Known as a “cooler” in the US, a “chilly bin” in New Zealand and an “esky” in Australia, the cool box is an everyday item of summer picnics everywhere. It was invented in 1951 by American Richard Laramy of Illinois who successfully patented the idea of a “portable ice chest”. They became especially popular as a domestic item in the warmer parts of the US during summer where the concept of refrigeration and the constant supply of ice for cooling drinks had first taken hold.
However, versions of the cool box have also proved invaluable in transporting vaccines over long distances in hot countries where refrigeration and electricity is limited. Many vaccines are particularly vulnerable to higher temperatures because they are composed of biological molecules that can be destroyed or “denatured” when kept in warm conditions for any length of time.
Mass immunisation with effective vaccines has been an incredibly successful medical strategy globally. It led to the eradication of smallpox, a 74 per cent reduction in childhood deaths from measles over the past decade and the near eradication of polio. Yet one in five children worldwide are still not fully protected with even the most basic vaccines, often because of the logistical difficulty of transporting the medicines over difficult terrain without refrigeration.
The design of ice boxes for medical purposes, however, is getting better, enabling doctors to reach some of the most difficult places where vaccines are needed. Some of the latest ice boxes, for instance, can maintain a temperature below 4 degrees Celsius for a week and store up to 3,000 doses of vaccine. Such relatively simple technology, intended for field work by vaccination teams, provide an alternative to regional or peripheral refrigeration stores and provide some protection against any local power failures that can quickly destroy a precious stock of delicate medicine.