The potential impact of male circumcision on HIV in Sub-Saharan Africa.
The potential impact of male circumcision on HIV in Sub-Saharan Africa.
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DOI：
10.1371/journal.pmed.0030262
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发表时间：
2006-07
期刊：
影响因子：
15.8
通讯作者：
Auvert B
中科院分区：
文献类型：
--
作者：
Williams BG;Lloyd-Smith JO;Gouws E;Hankins C;Getz WM;Hargrove J;de Zoysa I;Dye C;Auvert B
一项随机对照试验（RCT）表明，男性包皮环切术（MC）可将女性向男性的艾滋病毒性传播减少60% (32% - 76%;95% CI)，为减少艾滋病毒性传播提供了一种经证实有效的干预措施。我们探讨了这一发现对促进MC作为撒哈拉以南非洲地区控制艾滋病毒的公共卫生干预措施的影响。使用动态模拟模型，我们考虑了MC对男性和女性以及包皮环切术和未包皮环切术男性中HIV相对流行率的影响。利用国家层面的艾滋病毒流行率和MC数据，我们估计了未来10年、20年和30年，MC覆盖率增加对撒哈拉以南非洲地区艾滋病毒发病率、艾滋病毒流行率和艾滋病毒相关死亡的影响。假设在未来十年实现MC的全面覆盖，我们考虑三种情况，其中传播减少是由随机对照试验中观察到的传播减少的最佳估计和上下95%置信限给出的。在撒哈拉以南非洲，MC可在今后十年避免200万（110 - 380万）例新的艾滋病毒感染和30万（10 - 50万）例死亡。在这之后的十年中，它可以避免370万（190 - 750万）新的艾滋病毒感染和270万（150 - 530万）例死亡，其中大约四分之一的事件病例和避免的死亡发生在南非。我们表明，a) MC将使女性感染者的比例从52%增加到58%；B)在同质混合但并非所有男性都做过包皮环切术的地方，做过包皮环切术的男性感染的流行率可能是未做过包皮环切术的男性的80%左右；c) MC相当于一种干预措施，如接种疫苗或增加避孕套的使用，可使双向传播减少37%。该分析仅基于一项随机对照试验的结果，但如果该试验的结果得到证实，我们认为MC可以大大减轻非洲的艾滋病毒负担，特别是在MC患病率低而艾滋病毒患病率高的南部非洲。虽然对艾滋病毒阴性男性的保护效益将是立竿见影的，但MC对艾滋病毒相关疾病和死亡的全面影响要在10到20年后才能显现出来。非洲是受艾滋病毒/艾滋病影响最严重的大陆，必须考虑减少艾滋病毒感染蔓延的一切可能手段。男性包皮环切术在非洲许多地区已经有数百年的传统。接受包皮环切术的男孩通常在童年晚期或青少年早期进行。几年前人们注意到，在非洲，所有男孩都接受包皮环切术的群体比那些没有包皮环切传统的群体感染艾滋病毒/艾滋病的病例要少。这一发现引发了一种观点，即包皮环切术可能在一定程度上保护人们免受艾滋病毒的侵害，尽管人们认识到，这些人群之间的其他一些未知的差异实际上可能是重要因素。2005年，南非奥兰治农场地区报道了一项试验，在该试验中，未割包皮的男性有机会接受包皮环切。同意接受手术的男性被随机分为两组，一组立即接受手术，另一组在两年后接受手术。在接下来的18个月里，未行包皮环切术的男性感染艾滋病毒的新病例数量要高得多。因此，包皮环切术似乎确实提供了一种预防感染的措施。据估计，这种保护作用约为60%。类似的试验正在非洲其他地区进行，但目前还没有结果。如果南非试验所显示的包皮环切术的有效性是正确的，那么，作为一系列减少艾滋病毒传播措施的一部分，鼓励男性包皮环切术似乎是合乎逻辑的。估计一下通过推广男性包皮环切术可以预防多少新病例和挽救多少生命，将是有用的。计算必须考虑到各种因素，例如目前的艾滋病毒感染水平因国家而异，以及许多男性已经接受过包皮环切手术的事实。这项研究不涉及收集任何新数据。研究人员使用数学模型进行计算。他们的模型是基于奥兰治农场试验的数据，以及来自撒哈拉以南非洲各国的信息，包括做过包皮环切术的男性比例和艾滋病毒呈阳性的比例。他们假设，如果包皮环切术得到大力推广，这些国家的所有男性将在10年内接受包皮环切术。他们计算了在10年、20年和30年的时间里可以预防的新病例数量和可以挽救的生命。他们的最佳估计是，随着男性包皮环切术的推广，在10年内将避免200万例病例和30万例死亡。根据研究人员的模型，在接下来的十年里，将会有370万例病例和270万例死亡被避免。最初的影响将主要集中在男子身上，但艾滋病毒阳性男子人数的减少也将及时降低妇女受感染的风险。总的来说，在这些计算的基础上，男性包皮环切术将减少大约37%的感染率——包括女性对男性和男性对女性的传播。影响的大小因国而异；与撒哈拉以南非洲其他地区相比，艾滋病毒感染率高且包皮环切率相对较低的南部非洲将是最大的。仅靠男性包皮环切不能控制非洲的艾滋病毒/艾滋病流行病。即使是割过包皮的男性也会被感染，尽管他们这样做的风险要低得多。然而，这组科学家呼吁将男性包皮环切术推广成为艾滋病控制项目的一个主要部分。他们的结果仅基于一项研究（橙农场试验）的发现，当进一步的研究完成后，重复计算将是很重要的。请通过此摘要的在线版本http://dx.doi.org/10.1371/journal.pmed.0030262访问这些网站：•橙色农场试验发表在《公共科学图书馆医学》上。《联合国艾滋病毒/艾滋病联合规划署》（艾滋病规划署）还在同一期杂志上发表了几篇讨论该试验的文章，介绍了全世界艾滋病毒/艾滋病的流行状况和预防战略。它每年发布一份报告，并有关于广泛主题的文件•AEGIS是世界上最大的可搜索的艾滋病毒和艾滋病数据库。•世界银行全球艾滋病毒/艾滋病项目有一份关于男性包皮环切术和艾滋病毒感染的报告。一项基于一项试验和当前艾滋病毒流行率和男性包皮环切术（MC）的国家数据的模型研究发现，非洲MC的增加可能会在10-12年内使艾滋病毒流行率大幅下降。
A randomized controlled trial (RCT) has shown that male circumcision (MC) reduces sexual transmission of HIV from women to men by 60% (32%−76%; 95% CI) offering an intervention of proven efficacy for reducing the sexual spread of HIV. We explore the implications of this finding for the promotion of MC as a public health intervention to control HIV in sub-Saharan Africa. Using dynamical simulation models we consider the impact of MC on the relative prevalence of HIV in men and women and in circumcised and uncircumcised men. Using country level data on HIV prevalence and MC, we estimate the impact of increasing MC coverage on HIV incidence, HIV prevalence, and HIV-related deaths over the next ten, twenty, and thirty years in sub-Saharan Africa. Assuming that full coverage of MC is achieved over the next ten years, we consider three scenarios in which the reduction in transmission is given by the best estimate and the upper and lower 95% confidence limits of the reduction in transmission observed in the RCT. MC could avert 2.0 (1.1−3.8) million new HIV infections and 0.3 (0.1−0.5) million deaths over the next ten years in sub-Saharan Africa. In the ten years after that, it could avert a further 3.7 (1.9−7.5) million new HIV infections and 2.7 (1.5−5.3) million deaths, with about one quarter of all the incident cases prevented and the deaths averted occurring in South Africa. We show that a) MC will increase the proportion of infected people who are women from about 52% to 58%; b) where there is homogenous mixing but not all men are circumcised, the prevalence of infection in circumcised men is likely to be about 80% of that in uncircumcised men; c) MC is equivalent to an intervention, such as a vaccine or increased condom use, that reduces transmission in both directions by 37%. This analysis is based on the result of just one RCT, but if the results of that trial are confirmed we suggest that MC could substantially reduce the burden of HIV in Africa, especially in southern Africa where the prevalence of MC is low and the prevalence of HIV is high. While the protective benefit to HIV-negative men will be immediate, the full impact of MC on HIV-related illness and death will only be apparent in ten to twenty years. Africa is the continent most affected by HIV/AIDS, and it is important to consider all possible means of reducing the spread of HIV infection. Male circumcision has been a tradition in many parts of Africa for hundreds of years. Boys who are circumcised usually have it done in late childhood or their early teenage years. It was noticed some years ago that those African groups in which circumcision is routinely done on all boys have fewer cases of HIV/AIDS than are found in groups where circumcision is not a tradition. This finding gave rise to the idea that circumcision might give a degree of protection against HIV, though it was recognised that some other, unknown difference between these groups of people might actually be the important factor. In 2005 a trial was reported from the Orange Farm area of South Africa, in which uncircumcised men were offered the chance to be circumcised. The men who agreed were divided at random into those who had the operation straightaway and those who were to have it two years later. During the next 18 months, the number of new cases of HIV infection was much higher amongst the men who had not been circumcised. Circumcision did therefore seem to offer a measure of protection against infection. This protective effect was estimated at being about 60%. Similar trials are under way in other parts of Africa but there are no results available from them at this stage. If the level of effectiveness of circumcision suggested by the South African trial is correct, then, as one part of a range of measures to reduce the spread of HIV, it would seem logical to encourage the practice of male circumcision. It would be useful to have an estimate of just how many new cases could be prevented and how many lives would be saved by the promotion of male circumcision. Calculations would have to allow for various factors, such as the present level of HIV infection, which varies from one country to another, and the fact that many men are already circumcised. This research did not involve collecting any new data. The researchers used mathematical modelling to make calculations. They based their model on data from the Orange Farm trial and on information from various sub-Saharan African countries on the proportion of men who are circumcised and the proportion who are HIV-positive. They made the assumption that if circumcision is intensively promoted, all men in those countries will be circumcised in 10 years time. They calculated the number of new cases that would be prevented and the lives that would be saved in ten years, 20 years, and 30 years time. Their best estimate is that with the promotion of male circumcision, two million cases and 0.3 million deaths will be avoided in ten years time. Over the following ten years, according to the researchers' model, a further 3.7 million cases and 2.7 million deaths would be prevented. Most of the initial impact would be in men, but the reduction in the number of HIV-positive men would in time also lower the risk of women becoming infected. Overall, on the basis of these calculations, male circumcision would reduce the rate of infections by about 37%—both female-to-male and male-to-female transmission. The size of the impact would vary from one country to another; it would be greatest in southern Africa where HIV infection rates are high and circumcision rates relatively low compared with the rest of sub-Saharan Africa. Male circumcision alone cannot bring the HIV/AIDS epidemic in Africa under control. Even circumcised men can become infected, though their risk of doing so is much lower. However, the researchers call for the promotion of male circumcision to become a major part of AIDS control programmes. Their results are based on the findings of just one study (the Orange Farm trial), and it will be important to repeat the calculations when further studies have been completed. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030262: • The Orange Farm trial was published in PLoS Medicine. Several articles discussing the trial were also published in the same issue of the journal • The Joint United Nations Programme on HIV/AIDS (UNAIDS) has information about the state of the HIV/AIDS epidemic and prevention strategies worldwide. It produces an annual report and has documents on a wide range of topics • AEGIS is the world's largest searchable database on HIV and AIDS. • Many organizations provide information on AIDS prevention—for example, the Terrence Higgins Trust • The World Bank's Global HIV/AIDS Program has a report about male circumcision and HIV infection A modelling study, based on one trial plus national figures for current prevalence of HIV and of male circumcision (MC), found increasing MC in Africa could produce major fall in HIV prevalence in 10-12 years.