Williams J R, Nokes D J, Medley G F, Anderson R M
Wellcome Centre for Epidemiology of Infectious Disease, Department of Zoology, University of Oxford, London, UK.
Epidemiol Infect. 1996 Feb;116(1):71-89. doi: 10.1017/s0950268800058970.
Complex hepatitis B (HBV) epidemiology makes it difficult to evaluate and compare effectiveness of different immunization policies. A method for doing so is presented using a mathematical model of HBV transmission dynamics which can represent universal infant and adolescent vaccination strategies and those targeted at genito-urinary (GU) clinic attenders and infants born to infectious mothers. Model structure, epidemiological underpinning, and parameterization, are described. Data from the UK National Survey of Sexual Attitudes and Lifestyles is used to define patterns of sexual activity and GU clinic attendance; data deficiencies are discussed, in particular that of UK seroprevalence of HBV markers stratified by age, sex, and risk factors. General model predictions of endemic HBV marker prevalence in homosexual and heterosexual populations seem consistent with published UK data. The simulations exhibit non-linearities in the impact of different vaccination strategies. Estimated number of carriers prevented per vaccine dose for each strategy provides a measure of costs and benefits, varying temporally over the course of a programme, and with level of vaccine coverage. Screening before vaccination markedly increases payback per dose in homosexuals but not in heterosexuals; mass infant vaccination gives the poorest effectiveness ratio and vaccination of infants after antenatal screening the best; in general, increasing vaccine coverage yields lower pay-back per dose. The model provides a useful framework for evaluating costs and benefits of immunization programmes, but for precise quantitative comparison more UK epidemiological data is urgently needed.
复杂的乙型肝炎（HBV）流行病学情况使得评估和比较不同免疫策略的有效性变得困难。本文提出了一种方法，使用HBV传播动力学的数学模型，该模型可以代表普遍的婴幼儿和青少年疫苗接种策略，以及针对泌尿生殖科（GU）门诊患者和感染母亲所生婴儿的疫苗接种策略。文中描述了模型结构、流行病学基础和参数设置。利用英国全国性态度和生活方式调查的数据来定义性行为模式和GU门诊就诊情况；讨论了数据不足之处，特别是按年龄、性别和风险因素分层的英国HBV标志物血清流行率数据的不足。该模型对同性恋和异性恋人群中HBV标志物流行情况的总体预测似乎与已发表的英国数据一致。模拟结果显示不同疫苗接种策略的影响存在非线性。每种策略每剂疫苗预防的携带者估计数量提供了一种成本效益衡量方法，在项目实施过程中随时间变化，且与疫苗接种覆盖率水平有关。接种前进行筛查显著提高了同性恋者每剂疫苗的回报，但对异性恋者没有影响；大规模婴幼儿疫苗接种的效益比最差，产前筛查后对婴儿进行疫苗接种的效益比最佳；一般来说，提高疫苗接种覆盖率会使每剂疫苗的回报降低。该模型为评估免疫规划的成本效益提供了一个有用的框架，但要进行精确的定量比较，迫切需要更多的英国流行病学数据。
