Supplies and Logistics

Cold Chain

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© UNICEF/NYHQ2011-2454/Sokol
Carrying a 'cold box' filled with polio vaccines, vaccinator Nyaluak Tebuom, 14, passes other travellers on a dirt road as he journeys to Pakur Village, in Unity State. Nyaluak must walk more than 10 kilometres on the road, which is laden with anti-tank mines, to administer the vaccines to the village’s children.

Cold-chain: the last child, the last mile

Ensuring vaccines reach every child, wherever they live, is a complex process. A number of factors have to converge to make this a reality. Not only do vaccines have to arrive in time to be distributed where they are needed, all vaccines must be continuously stored at the appropriate temperature from the time they are manufactured up until the moment of use.

High temperatures or fall in temperature below zero for freeze sensitive vaccines can cause vaccines to lose their potency – that is, their ability to provide protection against diseases. Once a vaccine loses its potency it cannot be regained or restored. In retrospect, Heat exposure beyond the recommended temperature may also cause an immunological reaction if the vaccine is used.

The system used for keeping and distributing vaccines in potent condition is called the 'cold chain'. Vaccines are always sent directly from the supplier to the country of intended use by plane as refrigerated cargo. On arrival, vaccines are moved to cold and freezer rooms and from there, distributed to Sub-national stores by refrigerated vehicle. Cold boxes and vaccine carriers are used to distribute vaccine right down to the village level. During an immunization campaign or outreach service, community health workers are provided with smaller easy-to-carry vaccine carriers that can be transported via car, motorcycle, bicycle, donkey, camel or on foot to children in even the most hard to reach places.

UNICEF procured for more than USD 30 million worth of cold chain equipment in 2012. UNICEF Supply Division works closely with UNICEF program colleagues, partners and governments to ensure the cold chain is working effectively and efficiently.

The recommended storage and transport equipment (cold/freezer rooms, refrigerators, freezers, cold boxes, vaccine carriers and transport needs to comply with a set of performance standards defined by WHO . Stock management procedures have been established so that vaccines are not stored longer than necessary at the central, regional and district levels of the cold chain. Different vaccines require different storage conditions, and what can be safe for one type of vaccine, may be inappropriate for another. See the full acceptable storage conditions here.

UNICEF Supply Division has developed a Cold Chain Country Support Package to provide procurement guidance and technical support to countries and partners planning to strengthen cold chain systems.

 


 

 

Cold Chain Weight and Volume Calculator

The Cold Chain Weight & Volume Calculator is a practical tool for calculating the space required for in-country deliveries and cold chain storage.

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