Mass drug administration (MDA) of antifilarial drugs is the main strategy for the elimination of lymphatic filariasis (LF). Recent clinical trials indicated that the triple-drug therapy with ivermectin, diethylcarbamazine, and albendazole (IDA) is much more effective against LF than the widely used two-drug combinations (albendazole plus either ivermectin or diethylcarbamazine). For IDA-based MDA, the stop-MDA decision is made based on microfilariae (mf) prevalence in adults. In this study, we assess how the probability of eventually reaching elimination of transmission depends on the critical threshold used in transmission assessment surveys (TAS-es) to define whether transmission was successfully suppressed and triple-drug MDA can be stopped. This analysis focuses on treatment-naive Indian settings. We do this for a range of epidemiological and programmatic contexts, using the established LYMFASIM model for transmission and control of LF. Based on our simulations, a single TAS, one year after the last MDA round, provides limited predictive value of having achieved suppressed transmission, while a higher MDA coverage increases elimination probability, thus leading to a higher predictive value. Every additional TAS, conditional on previous TAS-es being passed with the same threshold, further improves the predictive value for low values of stop-MDA thresholds. An mf prevalence threshold of 0.5% corresponding to TAS-3 results in ≥95% predictive value even when the MDA coverage is relatively low.

中文翻译：

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在印度未接受治疗的环境中，用 IDA 对抗淋巴丝虫病三重药物治疗后，基于微丝蚴的 MDA 阈值的预测价值

抗丝虫药物的大规模给药（MDA）是消除淋巴丝虫病（LF）的主要策略。最近的临床试验表明，伊维菌素、二乙基卡马嗪和阿苯达唑 (IDA) 三药疗法对 LF 的治疗效果比广泛使用的双药组合（阿苯达唑加伊维菌素或二乙基卡马嗪）要有效得多。对于基于 IDA 的 MDA，停止 MDA 的决定是根据成人中微丝蚴 (mf) 的患病率做出的。在这项研究中，我们评估了最终达到消除传播的概率如何取决于传播评估调查 (TAS-es) 中使用的关键阈值，以确定传播是否被成功抑制以及三药 MDA 是否可以停止。本分析重点关注未经治疗的印度环境。我们针对一系列流行病学和规划背景进行了这项工作，使用已建立的 LYMFASIM 模型来传播和控制 LF。根据我们的模拟，在最后一轮 MDA 一年后，单个 TAS 提供的实现抑制传播的预测价值有限，而较高的 MDA 覆盖范围会增加消除概率，从而产生更高的预测价值。每个额外的 TAS（以之前的 TAS-es 以相同阈值通过为条件）会进一步提高对低值停止 MDA 阈值的预测值。即使 MDA 覆盖率相对较低，与 TAS-3 相对应的 0.5% mf 患病率阈值也会产生 ≥95% 的预测值。