北京市人群病毒性乙型肝炎表面抗原携带率仓室预测模型建立和控制策略分析

Development of epidemiological compartmental model for HBsAg carrier rate and control policy a- nalysis in Beijing

目的建讧北京市病毒性乙型肝炎表面抗原携带率的流行病学数学模型，并比较不同接种策略对乙肝表面抗原携带率的控制效果。方法利用既往的乙肝血清学调查数据和传染病数学建模思想，由实际资料和文献资料确定传染力等参数，建立由偏微分方程表达的病毒性乙型肝炎表面抗原携带率流行动力学仓室模型。结果建立了包括易感者、潜隐者、临时带毒者、持续带毒者和免疫者五个仓室的病毒性乙型肝炎表面抗原携带率动力学数学模型，模型模拟的结果与实际观察值相符，模型能够反映病毒性乙型肝炎在人群中的传播过程。利用该模型进行预测后发现，在现有接种策略下，大约在10年后全市的乙肝病毒表而抗原携带率降为2％以下；如果改变接种策略，在成人19-50岁年龄组人口进行乙肝疫苗强化接种，可以提前2年将乙肝病毒携带率降到2％以下。结论建立的数学模型能够对现有接种策略下的乙型肝炎的发展趋势给出较为准确和清晰的认识，同时可以对不同接种策略下全人群的HBsAg携带率变化情况进行动态的描述。对成人实施强化免疫策略仅比现行策略提前两年实现区域全人群HBsAg携带率降到2％以下防治目标。

Objective To establish the epidemiological mathematical model and contrast different vaccination strategy＇ effects on HBsAg carrier rate in Beijing. Methods Using previous Hepatitis B sero- logical investigation data and the ideology of infectious disease mathematical model （SIR） , establish the dy- namic compartment model of HBsAg carrier rate expressed by partial differential equations whose parameters are from the actual data and the references. Results Established the dynamic compartment model with five compartments include susceptible and latent period and transient viremia and chronic carriage as well as im- mune. The results from the simulation of the model match well with the actual data. It reflects the process of hepatitis B virus transmission. From the model, we predict that under the existing vaccination strategy, HBsAg carrier rate will decrease below 2% after 10 years and if the immunity vaccination strategy is changedto strengthen vaccination between 15 to 50 age, HBsAg carrier rate will decrease below 2% after 8 - 10 years, 2 years in advance. Conclusion The established mathematical model can give a accurate and clear knowledge of the trend for hepatitis B Virus under the existing immunity vaccination strategy. At the same time, it can give the dynamics description of HBsAg carrier rate of each age groups under different immunity vaccination strategy . Based on the prediction of the model, to attain the object of controlling the HBsAg car- tier rate below 2%, administering adult strengthen immunity strategy will take only 2 years fewer than apply- ing the existing policy.