This video is a quick introduction to the cold chain—the uninterrupted link from manufacture to administration that keeps vaccines within a narrow temperature range. The problem outlined in the video is that many of the world’s poorest regions do not have the infrastructure to support vaccine refrigerators at every administration site. The video reports that 30 to 50 percent of the children in these countries without infrastructure receive spoiled vaccine. They point to advanced technologies that may eventually result in thermo-stable formulations that don’t need to be constantly kept cool.