What is the Cold Chain?

“This porridge is too hot!  This porridge is too cold.  Ahhh, this porridge is just right.” 

These few lines should send you on a trip down memory lane all the way to the cabin with the Three Bears.  Now replace “porridge” with “vaccine.”  You’ll find it’s not so easy to be Goldilocks.  It’s hard to figure out which vaccines are “just right” enough to inject people with.  Stored in extreme heat or extreme cold, vaccines can go bad.  Vaccines need to be at the right temperature so that they can protect people from disease. 

The cold chain is the sequence of events required to transport temperature-sensitive products through refrigerated units.  Products typically include vaccines and pharmaceutical drugs.  In fact, based on a recent study conducted by PharmaCommerce, seven of the ten top global pharmaceutical products in 2014 will require cold-chain handling.[1] The general chain is made up of five locations: manufacturing headquarters, international airport, regional ministry of health, local hospitals/clinics, and community centers.  To get from one step to the next, products are transported by plane, truck, motorcycle, or bicycle.  In rural areas where roads are not developed, they are transported by foot. 

It seems simple enough, but the task of maintaining temperature has puzzled the world for centuries.  The practice of using refrigeration dates back to 1797 when British fishermen used ice to preserve stock piles.  Shortly after in the 1870s, frozen meat was moved across oceans.  The 1950s brought companies that specifically wanted to transport pharmaceutical and medical supplies to the world.  By the 1990s, the world was literally shrinking thanks to the Internet, but there were still big distances for products to travel physically from origin to destination. 

Even today there are big differences from country to country, town to town, or city to city in terms of how the cold chain is carried out.  In underdeveloped areas where electricity is unreliable, vaccines go bad fast.  Think back to when you lose power during a thunder storm; when the storm subsides, you have to throw away all the food in your refrigerator.  The worst part is that often the vaccines are not thrown out.  Where electricity is totally unavailable, more compact ice-lined refrigerators are used to store products.  A major problem exists in using the different refrigeration equipment at every stage of the cold chain.  Health workers need to know how to monitor the vaccine temperature and what to do if something goes wrong.  Communication is key to a smooth operation. 

Making sure the cold chain is tightly regulated will be crucial to rolling out vaccines and drugs in the future.  From both an economic perspective and a human perspective, it is critical to keep improving the cold chain. 

---

[1] http://www.fiercebiotech.com/press-releases/todays-global-biopharma-cold-chain-market-5-1-billion-growing-6-6-billion-2011