Analysis of the current SARS epidemic and the forecast for Beijing

We set up a statistical analysis model by taking into account the average duration of the direct contagion of a SARS case and its average contagion probability per day. The calculation shows that the average duration of the direct contagion is about 20 days, which is not sensitive to the place and phase of the epidemic. On the other hand, the average contagion probability varies with social conditions. The probability is high in the initial phase but changes to a significantly smaller value in the controlled phase. If during the last phase the strictness of control in Beijing is comparable to that of Hong Kong in the corresponding phase, the number of new SARS cases may abate to a few per day in the first half of June and down to zero in mid－July, with the accumulated total more than 3100. If the control strength is comparable to that of Guangdong in the corresponding phase, it will take at least one more month to reach the above performance and the accumulated total will be about 3800.