[Analysis on 2071 cases excluded from severe acute respiratory syndrome in Beijing]

To examine the characteristics of cases excluded from severe acute respiratory syndrome (SARS) and the reasons for exclusion.

2071 probable or suspected cases excluded from SARS between March and June, 2003 were analyzed.

Two-thirds of the excluded cases were males. Construction workers, students and retired people ranked top three in all the occupation categories. Three peaks appeared in the dates of exclusion, and the most obvious one was from June 7 to June 13. There were two peaks in the distribution of time period from onset to exclusion, one was six to ten days and the other was forty-eight to fifty-two days after onset. Patients with history of close contact were more likely to be excluded within fifty days after onset than those without close history of contact. Pneumonia, common cold and lung infection were the leading causes for correction in the 1211 excluded cases.

Study on the diagnosis and differential diagnosis should be emphasized.