With many children missing out on measles vaccines because of disruption caused by the coronavirus pandemic, fears are growing that there could be an outbreak of the disease in the Democratic Republic of Congo. "In the last two to three months we've not been able to carry out routine measles vaccinations, which is worrying," says Eugénie Ngabo Nzigire, a nurse based in the eastern city of Bukavu. "It takes just one sick child and the whole community is in danger," adds the 57-year-old head of the maternity unit at Skyborne Hospital. The World Health Organization (WHO) has warned that with an estimated 140 million measles vaccinations around the world having been missed due to Covid-19 disruption, countries with fragile healthcare systems, such as DR Congo, could be sitting on a "time bomb" of potential outbreaks. DR Congo reported 440,000 cases in its last measles outbreak, which ended in September. Nearly 8,000 people - mainly children - died from measles between 2018 and 2020 in the country, according to monitoring data from the WHO. Measles is the most infectious preventable disease in the world, much more contagious than Covid-19. It is spread through contact and droplets that can remain in the air for hours. Still a common killer, there are outbreaks currently in Pakistan and Yemen as well as concerns that there could be one in the Tigray region of Ethiopia. "A child can get measles and die wherever they are in the world, but the likelihood of death is much higher for children younger than one and if there are other stresses like malnutrition or vitamin A deficiency, these really increase the risk of death," says Dr Natasha Crowcroft, senior technical advisor for measles and rubella at the WHO. Bukavu is a bustling commercial centre and home to around a million people. It is also where Ms Ngabo Nzigire has dedicated more than three decades of her life to treating children. "I knew I wanted to be a nurse at a very young age, so it's not just a job that I fell into but a vocation to care for people," says the mother of 11. Ms Ngabo Nzigire found her calling unexpectedly when she became very ill and had to be hospitalised at the age of 12. "I remember the nurse treating me was using an old mercury thermometer that you had to shake before taking the temperature," she says. "I was fascinated by it and thought: 'This is what I want to do with my life'." The city is also a distribution hub for vaccines, which arrive from the capital Kinshasa, before being sent out to nearby smaller towns such as Bunyakiri. "It's been four months since we have had measles vaccines available, and we've had other vaccine shortages at the same time," says Marocain Chumac Buroko, a supervising nurse in Bunyakiri.