Cold Chain
Suitable Containers for Vaccine Transportation

There are several alternatives for the shipment of temperature-sensitive cargo:

Refrigerated (Multimodal) Containers

A refrigerated (multimodal) container or reefer, is a shipping container equipped with an integrated refrigeration unit for the transportation of temperature-sensitive cargo. They rely on external electrical power provided from the ship, the quay or the trailer. These type of containers are suitable for large-scale shipments and when the journey requires changing modes of transport (i.e. road-sea-road), normally over long distances.

Refrigerated containers are rarely used for vaccine transport. For long distances or inter-continental movements, vaccines are commonly air-shipped in cold storage containers, which are either actively powered or passively kept cold. Therefore, refrigerated multimodal containers are not advised for transportation of vaccines.

Refrigerated Vehicles

A refrigerated vehicle is a van or truck with a thermally isolated cargo compartment, equipped with a mechanical refrigeration system for road freight transport at specific temperatures.

Such vehicles are utilised for large-scale transport of vaccines from the manufacturer to primary/central stores and in certain context for bulk transport between primary/central stores and secondary stores. Refrigerated vehicles are commonly run by specialised logistics operators. Please review the checklist for contracting refrigerated vehicles in the road transport section of this guide. 

Still, the high cost of refrigerated vehicles and their tendency to suffer mechanical breakdowns, have prevented many developing countries from using this transport method for regular deliveries. Additionally, when using a refrigerated vehicle in such contexts, it is recommended cold packing provisions to protect vaccines in case of vehicle breakdown.

Given that some cold boxes, if properly loaded, have enough cold life to cover transportation needs at national level, the use of refrigerated vehicles for bulk transport of vaccines is also discouraged if reliable infrastructure is not accessible.

Portable Passive Vaccine Containers

A portable passive vaccine container is a container that maintains a temperature-controlled environment inside an insulated enclosure, generally without thermostatic regulation, using frozen ice-packs, conditioned ice-packs, cool water-packs or warm water-packs. In this guidance, it includes reusable insulated cold boxes and vaccine carriers as well as single-use insulated cartons. Because of the different models available, its versatility and its cost, they are the most used containers for the transport of vaccines.

There are three main types of portable containers: disposable insulated carton boxes, cold boxes and vaccine carriers.

Disposable insulated carton boxes are used by manufacturers to ship their vaccines around the world. They must conform to certain standards. They have a cold life often with a maximum of 4 days.

Three categories of vaccine packaging are used for international air freighting (listed below in decreasing order of bulk):

Class A

packaging is designed to ensure that the temperature of the vaccine does not rise above +8°C for a minimum exposure of 48 hours at an ambient temperature of 43°C.

Class B

packaging is designed to ensure that the temperature of the vaccine does not rise above +30°C for a minimum exposure of 48 hours at an ambient temperature of 43°C. It must also prevent the temperature of the vaccine from dropping below +2°C for a minimum of 48 hours at an ambient temperature of -5°C.

Class C

packaging provides no specific protection against high temperatures. However, it must prevent the temperature of the vaccine from dropping below +2°C for a minimum exposure of 48 hours at an ambient temperature of -5°C.

Based on its dimensions and handling, insulated vaccine containers can be either (1) an individual insulated shipping carton or (2) a pallet shipper. It is recommended that each insulated carton should weigh less than 50kg to ensure ease of handling during transport as they are frequently loaded and offloaded manually. Pallet shippers have a built in wooden or plastic pallet platform to enable handling and transport by forklift or pallet handling equipment. Pallet shippers will generally accommodate higher volumes of vaccines per unit. It is recommended that external dimensions of pallet shippers for vaccines should not exceed standard ISO pallet sizes (US Pallet 1200mm x 1000mm, or Euro Pallet 1200mm x 800mm 276). Pallet shipper height should not exceed 1600mm.

Due to infrastructure and logistics constraints in some locations, it is advised to assess the logistics capacity downstream. In case of limited logistics capacity, it is preferable to ship vaccines using individual insulated cartons.

Cold Boxes

Reusable containers generally used to transport vaccines from one fixed vaccine store to another, and from vaccine stores to health facilities. They have a vaccine storage capacity between 5.0 and 25.0 litres. There are two types of cold boxes:

  • Short range: With a minimum cold life of 48 hours.
  • Long range: With a minimum cold life of 96 hours.

Vaccine Carriers

Used for transporting vaccines where the combined journey time and immunisation activity ranges from a few hours to a whole day. The vaccine storage capacity of vaccine carriers is between 0.1 and 5.0 litres.

When choosing means for transport of vaccines, consider the following factors:

  • The heat and freeze sensitivity of every vaccine being transported. If available, refer to manufacturer indications for further information on temperature sensitivity of vaccines. In any other case refer to WHO How to use passive containers and coolant-packs.
  • The required cold life to keep vaccines at safe temperatures for an entire transport or outreach session. For vaccination outreach sessions the considered time should include travel to and from the vaccination site, allowing the safe management of non-used vaccines.
  • The required capacity based on the volume of vaccines to be transported.

When selecting the appropriate container, the time of transport must be considerably less than the cold life of the container. Unexpected events such as vehicle breakdowns, human error or carelessness, often delay the time of transport. When the duration of the journey exceeds the cold life of the container, it is possible to replace the coolant packs if necessary. The back-up coolant packs can be transported in a separated container or swapped in a stop-by storage facility with compatible coolant packs. It is therefore necessary not to compromise on the number of ice packs which may need to be prepared.

Coolant Packs

Once the decision about the type of container is taken, calculate the number of cold boxes required. Subsequently calculate the number of coolant packs and temperature tracking and alert devices required. Each container holds a specific number of coolant packs.

In regular cold chain management, it is recommended that every cold box or vaccine carrier should have at least two sets of coolant packs, allowing one set of the packs to be cooled, while the other set is being used in the cold box or vaccine carrier. Note that one set of coolant packs is normally provided with each procured cold box or vaccine carrier, so that one additional set at least needs to be ordered.

The type of coolant packs must be selected according to the container and the required temperatures. Ideally, they should be compatible with other coolant packs used in the country.

There are several types of coolant packs:

Water-Filled Coolant Packs

The most commonly used, they are available in a solid rectangular plastic container in different sizes. The most common are: 0.3 litres (in two different sizes: 173x120x26mm and 163x90x34mm), 0.4 litres (163x94x34mm) and 0.6 litres (190x120x34mm). They are used to maintain temperatures in reusable cold boxes or vaccine carriers. WHO currently recommends the use of water-filled coolant packs. Drinking water is safe for such use and is generally available; this makes it the most practical substance for filling coolant packs because both water and ice can effectively control the temperature of the vaccine load, when correctly used.


sealed coolant containers pre-filled with a mixture of water and additives. They are available in flexible plastic bag or in a rectangular plastic container. WHO does not recommend using gel-packs because their thermal properties (freezing point of some gel-packs can be significantly below 0°C) and their lower durability.

Phase-Change Material Packs (PCM-packs)

containers filled with other phase-change materials different from water. They can be designed to change phase at the convenient temperatures range, overcoming the vaccine freezing risk associated with frozen water. However, they are also more expensive and their conditioning process is longer and more complex.

Vaccine manufacturers ship products by air using coolant-packs of various types and sizes containing various fill materials, including water, gel and PCM. It is a common practice to reuse these coolant packs recovered from international shipping containers. WHO discourages this practice as these packs do not necessarily perform in the same way as the water-packs. In addition, they are not designed for repeated use and may not be dimensionally compatible with most of the passive containers used for the in-country supply chain. The recommendation is that, after vaccine arrival, these packs are removed from the receiving vaccine store and recycled or disposed of according to the vaccine manufacturer’s recommendations and/or national waste management policies.

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