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close this bookImmunization in Practice - Modules 1-11 (WHO; 2001; 242 pages) [FR]
View the documentIntroduction to the course
open this folder and view contentsModule 1: EPI target diseases
open this folder and view contentsModule 2: EPI vaccines
close this folderModule 3: The cold chain
View the documentAbout this module
View the document1. What is the cold chain?
View the document2. What cold-chain equipment is used in health centres?
View the document3. What cold-chain monitoring equipment is used in health centres?
View the document4. How to load cold-chain equipment
View the document5. Making ice packs
View the document6. How to monitor and adjust the temperature
View the document7. How to maintain cold-chain equipment
View the document8. The shake test to determine whether vaccine has been frozen
View the document9. Summary
open this folder and view contentsModule 4: Ensuring safe injections
open this folder and view contentsModule 5: Organizing immunization sessions
open this folder and view contentsModule 6: During a session: registering and assessing clients
open this folder and view contentsModule 7: During a session: preparing vaccines
open this folder and view contentsModule 8: During a session: giving immunizations
open this folder and view contentsModule 9: After a session
open this folder and view contentsModule 10: Communicating with parents and involving communities
open this folder and view contentsModule 11: Monitoring immunization coverage
View the documentBack Cover
 

2. What cold-chain equipment is used in health centres?

Different levels of the health care system need different equipment for transporting and storing vaccine and diluent at the correct temperature.

Central and regional stores need cold rooms, freezers, refrigerators and cold boxes (for transportation).

District stores need freezers, refrigerators and cold boxes.

Health centres need refrigerators, cold boxes and vaccine carriers.

The cold-chain equipment used in health centres includes the following:

2.1 Refrigerators

Health centre refrigerators may be powered by electricity, gas, kerosene or solar energy. Electric refrigerators are usually the least costly to run and the easiest to maintain but must have a reliable electricity supply.

Where the electricity or fuel supply is not reliable, ice-lined refrigerators can maintain the appropriate temperature for 16 hours without power if they operate with it for at least 8 hours a day.

Refrigerators have different capacities for storing vaccine and for freezing and storing ice packs. A refrigerator in a health centre should be able to hold:

• a one-month supply of vaccines and diluent; and

• a one- to two-week reserve stock of vaccines and diluent (an additional 25-50% of the one-month supply); and

• frozen ice packs or bottles of water in the bottom of the refrigerator to keep it cool if the power fails; and

nothing in half the total space available to allow air to circulate around the vaccines and diluent so as to keep them cool.

Figure 3-B: Two of the most common refrigerators


Absorption type refrigerator and freezer (PIS 3/28-M)


Compression refrigerator and icepack freezer (PIS E3/30)

2.2 Cold boxes

A cold box is an insulated container that can be lined with frozen ice packs to keep vaccines and diluent cold.

Cold boxes are used by health centre staff to collect and transport monthly vaccine supplies from district stores. They are also used to store vaccines when the refrigerator is out of order or being defrosted.

Different models of cold boxes have different vaccine storage capacities. Health centres usually need one or more cold boxes that can hold:

• a one-month supply of vaccines and diluent; and
• a one- to two-week reserve stock of vaccines and diluent.

In addition to their vaccine storage capacity, cold boxes are selected according to their cold life, the time taken for the temperature inside a cold box or vaccine carrier to rise from -3° C to +10° C without the lid being opened. Different models have a cold life of two to eight days.

The most suitable cold box for a particular health centre is determined by:

• the vaccine storage capacity needed;
• the cold life needed, this depending on the longest time that vaccine will be stored in the box;
• its weight, this depending on how the box will be transported, e.g., by motor vehicle or bicycle.


Figure 3-C: Small vaccine cold box

2.3 Vaccine carriers

Like cold boxes, vaccine carriers are insulated containers that can be lined with frozen ice packs to keep vaccines and diluents cold. They are smaller than cold boxes and easier to carry if you are walking, but they do not stay cold as long -only for 24-72 hours.

Vaccine carriers are used to transport vaccine and diluent to outreach sites and for temporary storage during health centre immunization sessions. In small health centres they are used to transport monthly vaccine supplies from the district store. In addition they are used to store vaccines when the refrigerator is out of order or being defrosted.

Different models of vaccine carriers have different storage capacities.

The type of vaccine carrier needed in a particular health centre depends on the number of vaccine vials, diluents and ice packs to be transported, the cold life needed, and the means of transport.


Figure 3-D: Large vaccine carriers

A foam pad is a piece of soft foam that fits on top of the ice packs in a vaccine carrier. When the carrier lid is open the foam pad keeps the vaccines underneath in a cool state. It also holds and protects vaccine vials during immunization sessions.

Note. Cups with ice and ice packs are no longer recommended for holding vaccine and diluent during sessions.


Figure 3-E: Foam pad in use

Do not put opened vials in the holes that are made in some ice packs. Use a foam pad.

2.4 Ice packs

Ice packs are flat, square plastic bottles that can be filled with water and frozen. The required number in a particular cold box or vaccine carrier varies.

Ice packs are available in two sizes:

• 0.6 litre for cold boxes;
• 0.4 litre for vaccine carriers.

Every health centre should have two sets of ice packs, one being frozen while the other is in use.


Figure 3-F: Icepacks

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