It had been a year since the Novel Corona Virus (COVID-19) outbreak happened. Scientists had continuously strived to invent a vaccine, and finally, many pharmaceutical companies are coming up with their interventions. With the few of the clinical trials coming to a climax, the Pharma companies and Governments are pondering on the distribution of vaccines to billions of people and their supply chain management which poses as one of the major challenges.
From the time of manufacture till distribution, vaccines must be continuously stored in a limited temperature range, according to the type of vaccine. Different vaccines have different storage conditions like ambient, freeze-sensitive or frozen. Since vaccines are parenteral, optimal temperature and storage are to be taken care of to prevent any leakage and decrease in the efficacy of the vaccine. In order to tackle this challenge, WHO has recommended certain ‘cold chain’ principles to manage the vaccine roll out?
A temperature-controlled supply chain to maintain the quality of the product, in the desired low-temperature, is referred to as a Cold chain. A cold chain is said to be uninterrupted when there is controlled production, storage and distribution in the desired temperature using appropriate equipment and logistics. The cold chain is sometimes referred to as a vaccine supply chain or the immunization supply chain. There are a set of guidelines designed to keep the vaccine in WHO recommended temperature from the point of supply to the point of administration.
To maintain a reliable vaccine cold chain at the peripheral level, we have to
- Store vaccines and diluents within the required temperature range at all sites
- Pack and transport vaccines to and from outreach sites according to recommended procedures
- Keep vaccines and diluents within recommended cold chain conditions during immunization sessions.
Cold chain logistics also referred to as chill chain logistics refers to the transport of temperature-controlled products like bio-pharmaceuticals, foods etc.
Requirements for Vaccine:
The cold chain has three key components: equipment for transport and storage, technical expertise, and effective procedures for management. In order to ensure secure vaccine transport and storage, all three components must be combined.
Proper cold chain management depends on proper temperature monitoring. Minor temperature excursion events (when the vaccine gets stored in temperature range outside the manufacturers’ recommendations), can impact the vaccines’ potency. Thermometers and data loggers should be used to monitor the transit temperature, and thermometers should be used for monitoring temperatures in the storage locations at sites of vaccinations, which must be continuously monitored.
Biologicals are sensitive to Heat, Light and Freezing.
The heat and freezing sensitive vaccines are categorized from Group A, which is more sensitive to heat and freezing to Group F, which are less sensitive to heat and freezing. Analyzing many observational studies, WHO has recommended +2 to +8°C as an optimal temperature for the vaccines which can be stored in normal refrigerators.
Freeze-sensitive vaccines produce adjuvants of aluminum which, when subjected to freezing temperatures, irreversibly lose potency. Freeze-sensitive vaccines require storage at 2 to 8°C and can lose potency even without visible signs that freezing has occurred when exposed to sub-zero temperatures.
Vaccines lose efficacy upon light exposure. To prevent the loss of vaccine efficacy, dark vials are used.
Equipment which are required for Cold Chain:
Different types of equipment are listed under the national cold chain system for transporting of the vaccines and storage of the vaccine. In the national cold chain system, we have three levels of hierarchy, i.e. Primary, Intermediate and Peripheral level. WHO has specified specific prequalification standards to ensure efficient performance of cold chain equipment?
Standard equipment for Cold Chain.
The most reliable power supply should be chosen for the refrigerator, i.e. either electrical, solar or gasoline. The storage capacity should fit for vaccine and water pack storage.
During transportation, cold box is used as an insulated container which can be lined with water packs for storage of vaccines and diluents in required temperature.
Vaccine carriers are easier to carry as they are smaller in size compared to other equipment. Current prequalified vaccine carriers have a cold life with frozen ice packs between 18 to 50 hours at +43 °C and a cool life with cool water packs.
For both cold boxes and vaccine carriers, the ice packs need to be conditioned before packing. Conditioning of ice packs involves completely frozen icepacks to be left at room temperature for a short time (around 30 minutes). This conditioning prevents the vaccines from getting frozen inside the cold box or vaccine carriers.
Water packs are used to line the interior of the cold box/ vaccine carrier. These are flat, leak-proof plastic containers that can be filled with tap water.
It is a soft sponge which fits on top of the water packs inside a vaccine carrier.
India being highly denser population where cold chain involves lots of inventory management, traceable trackers and appropriate storage since biologics are sensitive to minor changes of heat, light and cold. Planning and organization can help us in making the cold chain supply in rolling out the vaccine effectively.
India, being the second most affected country with COVID-19, Government of India is clearing the ground for vaccine rollout and mass immunization, as CDSCO is approving the vaccine use in India. It is pushing its pre-existing cold chain suppliers to augment the requirements based on various players in the market. While Pfizer vaccine recommends a storage temperature of -70°C±10°C during transit and 2-8°C for storage up to five days, Moderna wants the vaccine to be frozen at -20°C during transit. With such restrictions, India’s cold chain logistics industry is gearing up to meet the requirement, but the task looks difficult (though not unachievable being optimistic). Having the vaccine stored and transported at this temperature requires major planning and involves expenditure. The challenge is to get the vaccine transported and distributed to the vulnerable population in remote parts of the country and also to maintain the capability to transport such bulk load without affecting the vaccine. The Indian company vaccines are better when compared for the storage conditions where the manufacturers like Serum and Bharath Biotech have said that their vaccines can be stored in regular refrigerators at 2-8°C. Therefore, in this case the investment will be smaller comparatively.
With the COVID-19 pandemic slump hitting out at all people, together with lockdowns announced in the country, there were significant impacts on all the businesses big and small. But with this phase, the cold chain industry is going to have significant growth and is sure to get revamped for good, and we hope so.