Effect of sensitivity of the surveillance system. The delay of the peak increases with the proportion of detected cases. When 10% of cases are detected and these are followed-up with CCM1 for the initial 500 cases (but no CCM2) the delay is 6 days, but can be raised to 20 days (gain of 2 weeks) when case detection is improved to 30%. The combined approach of 500 cases targeted with CCM1 and additional 10,000 cases with CCM2 the gain based on the improved case detection results in an increase for up to 6 weeks (11 to 50 days; Figure S3 , Table 2 ).