Solar fridges and powdered vaccines: How to get a COVID-19 vaccine to the developing world

UNICEF is building a global network of fridges and cold rooms—the cold chain—to make sure a vaccine stays effective as it’s transported to rural communities off the grid.

Solar fridges and powdered vaccines: How to get a COVID-19 vaccine to the developing world
Elisabeth Abraham Loro, a nurse and vaccinator, collects vaccines from a cold box at a healthcare center in South Sudan. [Photo: Charles Obel/© UNICEF]

When a COVID-19 vaccine is approved for use, one of the next major challenges will be logistical: How do you distribute billions of doses around the planet, including to remote corners of the world that lack reliable electricity, when the vaccine has to stay refrigerated to be effective?


As part of the preparation, UNICEF is mapping out a network of refrigerators and cold storage rooms across the developing world—and helping put new equipment in place, including tens of thousands of refrigerators that run on solar power. Other groups, like the International Rescue Committee (IRC), are focusing on preparing healthcare workers to administer the vaccine.

“For a situation of this size, where so many countries need to launch a vaccine at the same time for so many people, it’s a huge undertaking,” says Dr. Mesfin Teklu Tessema, who leads the health unit for the IRC. “And unless everyone is protected, no one is safe.”

UNICEF is the sole provider of cold-chain equipment to Afghanistan, such as this refrigerator in use by the country’s Ministry of Public Health. [Photo: Omid Fazel/©UNICEF]
UNICEF, the U.N. agency that provides humanitarian aid to children globally, started planning for the challenge early in the pandemic. “When the initial signals of the emergency started, we already started mobilizing and preparing, because we knew that we would be playing a role of some sort,” says Michelle Seidel, a cold-chain specialist at UNICEF. Because the organization handles routine childhood immunizations in places like sub-Saharan Africa, it already has a distribution network in place for vaccines, and it’s spent years working to improve it—including the challenge of how to keep vaccines cold.

Mamadou Kassé, left, a mobile vaccinator from the Sofara Community Health Center in Mali, travels by donkey cart for miles to reach the remote Kankelena village with vaccines. [Photo: Seyba Keïta/©UNICEF]
The “cold chain” involves maintaining low temperatures at each step of the journey. Doses of the vaccine will travel on flights to a country, where the government will typically have them delivered to a national cold storage facility. Next, the vaccines will go on to other distribution centers and clinics.

In remote areas, the healthcare worker in charge of vaccinations may have to carry the vaccines on the back of a motorbike or on a bicycle, horse, or boat. (The first rollout of vaccines, which will prioritize healthcare workers, should be easier to deliver than later stages in the most remote regions.) At each stage, the vaccines have to be monitored to make sure they’re not getting too warm.

A vaccine cold box in South Sudan [Photo: Charles Obel/© UNICEF]
While the vaccines are being moved, they’re often kept in insulated boxes with ice and sensors. While they’re in storage, one piece of the solution is refrigeration tech that runs on solar power, which can fill a gap in areas that don’t have access to reliable electricity. In South Sudan, the least-electrified country in the world, where only around 28% of the population is connected to the grid and where it’s common for temperatures to surge above 100 degrees Fahrenheit, UNICEF has installed solar fridges in more than 700 health facilities. Thousands of solar fridges have also been installed in other low-income countries; by the end of the year, the agency expects to have 65,000 solar fridges in place around the world.


A solar-powered refrigerator in South Sudan [Photo: Charles Obel/© UNICEF]
The tech keeps evolving. Early solar fridges had batteries to store electricity from solar panels, but that didn’t work well. “Batteries were quite a weak link—they were the main cause of failure, and we often found that they weren’t replaced when they broke down,” Seidel says. The current “direct drive” version solves the problem by storing power directly inside the fridge.

Larger cold storage rooms that run on solar power are also expected to soon be approved for use by the World Health Organization, though they aren’t in place yet. UNICEF also works to help clinics install more conventional refrigerators and cold storage rooms in some areas. The agency is currently working with countries to map out available refrigeration in detail—from hospitals to private labs and other sites—and plan where new infrastructure needs to be added.

Solar panels are installed atop the primary healthcare center in Gurei, a township on the outskirts of Juba, the capital city of South Sudan. [Photo: Charles Obel/© UNICEF]
Some clinics and distribution centers use other recently developed technology from companies such as Sure Chill, which uses a unique design with ice to keep vaccines cool for days, or even weeks, without a source of power. “We’ve seen a huge increase in activity, including an order in the last month for 9,000 vaccine refrigerators from one country,” says CEO Nigel Saunders. “Every country is now beginning to rapidly ensure it has a cold chain to cope with the demand. As things stand today, few countries (if any!) have the ability to cope with the demand and rollout of a COVID vaccine using existing cold chains. Countries need to quickly rethink and develop a solution that reaches the masses quickly.”

The existing network for storing childhood vaccines is critical, though success will also depend on which vaccines are approved. Some vaccines, like one in development from Johnson & Johnson, can be kept at 2 to 8 degrees Celsius. Others, like Pfizer’s promising mRNA vaccine, have to stay at ultralow temperatures of minus 70 or minus 80 degrees Celsius.

“That kind of cold chain currently doesn’t exist anywhere in the places where we work,” says the IRC’s Tessema. “So it’s going to be a huge challenge to deliver this vaccine. In many of these countries, the infrastructure has to be built up from the bottom, both at the national level or regional distribution, as well as the local distribution chain.” Still, it’s also possible that a vaccine that doesn’t require refrigeration will eventually succeed. Pfizer is working on a powdered version of its vaccine, which will utilize standard refrigeration.

One of the biggest challenges now, says UNICEF’s Seidel, is trying to plan infrastructure without knowing which vaccine or vaccines will ultimately be approved and how quickly they’ll be manufactured. “At the moment, we’re working with a number of various vaccine candidates, and we’re very unsure about the quantities that are coming from the various candidates and what temperature ranges they can be stored at, and this makes planning exceptionally difficult from a supply chain and cold-chain point of view,” she says. “Working under that type of uncertainty is quite challenging. So we have to develop scenarios, and plan under multiple scenarios, in order to be prepared.”

About the author

Adele Peters is a staff writer at Fast Company who focuses on solutions to some of the world's largest problems, from climate change to homelessness. Previously, she worked with GOOD, BioLite, and the Sustainable Products and Solutions program at UC Berkeley, and contributed to the second edition of the bestselling book "Worldchanging: A User's Guide for the 21st Century."