Application of the remaining vaccine vial monitor life calculation to field temperature monitoring data to improve visibility into cold chain equipment performance.

Vaccine Vial Monitors (VVM) are used to estimate if a vaccine has been exposed to excessive hot temperatures. This endpoint measurement is useful in determining if a vaccine is safe to be administered to a patient, but it does not pinpoint where in the cold chain a vaccine was exposed to excessive heat. With the expansion and technological advancement of cold chain equipment temperature monitoring, it is now possible to remotely estimate VVM status as a vaccine moves through the cold chain. In the present study, we examine the application of the mathematical principles backing VVMs on real, continuous, temperature monitoring data in Africa. Results suggest that exposure to short bursts of hot temperature or long power outages may still allow for safe distribution of affected vaccines. The remaining VVM life calculation could improve managerial visibility into cold chain equipment performance allowing for better data-driven planning and maintenance decisions.