[To develop a model on severe acute respiratory syndrome epidemics to quantitatively evaluate the effectiveness of intervention measures].

Cai, Quan-cai; Jiang, Qing-wu; Xu, Qin-feng; Cheng, Xiang; Guo, Qiang; Sun, Qing-wen; Zhao, Gen-ming

OBJECTIVE To build an epidemic model of severe acute respiratory syndrome (SARS) to be used to quantitatively evaluate the effectiveness of intervention measures. METHODS Following the nature of SARS epidemics, an epidemic model of SARS based on SEIR model of infectious disease was built, in which case management group was set up and some parameters related to control measures were included. As an example, data gathered from Beijing was fitted to illustrate its application to quantitatively evaluate the intervention measures. RESULTS In the newly developed model of epidemics, parameters related to control measures could easily be modified. When scenario assumption was used, a model on SARS outbreak under various circumstances of intervention measures could be set. Thus, quantitative evaluation of intervention measures could perfectly be caried out. Pilot study revealed that the fitness existed in modeling the outbreak of SARS in Beijing and the intervention measures implemented around April 20, 2003, had major contribution to the control of SARS. CONCLUSION The model of SARS epidemics seemed to be stable and reliable to be used to evaluate the effectiveness of intervention measures implemented during the SARS outbreak in a quantitative way.