The Effectiveness of Contact Tracing in Emerging Epidemics

Klinkenberg, Don; Fraser, Christophe; Heesterbeek, Hans

ous periods (panels 2A,C, and 3A,C): it is hardly effective without delay, and ineffective already if d = 0.1. SARS control requires a tracing probability p c *,121/R 0 pre which is relatively insensitive to delays. Smallpox requires p c * = 121/R 0 pre , and is insensitive to delays up to some point (d<0.6) where tracing becomes quickly ineffective. Finally, FMD can be traced effectively only if d is small, but it is sensitive to delays already if d is small and requires a tracing probability p c *.121/R 0 pre . Measured in real time (panel 4B), effectiveness of tracing appears to be highly dependent on the actual generation time of the infection. Influenza control is hardly possible, FMD control will be difficult, whereas tracing is likely to be successful for smallpox and SARS.