【摘要】 目的　探索严重急性呼吸系统综合征 (SARS)在家庭内和医院内聚集性传播和产生“超级传播事件”的机制。　方法　运用SARS传播数学模型 ,根据两个主要参数—接触率和感染效率的变动 ,估算SARS在小人群中的传播 ,以及加强防护措施对控制医院内传播的作用。　结果　定量地给出了家庭内和医院内聚集性传播所需的接触率和感染效率的条件 ,从理论上揭示了家庭内和医院内聚集性传播的机制 ;通过加强对病人 (包括疑似病例 )的隔离治疗和医护人员的防护降低接触率和感染效率 ,可以有效防止聚集性传播 ;防护措施必须使感染效率下降 85 %以上 ,才能使医院内传播的基本繁殖率降至临界值以下。　结论　SARS病毒较强的传播性和致病力导致较高的感染效率 ,以及家属和医护人员与病人不可避免的密切接触 ,和某些特殊的环境条件下被大大地提高的接触率 ,是造成家庭内、医院内和公共交通工具内聚集性传播进而产生“超级传播事件”的主要因素。更多还原

【Abstract】 Objective Approach to the mechanism of producing cluster transmission of SARS in families and hospitals and the “super-spread events”(SSEs). Methods Estimating SARS transmission in small groups and the effect of reinforcing protection measures on controlling transmission in hospitals by using the mathematical model recently developed by the authors,and by changing the two main parameters,the contact rate and infection efficiency. Results The conditions of contact rates and infection eficiency needed for cluster transmission of SARS in families and hospitals were quantitatively given and the mechanism of the cluster transmission was revealed theoretically;The cluster transmission is able to be effectively prevented by reducing contact rate and infection efficiency through reinforcing isolation treatment of patients (including suspected cases) and protection of medical staffs;It is necessary to drop the infection efficiency by over 85% through protection measures for reducing the basic reproduction rate below the critical level. Conclusion The high infection efficiency induced by the intense infectivity and pathogenicity of SARS virus,and unavoidable closely contact between relations,medical workers and patients,and the high contact rate greatly increased in special environmental conditions are the determinative factors to induce cluster transmission in families,hospitals and public transports,resulting in the “super-spread events”.更多还原