Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom.
PLoS Negl Trop Dis. 2010 Nov 2;4(11):e862. doi: 10.1371/journal.pntd.0000862.
Mass drug administration (MDA) is part of the current trachoma control strategy, but it can be costly and results in many uninfected individuals receiving treatment. Here we explore whether alternative, targeted approaches are effective antibiotic-sparing strategies.
METHODOLOGY/PRINCIPAL FINDINGS: We analysed data on the prevalence of ocular infection with Chlamydia trachomatis and of active trachoma disease among 4,436 individuals from two communities in The Gambia (West Africa) and two communities in Tanzania (East Africa). An age- and household-structured mathematical model of transmission was fitted to these data using maximum likelihood. The presence of active inflammatory disease as a marker of infection in a household was, in general, significantly more sensitive (between 79% [95%CI: 60%-92%] and 86% [71%-95%] across the four communities) than as a marker of infection in an individual (24% [16%-33%]-66% [56%-76%]). Model simulations, under the best fit models for each community, showed that targeting treatment to households has the potential to be as effective as and significantly more cost-effective than mass treatment when antibiotics are not donated. The cost (2007US$) per incident infection averted ranged from 1.5 to 3.1 for MDA, from 1.0 to 1.7 for household-targeted treatment assuming equivalent coverage, and from 0.4 to 1.7 if household visits increased treatment coverage to 100% in selected households. Assuming antibiotics were donated, MDA was predicted to be more cost-effective unless opportunity costs incurred by individuals collecting antibiotics were included or household visits improved treatment uptake. Limiting MDA to children was not as effective in reducing infection as the other aforementioned distribution strategies.
CONCLUSIONS/SIGNIFICANCE: Our model suggests that targeting antibiotics to households with active trachoma has the potential to be a cost-effective trachoma control measure, but further work is required to assess if costs can be reduced and to what extent the approach can increase the treatment coverage of infected individuals compared to MDA in different settings.
群体药物治疗（MDA）是当前沙眼控制策略的一部分，但它成本高昂，导致许多未感染的人接受了治疗。在这里，我们探讨了替代的、有针对性的方法是否是有效的节省抗生素的策略。
方法/主要发现：我们分析了来自冈比亚（西非）两个社区和坦桑尼亚（东非）两个社区的 4436 个人的眼部感染沙眼衣原体和活动性沙眼疾病的流行率数据。使用最大似然法，我们根据年龄和家庭结构对这些数据进行了传输的数学模型拟合。家庭中活动性炎症疾病作为感染标志物的存在，总体上比个体作为感染标志物的存在更为敏感（在四个社区中分别为 79%[60%-92%]和 86%[71%-95%]）。模型模拟显示，在每个社区的最佳拟合模型下，针对家庭进行治疗有可能与大规模治疗一样有效，并且在没有捐赠抗生素的情况下，成本效益更高。每例感染减少的成本（2007 年美元），在 MDA 中为 1.5 至 3.1，在家庭为目标治疗中为 1.0 至 1.7，假设覆盖范围相同，而如果家庭访问将选定家庭的治疗覆盖率提高到 100%，则为 0.4 至 1.7。假设捐赠了抗生素，除非个人收集抗生素的机会成本被包括在内，或者家庭访问提高了治疗的接受度，否则 MDA 更具成本效益。将 MDA 限制在儿童身上，不如其他上述分配策略有效，无法降低感染率。
结论/意义：我们的模型表明，将抗生素针对活动性沙眼的家庭进行靶向治疗，有可能成为一种具有成本效益的沙眼控制措施，但需要进一步的工作来评估在不同环境下，该方法是否可以降低成本以及在多大程度上可以提高感染个体的治疗覆盖率，与 MDA 相比。
