The world's largest yellow fever vaccination effort has.come to the urban sprawl that is the Democratic Republic of the Congo's (DRC) capital, Kinshasa. In August, authorities hoped to vaccinate those most at risk among the 10.5 million people living there, and Doctors Without Borders (MSF) has mobilised massive resources in support. Late last year a yellow fever outbreak struck the Angolan capital, Luanda, and soon cases were also reported in Kinshasa, leading to a total of over 400 deaths. In Kinshasa, MSF teams were responsible for vaccinating 760 000 people — 10% of the city's 7.5 million vaccination target — in three health zones. In partnership with the DRC's ministry of health, MSF undertook this largescale vaccination campaign during August.