When Ebola hit the city of Mbandaka in northwest Congo in 2018, health officials had to act fast – the city was connected via regular boat service to the sprawling capital Kinshasa, where the deadly virus could spread out of control. Unlike in previous outbreaks, they had a new weapon – an experimental vaccine that could revolutionise the fight against Ebola – if they could keep the vials between minus 60-80 degrees Celsius in tropical humidity and across rough terrain. As the world embarks on an unprecedented campaign to bring ultra-cold COVID-19 vaccines to billions in remote areas, Democratic Republic of Congo’s experience holds vital lessons in distributing the vaccine and gaining the trust of those receiving it. Congo itself will aim to use the technology and local expertise to get its people vaccinated against COVID-19. The country has recorded over 15,000 cases and 369 deaths from the virus, and faces a second wave of infections. Between 2018-20, health workers inoculated more than 400,000 people in three Ebola outbreaks, lugging vials colder than an Antarctic winter across warm forests and along mud-clogged mountain roads. When cars could not pass, they drove motorbikes. If water was the only way, they used canoes. “These roads are often flooded during the rainy season. A lot of times you have to cross rivers that may not have bridges,” said John Johnson, an immunisation and outbreak response advisor for French medical charity Medecins Sans Frontieres (MSF). It was the largest ever roll-out of an ultra-cold chain vaccine, said a spokesperson for GAVI, an alliance of governments, drug companies and charities that arranges global vaccination campaigns. In Mbandaka, full-scale crisis was averted. The vaccine, and well drilled health protocols, contained the virus. Key to the roll-out was a high-tech thermos that could fit on a motorbike or in a canoe and keep vials cold for a week – essential in Congo where fewer than one in 10 people have access to electricity.