August 11, 2021
min read

Note: The vaccine cold chain. Adapted from the New Zealand Ministry of Health.

The importance of the vaccine cold chain in battling Covid-19

Covid-19 vaccinations started to roll out beginning of December with the United Kingdom being the first country administering a Covid-19 vaccine after national regulators had given emergency authorization, followed by countries such as the United States of America and Canada. Other countries are about to follow with decisions on emergency use authorizations as part of their unprecedented efforts to end the Covid-19 pandemic.

The distribution of billions of doses to ensure enough people are vaccinated to stop the spread of the coronavirus poses significant challenges to the vaccine supply chain. Not only the vast number of doses but also the very low temperatures, at which the most promising vaccines to date need to be stored, challenge the vaccine cold chain. Moderna’s vaccine, for instance, needs to be kept at –20 °C while Pfizer’s vaccine even needs to be kept at –70 °C. Distributing the Covid-19 vaccines will, therefore, need a refrigeration system that ensures the correct storage of these vaccines at each stage of the supply chain.

Vaccine storage temperatures

Not only Covid-19 vaccines but vaccines in general, are very sensitive to temperature and can quickly spoil if they are not kept at correct temperatures. Overheated vaccines, for instance, promote the growth of pathogens, while freezing vaccines can reduce their efficacy.

Most vaccines need to be refrigerated at temperatures between +2 °C and +8 °C to not lose their potency and stability. Some vaccines, such as these against MMRV, Varicella or Zoster, need to be frozen within the range between -15 °C and -50 °C. The vaccine against Ebola even needs to be stored at very low temperatures between -60 °C and -80 °C.

Improper vaccine handling and storage, therefore, can result in costly and delayed revaccinations and vaccine wastage. The World Health Organization (WHO) estimated that up to 50% of the vaccines are wasted on a global scale each year. As vaccines are expensive, even small vaccine providers often store vaccines worth several thousands of dollars, and breaches of the cold chain can become costly for the involved parties.

Vaccine manufacturers, distributors as well as providers, such as pharmacies, general practices, public health units, travel clinics or hospitals, therefore, need to avoid any cold chain failures that might thermally compromise the vaccine and in the end its spoilage.

Standards for vaccine storage and transportation

Immunization providers need to comply with national standards for the storage and transportation of vaccines. The New Zealand Ministry of Health requests vaccine distributors and providers to transport and store all vaccines at the correct temperatures to ensure the continuation of the cold chain.

New Zealand vaccine providers are required to use pharmaceutical refrigerators to store vaccines. In addition, they need to implement two forms of temperature measurements to ensure correct temperatures. First, vaccine providers need to record minimum and maximum refrigerator temperatures daily, with the help of minimum/maximum thermometers for example. Second, they must record the cold storage unit’s temperature continuously, at least every 10 minutes (a 5-minute interval is recommended) with the help of temperature monitoring sensors or data loggers. The American Centers for Disease Control and Prevention (CDC) also recommends all players along the cold chain to develop and implement Standard Operating Procedures (SOPs) to always ensure proper vaccine storage and handling.

The Vaccine Cold Chain

The vaccine cold chain encompasses all processes along the lifecycle of the vaccine ought to maintain the vaccine at the required temperatures, from the cold storage unit at the manufacturing facility through the transport and distribution process to the administration of the vaccine to the individual patient.

As the refrigerated and frozen vaccines need to be kept at their optimal holding temperature throughout the whole cold chain, they are transported in refrigerated trucks, cold boxes, or vaccine carriers to ensure their correct temperature during transport. However, transporting vaccines increases the risk of temperature deviances due to the increased number of handling points or improper cooling materials, for instance. What is more, manual temperature monitoring and data entries, as well as paper-based reporting, can lead to significant data gaps or measuring errors, undermining the traceability of the vaccine cold chain.

The necessity of real-time temperature monitoring

As vaccines are temperature-sensitive, close temperature monitoring along the whole cold chain is essential to preserve their potency. While minimum/maximum thermometers only show the coldest and warmest temperature reached in a monitored cold storage unit, Internet of Things (IoT) enabled temperature monitoring devices monitor the vaccine temperature more closely. These smart sensors record temperatures of the cold storage unit continuously at pre-set intervals. Each cold storage unit should be equipped with one temperature monitoring device to show temperature deviances precisely and reliably.

Real-time temperature monitoring with the help of wireless IoT sensors ensures traceability in form of seamless temperature control of vaccines during the storage in freezers and refrigerators as well as during transport. Directly positioned in the cold storage or transportation unit, the wireless temperature sensors ensure 24/7 temperature monitoring and set off immediate alarms if the temperature passes recommended temperature thresholds.

Remote monitoring can, therefore, replace manual monitoring, avoiding unnecessary opening of cold storage doors that might compromise vaccine temperature. Real-time monitoring even allows for predicting cold storage failures, proactively eliminating cold chain breaches.

As opposed to digital data loggers that usually need to be connected to a computer to download the recorded data, IoT monitoring devices can store the collected data automatically in a cloud, allowing for real-time visibility and access from any location.

IoT monitoring devices run on batteries, ensuring temperature readings even during a power outage or during transport. The device logs the data during the power outage or transport until it can transmit the data to the cloud again,

The 5 advantages of IoT temperature monitoring devices in the vaccine cold chain

The use of IoT-enabled temperature monitoring devices in the vaccine cold chain facilitates cold chain management significantly. In sum, smart temperature monitoring devices offer the following 5 major advantages:

  • Real-time temperature monitoring
  • Automatic alerts
  • 24/7 visibility
  • Predictive analytics
  • Audit-ready reports

Monitoring vaccine temperatures with the help of IoT temperature monitoring devices is an effective way to ensure continuous vaccine safety along the cold chain and, therefore, reduces the potential of costly revaccinations and stock loss.

This becomes particularly important for the distribution of the different vaccines against Covid-19 as part of the current global efforts to end the pandemic. iMonitor provides real-time vaccine temperature monitoring solutions for a range of pharmaceutical distributors and pharmacies in New Zealand.

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