A British hospital network is using blockchain technology to track COVID-19 vaccines

A U.K. hospital network has become one of the first worldwide to use a digital ledger technology, similar to the one that underpins several cryptocurrencies, to track the handling of COVID-19 vaccines.

South Warwickshire NHS Foundation Trust, which is part of the government-run National Health Service and administers four hospitals in central England, has begun using the Hedera Hashgraph system to keep track of whether COVID-19 vaccines are being stored at the correct temperatures, Hedera and Everyware, a U.K. software company that is overseeing the project, said Tuesday.

The hospitals include one in Stratford-upon-Avon, the city best known for being Shakespeare’s birthplace and hometown.

In recent weeks a number of tech companies, including IBM, have proposed using blockchain technology, which is a kind of digital ledger that is maintained across a network, rather than stored in one central location, as a way to ensure data on coronavirus vaccine doses is both secure and can be shared easily across organizations that normally use different record-keeping systems. But South Warwickshire’s use of Hedera is thought to be one of the first implementations of this kind of technology for tracking vaccine handling.

Accurately tracking the status and handling of vaccine doses is particularly crucial because the inoculations produced by Pfizer and Moderna must be kept at ultralow temperatures of –70 degrees Celsius (–94 Fahrenheit) until close to the time they are to be used, while the vaccine from AstraZeneca must be kept at normal refrigerator temperatures.

Everyware has already worked with South Warwickshire to track the handling of some chemotherapy drugs, blood supplies, and ophthalmology drops that must also be kept at specific temperatures. It has done so by using Internet-connected sensors that it places in a room or within a hospital refrigerator. Doing so has helped the hospital reduce cases in which medicines had to be discarded because staff were uncertain they had been maintained at the correct temperature, Tom Screen, Everyware’s technical director, told Fortune.

“This way, we can verify the data hasn’t changed from start to finish; that the data has been in our custody and the data is valid. And we can say the analytics that you might want to run on top of this is valid,” he said.

Everyware chose the Hedera Hashgraph blockchain because it offers a very low fixed cost per piece of information added to the blockchain—just 1/100th of a U.S. penny—and can quickly handle millions of data entries, Screen said.

In contrast, many cryptocurrency-based blockchains can handle no more than one or two dozen transactions per second, and are many times more expensive, with a cost that varies as the value of the related cryptocurrency moves up and down owing to market forces.

Hedera’s Hashgraph digital ledger does not use the same kind of blockchain that Bitcoin and Ethereum do. Instead it uses a different kind of mathematical system, called a directed acyclic graph (or DAG). One benefit of this system is that it does not require nodes in the network that stores the digital ledger to solve complex mathematical puzzles as in cryptocurrency-based blockchains, which is why Hedera can offer such a low cost per piece of information added to the ledger and can process transactions so quickly.

Hedera is based in Dallas, but the platform is governed by a council that includes a number of large multinational corporations, many of which also use the network for their own record-keeping. This includes Avery Dennison, Boeing, Deutsche Telekom, Dentons, DLA Piper, FIS (Worldpay), Google, IBM, LG Electronics, Magalu, Nomura, Swirlds, Tata Communications, University College London (UCL), Wipro, and Zain Group.