Appendix 41. Cold chain monitoring tools

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    Successive temperature fluctuations can reduce the efficacy of the vaccine. It must therefore be kept at a constant temperature between 2 °C and 8 °C (or according to the manufacturer’s recommendations) from production to administration.


    Rigorous temperature monitoring is critical for detecting any breaks in the cold chain:

    • International transport: temperature recorder, cold chain monitoring card;
    • Refrigerator: thermometer, temperature monitoring sheet and Stop!Watch® card;
    • Transport to the vaccination site: thermometer;
    • Vaccines: vaccine vial monitor (VVM).


    Any cold chain problems should be noted and reported to the person in charge so that a decision can be made on whether to use the vaccines.

    41.1 Stop!Watch® card with Freeze-tag®

    This card is equipped with irreversible temperature monitor and freeze indicators. It is used to verify the temperature inside a refrigerator.
    Place the card in the refrigerator 60 minutes before activating it by pulling the tab.
    It should remain in the refrigerator at all times.
    The Stop!Watch® card is a supplementary monitor that does not eliminate the need to fill in the temperature monitoring sheet 2 times daily.


    • A heat-sensitive indicator with four windows (A, B, C, D):
      • Windows A, B and C turn gradually and irreversibly blue when the indicator is exposed to temperatures above 10 °C, as a function of the exposure duration and temperatures.
      • Window D turns blue within 2 hours when the indicator is exposed to temperatures above 34 °C.
        On the front of the card, write:
        • the date it was put in service;
        • the name of the storehouse;
        • the status of the freeze indicator;
        • the date on which a window (A, B, C or D) turned blue.


    On the back of the card, write:

    • the inspection date;
    • the status of the indices (A, B, C or D);
    • the status of the freeze indicator;
    • the supervisor’s name.


    • A freeze indicator (Freeze-tag®):
      When the indicator is exposed to a temperature of 0 °C for more than 1 hour, the screen changes from “OK” to “ALARM”.

    Any colour change or triggering of the freeze indicator should be noted on the back of the card.

    41.2 Vaccine vial monitor

    A dot that changes colour (darkens) irreversibly when the vaccine is exposed to heat for a given amount of time. The dot is applied to the cap or label of the vaccine vial or ampoule.


    All vials for which the square is lighter than the surrounding disk can be used; however, vials whose square has begun to change colour should be used first.