Key Laboratory of Molecular Epidemiology of Hunan Province, School of Medicine, Hunan Normal University, Changsha, Hunan410081, People's Republic of China.
Epidemiol Infect. 2020 Mar 17;148:e56. doi: 10.1017/S0950268819002188.
Varicella is an acute respiratory infectious diseases, with high transmissibility and quick dissemination. In this study, an SEIR (susceptible-exposed-infected-recovered) dynamic model was established to explore the optimal prevention and control measures according to the epidemiological characteristics about varicella outbreak in a school in a central city of China. Berkeley Madonna 8.3.18 and Microsoft Office Excel 2010 software were employed for the model simulation and data management, respectively. The result showed that the simulated result of SEIR model agreed well with the reported data when β (infected rate) equal to 0.067. Models showed that the cumulative number of cases was only 13 when isolation adopted when the infected individuals were identified (assuming isolation rate was up to 100%); the cumulative number of cases was only two and the TAR (total attack rate) was 0.56% when the vaccination coefficient reached 50%. The cumulative number of cases did not change significantly with the change of efficiency of ventilation and disinfection, but the peak time was delayed; when δ (vaccination coefficient) = 0.1, m (ventilation efficiency) = 0.7 or δ = 0.2, m = 0.5 or δ = 0.3, m = 0.1 or δ = 0.4 and above, the cumulative number of cases would reduce to one case and TAR would reduce to 0.28% with combined interventions. Varicella outbreak in school could be controlled through strict isolation or vaccination singly; combined interventions have been adopted when the vaccination coefficient was low.
水痘是一种急性呼吸道传染病，具有传染性强、传播速度快的特点。本研究根据中国中部某市某学校水痘暴发的流行病学特征，建立 SEIR（易感-暴露-感染-恢复）动力学模型，探索最佳的预防控制措施。采用 Berkeley Madonna 8.3.18 和 Microsoft Office Excel 2010 软件进行模型模拟和数据管理。结果表明，当β（感染率）等于 0.067 时，SEIR 模型的模拟结果与报告数据吻合较好。模型显示，当感染者被发现时采取隔离措施（假设隔离率达到 100%），累计病例数仅为 13 例；当接种系数达到 50%时，累计病例数仅为 2 例，总发病率（TAR）为 0.56%。通风和消毒效率的变化对累计病例数影响不大，但会延迟峰值时间；当δ（接种系数）=0.1、m（通风效率）=0.7 或δ=0.2、m=0.5 或δ=0.3、m=0.1 或δ=0.4 及以上时，联合干预可使累计病例数减少到 1 例，TAR 降低到 0.28%。学校水痘暴发可通过严格隔离或接种疫苗单独控制；当接种系数较低时，应采取联合干预措施。
