Brown T, Grassly N C, Garnett G, Stanecki K
Sex Transm Infect. 2006 Jun;82 Suppl 3(Suppl 3):iii34-40. doi: 10.1136/sti.2006.020230.
UNAIDS has developed the Estimation and Projection Package (EPP) as a tool for national programmes to use for making national estimates and short term projections of HIV prevalence. EPP provides direct input to Spectrum, which produces incidence, deaths, and AIDS impacts.
The latest version, EPP 2005, includes substantial methodological improvements over the previous version. These include: (1) parallel, but unique, interfaces for generalised and concentrated epidemics; (2) use of maximum likelihood fitting procedures; (3) a new procedure, known as level fits, adjusting for expansion of national surveillance systems into lower prevalence sites; (4) provisions for handling turnover in at-risk populations, including the reassignment of HIV positive former members to lower risk populations; and (5) user-defined calibration to HIV prevalence levels from general population or other epidemiological surveys.
Following regional training in mid 2005, this new version has been applied by many national programmes to make their end of 2005 estimates of HIV infections. UNAIDS has combined these national estimates to form the 2005 global HIV and AIDS estimates.
EPP 2005 is a substantial improvement over previous versions, forming a solid base for the next round of modifications. Proposed modifications for that next version are presented for the reader's information.
联合国艾滋病规划署（UNAIDS）开发了估计与预测软件包（EPP），作为国家项目用于进行全国艾滋病毒感染率估计和短期预测的工具。EPP为Spectrum提供直接输入数据，Spectrum可生成发病率、死亡率及艾滋病影响情况。
最新版本EPP 2005在方法上较前一版本有大幅改进。这些改进包括：（1）针对广泛流行和集中流行设置并行但独特的界面；（2）使用最大似然拟合程序；（3）一种名为水平拟合的新程序，用于调整国家监测系统向低感染率地区扩展的情况；（4）处理高危人群更替的规定，包括将艾滋病毒呈阳性的 former members重新分配到低风险人群；（5）根据一般人群或其他流行病学调查的艾滋病毒感染率水平进行用户定义校准。
在2005年年中进行区域培训后，许多国家项目已应用此新版本来进行2005年底艾滋病毒感染情况的估计。UNAIDS将这些国家估计数汇总，形成了2005年全球艾滋病毒与艾滋病估计数。
EPP 2005较之前版本有显著改进，为下一轮修改奠定了坚实基础。文中为读者提供了下一版本拟进行修改的相关信息。
