An effective cold chain is fundamental to the success of vaccination programmes. Millions of dollars' worth of vaccines are stored throughout developing countries in the cold chain at any one time; this amount will increase year on year as countries incorporate newer often more expensive, vaccines into their immunization programmes. Vaccines stored outside 2-8 ^o C lose efficacy and may fail to protect their target population.The result is wasted vaccine and lost lives.^

Outside of national vaccine stores the cold chain can be fragile, relying on intermittent electricity supplies and on equipment which may be inefficient or simply not designed to deliver the performance needed in harsh conditions. The International Energy Agency (IEA) estimates that by 2020, developing countries will need to double their electrical power output. The IEA predicts that power outages in developing countries will become even more prevalent in the coming years as National Grids have insufficient capacity to deal with the ever increasing demands put on them

How should we plan to address the issues threatening the integrity of the cold chain? Do we design equipment that will reliably deliver the performance needed on reduced amounts of electricity (say from 8 hours down to 5 or 6 hours)? Do we focus on producing equipment which delivers increased holdover times of days rather than hours?

Simply using generators as an alternative means of producing power has its own problems such as the high cost of fuel, the cost of transporting fuel to remote areas where it is needed, maintenance of generator performance in hot dusty conditions theft of fuel, and increased carbon emissions. Likewise, whilst solar powered fridges may be the solution in some locations, use of solar power to run appliances may not necessarily be the simple solution it seems. Solar fridges are more expensive to produce and buy than those run by electricity, and solar panels continue to be attractive to thieves, requiring expensive replacement.

We cannot afford to ignore issues affecting the integrity of the cold chain. A failure to address these issues now will result in unsuitable equipment being purchased for use with the ensuing failure of the cold chain, wastage of vaccine and loss of lives.

Questions for discussion:

 Is the future integrity of the cold chain under threat?

Should the requirement for access to mains power be reduced say from 8 hours down to 5 or 6 hours?

Should holdover times of cold chain equipment be increased, and if so, to what length of time as a minimum?

Under what circumstances can solar refrigeration provide the best solution?