Why Do Vaccines Need a Cold Chain?

Published by Patrick Famisaran on

Why do vaccines need a cold chain?

In the grand scheme of our COVID-19 battle, our best weapon is vaccines!

With this in mind, it only fits to ensure proper handling and distribution of COVID-19 vaccines. As vaccines are a high-value commodity, protecting them is a must. The best efforts to avoid spoilage and wastage should be in place.

The Vaccine Makeup

vaccine makeup
Photo Credit: www.azcentral.com

The current Moderna and Pfizer vaccine use mRNA technology. To date, the mRNA vaccine is a new type that will be made available for human use. The typical vaccine trains the immune system to respond to a protein emitted by a virus. They usually contain a small amount of inactive virus to train your body to recognize it and fight the virus in the future.`

On the other hand, mRNA suggests that the body, on its own, creates a protein to respond to the virus. Once the vaccine sets in, the body will react to produce the viral proteins. This is essentially worked upon by the messenger RNA used as a template to develop the protein. Hence, if a person gets infected with coronavirus, provided that he/she received the mRNA vaccine, their body’s immune system has cell factories that are ready to produce the viral proteins to fight it off.

If safety is your concern, the mRNA vaccine does not any alter a person’s DNA. There is no concrete scientific basis to conclude that this affects your DNA makeup. The vaccine is much more specific in a way that it only triggers the viruses’ specific protein. This protein is just one of the many components of the viral makeup that invade a human cell. The mRNA degrades in the body very fast. That is why a double dose is needed to achieve the best immune response. 

Temperature Requirements

Back when it was launched, Pfizer claims that its vaccine can be stored to a -70° C. A specialty freezer was required to store up to six months. Recent developments with the Pfizer vaccine suggest that its storage can now be via a normal freezer temperature. This temperature ranges from -25°C to -15°C for up to two weeks. 

Moderna claims a more promising logistical intervention. This temperature ranges from -25° to -15°C for up to two weeks. On the other hand, AstraZeneca can be stored at a higher temperature up to 2-8° C. 

But the common ground for all available COVID-19 vaccines is they need cold storage. Keeping them in cold conditions is imperative. In the whole vaccine deployment scenario, cold storage is the backbone of the vaccine supply chain. And the cold chain is not only limited to transit settings. Even in local vaccination hubs, medical-grade refrigerators are a need. Subnational immunization clinics must invest in freezers to sustain the cold chain. 

The System For Storing Vaccines 

The general term for the system used for vaccine storage is called a cold chain. In principle, it is a supply chain that incorporates cold storage to facilitate vaccine flow. A cold chain system follows the following general procedure:

  1. Ensure vaccines are stored within the recommended temperature parameters
  2. Storage containers and packages should follow regulatory standards
  3. Keep vaccines within standard temperature conditions during immunization sessions

Accordingly, as vaccines flow towards their intended recipients, documentation should be real-time. Data collection, recording, and checking is a significant process throughout the whole chain. Enabling the reporting capacity ensures that the cold chain process has sound monitoring

Environmental Sensitivity

Vaccines are made up of biological ingredients. Such makeup is sensitive to specific environmental conditions. 

  1. Temperature

Temperature sensitivity is prevalent in vaccines. The temperature parameters act as a conditional prerequisite to vaccine quality. The disintegration of vaccine ingredients is often attributed to temperature fluctuations. Protection of vaccines from extreme temperatures is crucial to maintain their potency.

  1. Heat and freezing
vaccines'  sensitivity to temperature
Photo Credit: www.berlinpackaging.com

Because of the temperature prerequisites, vaccines have a specific sensitivity to heat and freezing. Most vaccines dried through freezing quickly lose their potency after reconstitution. Vaccine vials that contain preservatives are also significantly sensitive to changing conditions. As some vaccines are susceptible to freezing, ultra-low temperature storage is a no-no for those categories. 

But because of the higher probability of vaccine wastage, vaccines undergo continuous examination. This examination gauge vaccines’ compatibility with a controlled temperature chain. Such conditions are checked if vaccines can be used in ambient temperatures. The controlled temperature chain approach is beneficial in mass vaccination campaigns.  

  1. Light

Ever wondered why some vaccine vials are not transparent sometimes? Some vaccines come with frosted or opaque vials. This is one way to block light. Exposure to direct sunlight can be detrimental to some vaccines. The makeup of measles and rubella vaccines is sensitive to light. Hence, they come in dark glass vials for added protection from light damage. 

The Cold Chain on the Ground

A mass vaccination program is an enormous task to take. And part and parcel of these extensive campaigns are to delegate vaccine supply at local levels. These are health facilities considered as vaccination hubs. Delegation of the supply aims to reach the last-mile vaccine recipients. This setup is valuable in far-flung communities.

At the health facility level, specific protocols are a must to follow:

  1. Store vaccines in recommended refrigeration equipment
  2. Use a monitoring device to maintain a temperature range
  3. When transporting vaccines, the use of proper cooling containers is advised
  4. During immunization, secure vaccine conditions by fitting a foam pad over the vaccine container

There are also supplementary actions to ensure that vaccine administration has oversight. These are extra monitoring steps to ensure the cold chain is up and running.

  1. Check and record and vaccine temperatures twice daily (it is recommended to in the morning before the start of a session and another at the end of the day)
  2. Proper storing of vaccines and ancillary supplies to containers once finished
  3. Training on preventive maintenance of cold chain equipment

Importance of Monitoring Devices

Because a cold chain requires consistent temperature conditions, the practical way to ensure it is through monitoring. The temperature monitoring device is one of the many monitoring solutions to aid in vaccine deployment. The type of temperature monitoring device comes in many forms.

  1. Vaccine Vial Monitors

These are temperature monitoring devices that are routinely placed in vaccine vials. They have a chemical indicator label that records cumulative heat exposure. The indicator for heat exposure is checking if there is a gradual color change. Through vaccine vial monitors, healthcare workers can distinguish vaccines that are damaged by heat exposure.

  1. Wireless Temperature Loggers

Using temperature loggers in vaccine refrigerators allows better temperature monitoring. Recording the temperature at regular intervals accounts for the condition history of the vaccine. The temperature loggers can also trigger alarms if the temperature drops. In essence, electronic temperature loggers have varying capacities. Reading intervals will often depend on the type of cold storage one has. 

The fast-paced innovation in monitoring solutions can significantly affect the efficiency of a vaccine deployment. As such, measures to improve the system rides on incorporating technological capacities. One example is integrating a central management software to oversee all on the ground cold chain. The Internet of Things enables real-time remote monitoring. Market players provide these monitoring capacities that cover a comprehensive tracking output.

Photo Credit: pharma-mon.com

AKCP Pharma-Mon provides a single user interface called AKCPro server. The interface can geographically drill down mapping, graphing, reports, and alerts. Users can manage all devices on a single platform. Through a central management software like AKCPro server, users can: 

  • track vaccines
  • graph and report data
  • schedule reports for regulatory compliance

Continuous Cold Chain Improvement

With more and more vaccines developed, the cold chain system should respond accordingly. Drugmakers alike will push boundaries to better their vaccine offering. But beyond the actual vaccine is the underlying consequences of taking the jabs to the people. This is where handling, storage, and deployment are crucial. 

There are many requirements for a fool-proof cold chain operation. Companies are investing in logistics innovation to gain a competitive advantage in the industry. Manufacturers are jumping into increasing technological capacities to ‘perfect’ their respective processes. Currently, monitoring specialization has been a significant feature of vaccines already. Logistical linkages from drugmakers to logistic providers are paving the way for cold chain collaboration. The path moving forward is more than just new vaccine discovery. It a holistic combination of distribution efficiency and exemplary parameter management.

Reference Links:

https://www.npr.org/sections/health-shots/2020/11/17/935563377/why-does-pfizers-covid-19-vaccine-need-to-be-kept-colder-than-antarctica

https://www.npr.org/sections/goatsandsoda/2021/02/24/965835993/what-is-a-cold-chain-and-why-do-so-many-vaccines-need-it

https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-019-7786-x

https://www.who.int/immunization/documents/IIP2015_Module2.pdf


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