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Calibration Stability of Data Loggers Used for Vaccine Temperature Monitoring



Michal J. Chojnacky, Sam Smith, Bethany Rodman, Tobias Herman


Continuous temperature monitoring of vaccines during distribution and storage is critical to ensuring vaccination efficacy. Exposure to inappropriate storage temperatures can degrade vaccine potency, putting products and patients at risk if excursions go undetected. Digital temperature data loggers are widely used by U.S. vaccine providers to maintain a continuous record of vaccine storage temperature history. However, whether specific handling or use conditions contribute to measurement drift in data loggers is not well known. Here we show that data logger calibration status is largely unaffected by typical use conditions encountered at the vaccine provider level. Forty commercial digital data logger devices representing eight unique models marketed for use in vaccine temperature monitoring were evaluated in a two-year period during 2019-2021. The devices were calibrated upon receipt, subjected to trials designed to simulate typical use conditions, and then recalibrated periodically to evaluate potential measurement drift. Simulated use conditions included daily use in vaccine refrigerators and freezers, battery changes, local transport, cross-country shipment, and long-term storage. Out-of-tolerance calibration measurements were extremely rare, and the few failures we detected did not appear to be correlated with any of the use trials performed during the two-year study period. These findings support extending data logger recalibration intervals when paired with concurrent manufacturer-supplied device stability data and/or intermediate data logger verification checks performed in the field.
NIST Interagency/Internal Report (NISTIR) - 8457
Report Number


Calibration, Centers for Disease Control (CDC), cold chain, continuous temperature monitoring, digital data logger (DDL), ice melting point, stability, measurement drift, vaccine transport, vaccine shipment, vaccine storage, Vaccines for Children (VFC).


Chojnacky, M. , Smith, S. , Rodman, B. and Herman, T. (2023), Calibration Stability of Data Loggers Used for Vaccine Temperature Monitoring, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed May 22, 2024)


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Created March 6, 2023