Successful public health programs rely on the availability of high-quality vaccines, which must be continuously cooled to remain effective. Fail-safe refrigeration within a specified range of temperature, from point-of-manufacture to point-of-use, is critical to the effectiveness of any vaccination program. Fail-safe refrigeration is also vital for maintaining the shelf of some medicines e.g. the liquid forms of antibiotics.
The term “cold chain” refers to a network of fridges, freezers and cold boxes that is organised and maintained by teams of people throughout the world. This network ensures, as much as possible, that vaccines are kept at the proper temperature as they are distributed from the manufacturer to the locations where they are administered.
The recommended equipment for storage (cold rooms, refrigerators, freezers) and transport (cold boxes, vaccine carriers) has to comply with a set of performance standards defined by WHO.
Maintaining the required vaccine cold chain is problematic in many regions of the world that are either off the electrical grid or the electrical supply is unstable. Weak links in the current cold chain in such places results in large quantities of spoiled vaccines each year.
Kerosene Vaccine Coolers
Currently, in parts of the world where there is no reliable electrical supply, vaccines are most often stored in kerosene refrigerators.
Kerosene refrigerators consume approximately .8 to 1 litre of kerosene daily. They emit the unsavory odor of burning kerosene, they occasionally catch on fire, they need to be regularly fueled up with permanent operating costs, and they are often not reliable for maintaining the required temperature.
Furthermore, they are environmentally harmful as the burning of kerosene contributes to global warming. There are approximately 100,000 kerosene refrigerators in use today around the world for vaccine cooling purposes. It is estimated that one kerosene refrigerator annually emits between 732.9 to 916.1 kg of CO2 into the atmosphere. Correspondingly, 100,000 kerosene refrigerators will emit approximately between 73 to 91 million kilograms of CO2 each year.
The current fleet of kerosene refrigerators are aging. SolarChill may prove to be the viable alternative for the orderly replacement of many of these units.
Solar Vaccine Coolers
Vaccine refrigerators that can be powered by a variety of energy sources can alleviate the problem of non-existing or insufficient electrical supply. Solar and multi-sourced vaccine coolers can also be of great benefit under emergency circumstances such as natural disasters or war conditions. Multi-sources of energy include solar, wind, bio-fuel and other forms of generation, as well as the electrical grid.
Solar Vaccine Coolers are already in use in parts of the world that lack electricity. These units have proven to be more reliable than their kerosene counterparts.
However, there are only approximately 6,000 solar vaccine coolers around the world today. Two factors that inhibit the wide scale uptake of current generation of solar coolers in developing countries: the reliance on batteries, and the relative high costs.
The problem with batteries is that they often break down, they are expensive to replace, they are heavy, and they are toxic. Batteries need replacement on the average every 3 to 5 to five years. They also require maintenance and be routinely refilled with distilled water.
The cost of present day solar coolers is in the $3500 to $4500 range. In comparison, the cost of the SolarChill package, cooler and solar panels combined, is projected to come in around $1500.
The challenge therefore is to bypass the reliance on batteries, to provide the greatest versatility in terms of power supply of any product on the global market and to keep the price affordable.