Improper Temperature Control: A Global Problem

Globally, from Tunisia to the United States, underuse of digital temperature loggers leads to loss of product potency and efficacy for patients.

Globally, from Tunisia to the United States, underuse of digital temperature loggers leads to loss of product potency and efficacy for patients.

In Tunisia, where the climate is relatively hot, maintaining the cold chain is even more difficult than it is in other parts of the world.

However, counter to expectation, the primary challenge in Tunisia's vaccine cold chain are not primarily related to heat. Rather, Tunisian pharmacists have experienced substantial challenges through medical refrigerators that are too cold.

It is well known that many vaccines, in particular vaccines containing aluminum adjuvants, are particularly susceptible to loss of potency through freezing. Currently, an estimated 60% of refrigeration systems in Tunisia specifically meant for vaccines have registered temperatures lower than freezing.

To remedy this problem, Tunisian authorities recommend use of continuous temperature recording devices. As a result of these technologies, freeze alarms were reduced by nearly half from 116 to 83 between 2 comparable 2-month periods in a series of medical centers located throughout the country.

Use of temperature monitoring devices such as digital freeze alarms have helped reduce the risk of vaccine freezing by 40% in some health centers in regions of Kasserine in the southeast corner of Tunisia.

Many Americans may be surprised to learn that the problems with vaccine temperature control in Tunisia are also found in the United States.

Accidental freezing of vaccines were studied in a global metaanalysis published by Matthias and colleagues in a 2007 edition of the journal Vaccine. Using data collected from multiple sites around the world, investigators reported that 14% to 35% of in-transit vaccines were inappropriately exposed to freezing temperatures.

However, this is not a problem limited to less developed countries. In developed countries, such as the United States, 16.7% of vaccines were inappropriately stored at below-freezing temperatures at some point in transport. Similarly, during storage, 13.5% of refrigerators registered temperatures below the freezing-point threshold.

Considering that several organizations including the FDA, United States Pharmacopeia (USP), Healthcare Distribution Management Association (HDMA), and URAC all advocate use of digital temperature loggers, and in light of the high prevalence of in-transit losses due to improper temperature control, it is important for pharmacists to protect their patients by maintaining product integrity through temperature control with the best available technology on the market today.


  • Lloyd J, Lydon P, Ouhichi R, Zaffran M. Reducing the loss of vaccines from accidental freezing in the cold chain: The experience of continuous temperature monitoring in Tunisia. Vaccine. 2015;33(7):902-907.
  • Matthias DM, Robertson J, Garrison MM, Newland S, Nelson C. Freezing temperatures in the vaccine cold chain: a systematic literature review. Vaccine. 2007;25(20):3980-3986.