Picture: Pixabay
Picture: Pixabay

Covid-19 vaccines must be stored under these conditions or risk being damaged

By Rudolph Nkgadima Time of article published Feb 3, 2021

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Cape Town – WITH the arrival of 1 million Covid-19 vaccine doses in South Africa on Monday, the country is now a step closer to rolling out the vaccine to its front-line workers.

To ensure a successful distribution and delivery of the vaccine, to all the provinces in the country, the vaccine needs to be transported and stored under specific conditions.

“It is extremely important to maintain temperature control in the transportation, handling and storage of any vaccine,” explains Eckart Zollner from Ikhaya Automation Systems, a Pietermaritzburg-based remote temperature monitoring specialist company.

“The result of unmaintained temperature throughout the vaccine cold chain is highly dependent on the vaccine type. Vaccines are biological substances that may lose their effectiveness quickly or become potentially dangerous if they become too hot or too cold at any time, especially during transport and storage,” Zollner said.

It refers to the process of distribution and storage at cold temperatures to keep vaccines stable.

Established cold chain

Most pharmaceutical distribution companies are able to store and move the vaccines.

According to reports the country’s two biggest pharmacy chains Clicks Group and Dis-Chem Pharmacies plan to offer Covid-19 shots at their stores and provide storage and distribution facilities in the vaccine roll-out programme once the government provides more details.

Bespoke ultra-cold containers

Thermal shippers are maintained at -70°C using dry-ice. GPS enabled temperature trackers help monitor vaccine stability.

These insulated medical Thermo boxes operate through the use of reusable frozen gel packs. These boxes will maintain the required temperature for up to 24 hours. Vaccines inside the Thermo box have to be either used or returned to medical refrigerators within 24 hours.

Transporting the vaccine

As vaccines travel from urban cities to rural and remote areas correct cold chain temperatures need to be maintained at all times.

The AstraZeneca vaccines do not require specialised ultra-cold freezers or vast quantities of dry ice, making it easier to supply

If the correct cold chain temperatures are maintained, all three vaccines will have a shelf life of about six months.

According to Zollner, logistics, transport and storage businesses should be investing in automatic real-time control systems that measure and record every few minutes and transmit the data regularly.

“As recommended by the World Health Organisation (WHO), the entire chain would benefit from inclusion of temperature monitoring devices such as data loggers, threshold indicators and vaccine vial monitors (VVMs) on all vaccine touch points. These technologies are capable of sending immediate alerts upon any form of temperature excursion and can provide a log of temperature readings,” he said.

Vaccine storage temperatures

AstraZeneca: 2 to 8ºC.

Moderna: -20ºC to minus 5ºC.

Pfizer/BioNtech: -70 to -10ºC.

Maximum duration in and out of storage


The vaccine can last for at least 6 months kept at 2ºC to 8°C .

It can be administered in existing health-care settings — stored, transported and handled at normal refrigerated conditions.

After first opening the vial, at room temperature the AstraZeneca vaccine should be used within 6 hours.


The vaccine can last for at least up to 6 months kept at -70°C.

The Pfizer vaccine comes with thermal shippers that stabilise ultra cold temperatures with dry ice.

After 10 days, the shippers need to be refilled with 23kg of dry ice and then refilled again every 5 days.

After 15 additional days, the Pfizer doses need to be removed from the thermal shippers and either stored short term in medical refrigerators or long term in ultra-low freezers.

After dilution, the Pfizer vaccine should be used immediately and within 6 hours.


The vaccine can last up to 6 months kept at -20°C.

For shipping and long-term storage, Moderna expects the vaccine will be stable in most home or medical freezer temperatures.

Moderna vaccine can be refrigerated for a month within the six-month shelf life.

Once the first dose has been taken, the other doses in the vial should be administered within 6 hours.

Storage at vaccination facilities

The Pfizer vaccine requires specialist ultra-cold freezers and storage.

Moderna and AstraZeneca vaccines can be stored in existing medical freezers.

Zollner said: “Effectiveness cannot be guaranteed for vaccines unless they have been stored at the correct temperature from production to the end-user.”

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