6.4.1 The design of vaccine refrigerators
All electric powered refrigerators have a thermostat. The thermostat is a device that automatically responds to temperature changes by activating switches controlling the cooling equipment to maintain the refrigerator compartments at the correct temperature. You can alter the setting of the thermostat if the temperature of the refrigerator is found to be too high or too low when you check the thermometer. Gas or kerosene refrigerators are adjusted by altering the size of the flame.
To ensure that the refrigerator is effective for storing your vaccines, there are a number of guidelines that you should follow (Box 6.2).
Box 6.2 Guidelines for storing vaccines in a refrigerator
- Do not keep opening and closing the refrigerator door, since this raises the temperature inside the refrigerator.
- Do not put vaccines on the door shelves. The temperature in this part of the refrigerator is too warm to store vaccines, and when the door is opened the door shelves are instantly exposed to room temperature.
- Discard all expired vaccines (past their expiry date), or vaccines with VVMs that have reached or are beyond their discard point, or vaccines that have been reconstituted for more than six hours.
- Do not return reconstituted vaccines (BCG, measles) or opened PCV10 vials to the refrigerator. They should be discarded at the end of the immunization session or after six hours, whichever comes soonest.
- The refrigerator should not be packed too full. Approximately half of the total space inside should be left empty to allow air to circulate around the vaccines and diluents and keep them cool.
- Vaccines, diluents and ice-packs should ideally be kept in a separate refrigerator from other items. However, if your Health Post has only one refrigerator and you need to store other heat-sensitive supplies in it, such as drugs, ointments, serum and blood samples, be sure to label them clearly and keep them on a separate shelf from the vaccines and diluents.
- Food and drinks should NEVER be stored in a vaccine refrigerator.
There are a number of different types of refrigerator. Some front-loading refrigerators have one door, with a second freezing compartment inside. Others have two separate compartments, with different doors (look back at Figure 6.2, and see the diagram in Figure 6.12).
The two compartments shown in Figure 6.12 should be used as follows:
- The main compartment (the refrigerator), in which the temperature should be kept between +2ºC and +8ºC, is used for storing vaccines and diluents.
- The top compartment (the freezer) is used for freezing ice-packs. If the refrigerator is working properly, this compartment will be between –15ºC and –20ºC.
Notice the ‘use first’ box, for multi-dose vaccines that have been opened, or unopened vials that have been taken out for an immunization session but not used. These vials should be used before other vials.
Remember that you must not return opened vials of PCV10 vaccine to the refrigerator; it is a liquid vaccine without preservative and once it is opened any remaining vaccine in the two-dose vial should be discarded after six hours or at the end of the immunization session, whichever comes soonest.
Boxes containing vials with long expiry dates are stored at the back, and those with shorter expiry dates are at the front.
6.4 How to load cold chain equipment