Gouws E, White P J, Stover J, Brown T
Department of Policy, Evidence and Partnership, Joint United Nations Programme on HIV/AIDS, UNAIDS, Geneva, Switzerland.
Sex Transm Infect. 2006 Jun;82 Suppl 3(Suppl 3):iii51-55. doi: 10.1136/sti.2006.020164.
Patterns of transmission of HIV are different among different regions of the world and change over time within regions. In order to adapt prevention strategies to changing patterns of risk, we need to understand the behaviours that put people at risk of infection and how new infections are distributed among risk groups.
A model is described to calculate the expected incidence of HIV infections in the adult population by mode of exposure using the current distribution of prevalent infections and the patterns of risk within different populations. For illustration the model is applied to Thailand and Kenya.
New infections in Kenya were mainly transmitted through heterosexual contact (90%), while a small but significant number were related to injecting drug use (4.8%) and men who have sex with men (4.5%). In Thailand, the epidemic has spread over time to the sexual partners of vulnerable groups and in 2005 the majority of new infections occurred among the low risk heterosexual population (43%). Men having sex with men accounted for 21% and sex work (including sex workers, clients, and partners of clients) for 18% of new infections. Medical interventions did not contribute significantly to new infections in either Kenya or Thailand.
The model provides a simple tool to inform the planning of effective, appropriately targeted, country specific intervention programmes. However, better surveillance systems are needed in countries to obtain more reliable biological and behavioural data in order to improve the estimates of incidence by risk group.
全球不同地区的艾滋病毒传播模式各异，且各地区随时间推移也会发生变化。为使预防策略适应不断变化的风险模式，我们需要了解导致人们面临感染风险的行为，以及新感染在不同风险群体中的分布情况。
描述了一个模型，该模型利用现患感染的当前分布以及不同人群中的风险模式，按暴露方式计算成年人群中艾滋病毒感染的预期发病率。为举例说明，该模型应用于泰国和肯尼亚。
肯尼亚的新感染主要通过异性接触传播（90%），而一小部分但数量可观的感染与注射吸毒（4.8%）和男男性行为（4.5%）有关。在泰国，随着时间推移，疫情已蔓延至弱势群体的性伴侣，2005年大多数新感染发生在低风险异性恋人群中（43%）。男男性行为者占新感染的21%，性工作（包括性工作者、嫖客及其性伴侣）占新感染的18%。在肯尼亚和泰国，医疗干预对新感染的影响均不显著。
该模型提供了一个简单工具，可为制定有效、针对性强的国家特定干预计划提供参考。然而，各国需要更好的监测系统，以获取更可靠的生物学和行为数据，从而改进按风险群体对发病率的估计。
