Of course, a vaccine is a biological substance. The active ingredients may break down and lose their effectiveness if it becomes too hot or too cold (some vaccine formulations need to be safeguarded from freezing). A dose of vaccine must be produced, distributed to immunization programs, clinics, and health facilities all across the world, and kept fresh until it is required.
The vaccine cold chain, then, is a vast system of cold rooms, freezers, refrigerators, cold boxes, and carriers (like the one pictured above) that maintain vaccines at precisely the appropriate temperature along each stage of the lengthy journey from the production line to the injection.
The majority of vaccines must be stored chilled but not frozen. Imagine transporting glass of chilled water across a desert without having it freeze or heat up. It sounds simple enough in explanation. It goes without saying that in actuality, the cold chain poses a variety of difficulties, particularly when attempting to reach isolated or rural areas or locations with unstable electricity.
When vaccinations are created, the initial products on the market are typically less thermostable (meaning they need to be kept much colder to remain effective).
Manufacturers must spend time adding new ingredients to the formulation of a vaccine in order to make it more thermostable. The new formulations can be stored at lower temperatures after they have been added, but they cannot do so until they have been tested for safety and effectiveness.
For instance, the majority of cold chain vaccines in widespread use are kept between 2 and 8 degrees Celsius, or roughly the same as a standard refrigerator. Some must be stored frozen at minus 20 degrees Celsius, such as Moderna’s COVID-19 candidate and the varicella vaccine for chickenpox.
Several must be stored at extremely low temperatures and require what is known as the “ultra-cold chain”—regular storage at minus 75 degrees Celsius, like Pfizer’s COVID-19 contender (or minus 103 degrees Fahrenheit). Although this greatly heightens the distribution issues, the requirement for severe cold in a cutting-edge vaccination isn’t all that surprising.
Thermostability was always going to be a problem for early distribution in the case of COVID-19 when the world urgently needs a new vaccine.
With either, electricity is a significant obstacle. Power consumption by refrigerators is high. And freezers need even more. In hot climates, ultra-cold refrigerators demand much more power. Adding an unstable electrical system to the mix necessitates the use of generators, which makes the issues worse.
Storage capacity is a problem for all cold chain vaccines, like electricity, but it is made more difficult by ultra-cold formulations—and rendered wholly unprecedented by COVID-19’s requirements.
First, the difficulties with cold-chain storage. Most of the available capacity for the global cold chain is already in use. We’re talking about giving everyone on the earth at least one dosage of the COVID-19 vaccine, if not several. Each of the current front-runners needs two doses; one needs them three weeks apart, and the other needs them four weeks apart.
Therefore, everything must be doubled as soon as possible, including materials, cold chain capacity, logistical planning, and so forth. Additionally, we must ensure that there is sufficient space to accommodate all of these new COVID-19 vaccine doses without displacing the essential vaccines presently utilizing the existing cold chain.
Ultra-cold chain distribution is still conceivable, despite this. Although the Ebola vaccine has been successfully utilized in a number of African nations, the extent of previous outbreaks and that of COVID-19 are virtually incomparably different. The Ebola vaccine also needs to be stored in an ultra-cold chain.
Another significant issue with vaccination delivery is time. It takes months, or more particularly, an average of four to six, to go from the manufacturer to the point of care. Due to the urgent need for a COVID-19 vaccine, distribution will take place over a condensed period of time—hopefully just one month or less. While that might result in an earlier delivery on the one hand, it also implies that governments will have much less time to equip health centers and distribution networks with ultra-cold chain equipment.
Not least of all is the extraordinary amount of cooperation that will be necessary. The physical elements of the cold chain are the coolers, carriers, and cold boxes. However, the cold chain is also a network of interconnected individuals who depend on one another—people passing buckets in a worldwide fire brigade. We’re going to have to collaborate like never before in addition to all the technical difficulties, such as storage requirements.