In the clear An experimental vaccine administered to nearly 6 000 people in Guinea who were in close contact with Ebola patients has been found to be 100% effective. The trial was led by the WHO in conjunction with Guinea’s Ministry of Health, Médecins sans Frontieres and the Norwegian Institute of Public Health, in collaboration with other international partners. ‘The vaccine, called rVSV-ZEBOV, was studied in a trial involving 11 841 people in Guinea during 2015,’ the WHO said in a statement. ‘Among the 5 837 people who received the vaccine, no Ebola cases were recorded 10 days or more after vaccination.’ Patients were either vaccinated immediately or after three weeks, and because Ebola has an incubation time of two to 21 days, the latter acted as the ‘control’ group. Initially, only people over the age of 18 were included in the trial but after positive results were recorded (apart from some minor side effects such as headaches, fatigue and muscle pain), the trial expanded to include children who were at least six years old. ‘Ebola left a devastating legacy in our country,’ says Dr KeÏta Sakoba, director of Guinea’s National Agency for Health Security. ‘We are proud that we have been able to contribute to developing a vaccine that will prevent other nations from enduring what we endured.’ 31 January 2017 Image: Gallo/Getty Images