Abstract: Objective To examine risk factors associated with community transmission of SARS in north China.Method A matched case-control study was conducted in spring 2004.Forty-eight SARS probable cases who had transmitted SARS-CoV to contacts in communities in Beijing,Taiyuan and Inner Mongolia during the 2003 SARS outbreak were recruited as cases group,and 48 SARS probable cases who had not transmitted SARS-CoV to contacts in communities,matched by gender and age,were selected as control group.All data were analyzed using SAS.Results Three factors entered into the Logistic Regression Model in this study.Days stayed in community after onset of SARS and the number of close contacts in community were independent risk factors associated with community transmission of SARS.Wearing a mask was a protective factor,and SARS cases who had not weared masks were 5.53(1.55～19.79) times more likely to transmit SARS-CoV to contacts in communities.Conclusion SARS cases should be admitted to hospitals for isolation and treatment as soon as possible,protective measures should be taken to prevent contacts from SARS-CoV infection in communities before the SARS cases were admitted to hospitals.

Key words: SARS, transmission, community, risk factor