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COVID-19 community stories

How we keep COVID-19 vaccines cold

Maintaining the right temperature is vital when flying COVID-19 vaccines across the world.

Transporting billions of COVID-19 vaccines across the world is an unprecedented logistical challenge. What makes it even harder is the need to store vaccines at the correct temperature. Most vaccines need to stay cool, with some requiring extremely low temperatures in order to remain effective.

As experts in pharmaceutical shipments, we have the know-how, specialist equipment and procedures to be able to deliver these temperature-sensitive shipments safely. Here’s how we do it.

1. Prepping vaccines for shipment and

loading temperature-sensitive cargo

When vaccines leave the factory, they are carefully packed to protect them from ambient temperatures outside. They are then loaded into refrigerated trucks and driven to the airport.


For shipments that need to be kept cold, we use cooltainers, which are purpose-built with thick insulated walls (like a domestic fridge) to help keep sensitive cargo within the desired temperature range.

2. Choosing the right type of cooltainer

Cooltainers can be divided into two camps – active and passive.


An active cooltainer has a thermostat and technology that allows them to regulate temperatures. They tend to be powered by batteries that need to be charged between flights.


The operating range of active cooltainers is between -10°C to 15°C, which is ideal for the bulk of pharmaceutical shipments, but they cannot reach the extremely low temperatures required for some of the vaccines. For these cases we use passive cooltainers.

3. Passive cooltainers for extra-cold shipments

A passive cooltainer is essentially a large cool box that uses special frozen gel packs to retain temperatures below 0°C for longer. Alternatively, they're filled with dry ice, which has a freezing point of -78.5°C.


For vaccines that require a temperature of -70°C, such as the Pfizer vaccine, dry ice is the ideal option.

4. Monitoring the shipments in transit

During the shipment process, our highly-trained team are constantly monitoring the temperatures. This includes checking there is sufficient dry ice, or charging batteries on the active cooltainers.


Most cooltainers also have data-logging equipment to record information during the journey, so our people can monitor temperatures and alert teams on the ground if any action is required.

5. Cold storage at the cargo terminal

Speed is of the essence when shipments arrive at the cargo terminal, with vaccines being given top priority to minimise their exposure to ambient temperatures. If vaccines need to be stored for a period of time before travelling on to their final destination, they are transferred to special cold room facilities.

The Cathay Pacific Cargo Terminal in Hong Kong has a large cold room, capable of maintaining temperatures from 15°C to below freezing, and will soon have an increased vaccine capacity from seven million doses to around 8.6 million.

6. Keeping shipments cool on the tarmac

When it comes to moving cooltainers to the aircraft, we use thermal dollies to transport them.

Dollies are temperature-controlled wheeled vehicles that can be towed. In essence, they are large mobile cooltainers that can hold two cooltainers at a time to help maintain correct temperatures.

Finally, the cooltainers are loaded onto our 20-strong Boeing 747 freighter fleet, or in the cargo hold of our passenger aircraft to reach their final destination.