Center for Modeling, Planning and Policy Analysis, Avenir Health, Glastonbury, CT, USA.
Centre for Infectious Disease Epidemiology and Research (CIDER), University of Cape Town, Cape Town, South Africa.
J Int AIDS Soc. 2021 Sep;24 Suppl 5(Suppl 5):e25778. doi: 10.1002/jia2.25778.
The Spectrum/AIM model is used by national HIV programs and UNAIDS to prepare annual estimates of key HIV indicators. This article describes key updates to paediatric and adult models for the 2021 round of HIV estimates.
Potential updates to Spectrum arise due to newly available data, new analyses of existing data, and the need for new issues to be addressed. Updates are guided by experts through the UNAIDS Reference Group on Estimates, Modelling and Projections. Changes are tested and assessed for impact before being accepted into the final model.
Spectrum tracks children living with HIV by CD4% for ages 0-4 and CD4 count for ages 5-14. Data from IeDEA treatment sites have been used to map the transition from CD4% to CD4 count at age 5. Breastfeeding patterns in sub-Saharan Africa have been updated with the latest survey data and estimates of continuation on antiretroviral therapy (ART) with breastfeeding have been revised based on recent studies. Model assumptions about the CD4 counts of people who drop out of ART have been revised to account for CD4 count increases while on treatment. If available, monthly data on numbers on ART can now be used to estimate the effects of COVID-19-related disruptions during 2020.
These changes are intended to provide more accurate estimates of HIV burden. The effects of these changes on paediatric indicators are small except in countries with new surveys that might have updated patterns of breastfeeding. Changes to the adult model have little effect on total new infections. AIDS-related deaths will be somewhat lower in countries that have data on ART drop out but might be increased by HIV care disruptions due to COVID-19. The updated model uses newly available data to improve the estimation of paediatric and adult HIV indicators.
国家艾滋病规划署和艾滋病规划署利用 Spectrum/AIM 模型来编制关键艾滋病毒指标的年度估计数。本文介绍了 2021 年艾滋病毒估计数一轮中针对儿科和成人模型的主要更新内容。
由于新出现的数据、对现有数据的新分析以及需要解决新问题， Spectrum 可能会进行更新。更新内容由艾滋病规划署估计、建模和预测参考小组的专家指导。在被接受纳入最终模型之前，会对更改内容进行测试和评估影响。
Spectrum 按照 CD4%对年龄 0-4 岁的儿童和 CD4 计数对年龄 5-14 岁的儿童进行艾滋病毒携带儿童的追踪。从 IeDEA 治疗点获得的数据被用于在年龄 5 岁时将 CD4%过渡到 CD4 计数的映射。撒哈拉以南非洲的母乳喂养模式已经使用最新的调查数据进行了更新，并且根据最近的研究对母乳喂养时继续抗逆转录病毒治疗（ART）的估计进行了修订。模型对中断 ART 治疗的人的 CD4 计数的假设已进行修订，以说明在治疗期间 CD4 计数的增加。如果有可用的每月 ART 人数数据，现在可以用来估计 2020 年与 COVID-19 相关的中断对治疗的影响。
这些更改旨在提供更准确的艾滋病毒负担估计数。除了有新的调查可能更新母乳喂养模式的国家外，这些更改对儿科指标的影响很小。成人模型的更改对总新增感染的影响不大。有 ART 中断数据的国家的艾滋病相关死亡人数可能会降低，但由于 COVID-19 导致的艾滋病毒护理中断可能会增加。更新后的模型利用新出现的数据来改善儿科和成人艾滋病毒指标的估计。
