Model parameters and outbreak control for SARS

Control of the 2002-2003 severe acute respiratory syndrome (SARS) outbreak was based on rapid diagnosis coupled with effective patient isolation. We used uncertain ty and sensitivity analysis of the basic reproductive number R _O to assess the role that model parameters play in outbreak control. The transmission rate and isolation effectiveness have the largest fractional effect on R_O. We estimated the distribution of the reproductive number R_O under perfect isolation conditions. The distribution lies in the interquartile range 0.19-1.08, with a median of 0.49. Even though the median of R_O is <1, we found that 25% of our R_O distribution lies at R_O >1, even with perfect isolation. This implies the need to simultaneously apply more than one method of control.