harder to measure is when fewer than the nominal number of doses in a multidose vial are administered." This might occur when a vial that is not empty is discarded, or when a provider overfills the syringe and squirts out some of the vaccine to get the proper dose, she said.
"Two categories of wastage that we did not anticipate, but some states kept track of, were `refused or spit-out' and `prepared too many doses,'" said Setia. Other wastage categories were vaccines missing in transit, and inventory that was lost or unaccounted for.
State and local immunization programs and vaccine manufacturers were approached to determine availability of vaccine wastage data and to ask for their participation, said Setia. Data from five non-randomly selected unidentified states, designated A through E, in several U.S. regions, were analyzed.
To calculate their wastage rates, the numerator was the number of doses reported wasted by any specific cause, and the denominator was the total number of doses distributed to a state or its providers during a specific time period. Data were also analyzed on wasted vaccines returned by immunization providers to three U.S. vaccine manufacturers for replacement of privately-purchased vaccine, or for excise tax credit for publicly-purchased doses which lack return privileges.
Because states classify causes of wastage differently, combining their data to determine the most common reasons was difficult, Setia said. A uniform classification system does not exist. For example, states A and B use a broad category of "spoiled," whereas others are more specific.
All states did maintain a separate category for "expired" vaccines, and wastage rates due to expiration ranged from 0.4% in state D to 2.0% in state B. The rates for all other forms of wastage (spoiled/lost/other) ranged from 0.5% in state E to 3.4% in state A. When all causes are combined, the reported total wastage in the five states ranged from 1.4% to 5.3%.
The annual cost of this wastage was roughly estimated by multiplying the average cost per dose, $12.51 in the public sector, by the reported number of doses wasted. These estimates ranged from about $15,000 in a small state, B, to $1.2 million in a large one, D.
"The vaccines wasted in all five participating states were worth about $3 million," Setia said. "It is important to remember that these losses are from only five among 64 state and local immunization programs, and thus represents the tip of an iceberg."
To estimate wastage from vaccines returned for all causes to manufacturers for replacement or credit, the returned doses were divided by a denominator of the number distributed in the same time period. Returns ranged from 0.8% to 9.2%, of which about half comprised influenza vaccine used primarily in adults. "These rates represent a mix of both publicly and privately purchased vaccines," Setia said. Using individual vaccine prices and estimating the unknown mix of public versus private doses returned, the estimated total annual value of returned doses was $51 million.
As a result of the study, Setia said, the CDC plans to propose uniform classifications for specific types of wastage to facilitate surveillance of the phenomenon, and to develop protocols for prospective studies to better measure it. A collateral goal will be to use the data to derive the economic value of future vaccine innovations, such as products with longer shelf lives or with improved heat stability that might not require refrigeration. In any case, she concluded, "it is hoped the work will identify those forms of wastage most amenable to reduction and prevention and thus help improve the management of vaccine inventories by immunization programs and providers."
For more information:
- Setia S. Vaccine wastage in the United States. A preliminary report. Workshop D4. Presented at the 33rd Annual National Immunization Conference, June 22-25, Dallas.
- Bell KN. Monitoring vaccine storage and handling in private provider offices. Workshop D4. Presented at the 33rd Annual National Immunization Conference, June 22-25, Dallas.
You can express your views on this article, or other relevant themes, in the Infectious Diseases in Children Specialty Forums.