Background: It is essential for immunization programs (IP) to avoid preventable vaccine waste, such as loss through improper storage. While package inserts define recommended storage temperatures, manufacturers provide advice about use after temperature excursions; however, thermostability data are not readily available to guide IP or providers. A 2007 survey conducted by the Association of Immunization Managers showed that IP considered vaccine waste a critical issue.
Objectives: To characterize storage failures resulting in vaccine waste and calculate the value of vaccine wasted in events identified by IP between July 13 and September 4, 2009.
Methods: An online questionnaire was developed to collect data on each incident involving the waste of either refrigerated or frozen vaccine identified during the study period. Waste during shipping was excluded. Each IP designated a primary contact who was trained on the use of the questionnaire.
Results: Thirty-nine of 50 states, 4 of 6 cities and 2 of 8 territories participated in the study. A total of 318 incidents were reported (range: 0-23 reports per IP). In 61 of 318 (19%) incidents, vaccine was left outside the storage unit. Combination refrigerator-freezer units were involved in 144 of 184 (78%) incidents where the type was known. Two hundred sixty of 305 (85%) incidents with known time out of range resulted from improper storage lasting 72 hours or less. The calculated value of publicly funded vaccine reported wasted during this 8-week period was $1,167,781.
Conclusions: More studies are needed to learn why combination storage units are so frequently involved in waste incidents. Data driven guidelines concentrating on conditions that do or do not necessitate vaccine waste after exposures lasting up to 72 hours would allow IPs to address most identified storage failures and possibly reduce financial losses resulting from waste.