Fig. 6

Impact of interventions on disease elimination. a Probability of disease elimination over time, assuming different values for the number of traced contacts per case since February 25, 2014. Blue bars represent a situation comparable to what was observed in April 2015. b As a but assuming ring vaccination starting on March 23, 2015, enrollment 3 days after the admission of ring index cases to ETU, 90 % vaccine efficacy, 6 days for vaccinated individuals to develop protective immunity, and vaccine administered to 90 % of adults (≥18 years old). In 50 % of rings, vaccine is administered with a delay of 21 days with respect to immediately vaccinated rings. c As b but vaccine is administered to 90 % of all individuals and all rings are vaccinated at the time of enrollment. The number of traced contacts matches the data (see Methods and Additional file 1) until February 25, 2015; then, it is assumed to be constant over time until the end of the simulation, at the level reported in the legend