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目的采用动力学模型模拟隔离措施在学校甲型H1N1流感暴发疫情处理中的效果。方法根据甲型H1N1流感疾病特征和学校人口学特点,建立易感者-潜伏期-显性/隐性感染者-移出者(susceptible-exposed-infectious/asymptomatic-removed,SEIAR)模型,对长沙市某校甲型H1N1流感暴发疫情进行模拟,采用卡方检验评价模拟结果与实际疫情的拟合优度,并确定模型的关键参数。在SEIAR模型基础上引入隔离措施,构建易感者-潜伏期-显性/隐性感染者-移出者-隔离者(susceptible-exposed-infectious/asymptomatic-removed-quarantine,SEIARQ)模型。为方便基层公共卫生工作者,将对患者(显性感染者)的隔离等分为10个等级(10%、20%、…、90%、100%),以评估不同隔离比例的效果。结果无干预情况下,疫情基本再生数(λ0)为5.64,疫情持续31天,人群感染率高达99.51%。在对显性感染者采取隔离措施后,随着隔离比例的增加,人群感染率(含显性和隐性感染)和人群罹患率(仅含显性感染)逐渐下降。当隔离全部显性感染患者后,可减少63%的罹患率。在只隔离显性感染措施时,仅当隔离比例超过30%,疫情控制效果才相对显著。结论单纯隔离患者最多能降低63%的人群甲型H1N1流感罹患率。各地公共卫生机构应根据当地人力和物力情况,采取部分隔离(隔离比例≥30%)与其他措施相结合的方式阻断甲型H1N1疫情的发展。
Objective To adopt the kinetic model to simulate the effect of isolation measures in the outbreak of influenza A (H1N1) in schools. Methods According to the characteristics of Influenza A (H1N1) and school demographic characteristics, a model of susceptible-exposed-infectious / asymptomatic-removed (SEIAR) was established. School A H1N1 influenza outbreaks were simulated, using chi-square test to evaluate the simulation results and the actual goodness of fit of the epidemic, and to determine the key parameters of the model. Based on the SEIAR model, isolation measures were introduced to construct the susceptible-exposed-infectious / asymptomatic-removed-quarantine (SEIARQ) model. In order to facilitate grassroots public health workers, the isolation of patients (dominant infections) is divided equally into 10 grades (10%, 20%, ..., 90%, 100%) to assess the effect of different segregation rates. Results In the absence of intervention, the basic number of reproductive events (λ0) was 5.64 and the epidemic lasts for 31 days. The infection rate of the population is as high as 99.51%. After isolation of dominant infections, the population infection rate (including dominant and recessive infections) and the population attack rate (dominant infection only) gradually decreased as the isolation ratio increased. When isolated from all patients with dominant infection, can reduce the attack rate of 63%. When only the dominant infection is isolated, the effect of the outbreak control is only significant when the isolation ratio exceeds 30%. Conclusion Isolated patients can reduce the attack rate of type A H1N1 influenza by up to 63% at most. Public health agencies at all levels should, according to local manpower and material conditions, adopt a method of partial segregation (≥30% segregation) in combination with other measures to block the development of the H1N1 epidemic.