Vaccine refrigerators are essential elements in the cold chain.

“The potency of vaccines depends on maintaining the cold chain—that is, a prescribed temperature range during distribution from manufacture to use.” Can’t put it much clearer than that, a statement from a 1993 paper in the British Medical Journal. The paper measured compliance with codes—particularly in reference to maintaining the cold chain for vaccines.  Although things may have changed in the intervening years, the 1993 study found pretty low compliance with such rules as placing a maximum-minimum thermometer in the center of the vaccine refrigerators and ensuring that the electrical supply to the vaccine refrigerator can’t be interrupted.