Simulating the effect of evaluation unit size on eligibility to stop mass drug administration for lymphatic filariasis in Haiti

Existing guidelines for delimiting the geographic areas to conduct transmission assessment surveys (TAS) permit large evaluation units. In 2015, TASs were conducted in Haiti using more stringent criteria for forming evaluation units, resulting in much smaller geographic areas for evaluation. Using simulations, the authors found that, had Haiti followed the existing guidelines and assessed larger geographic areas, many of the areas might have been misclassified and mass drug administration would have been stopped prematurely in some settings. Simulations of mini-TAS, a strategy with smaller power and hence smaller sample size than TAS, resulted in more conservative “passing” and “failing” when implemented in original evaluation units. This research suggests that caution is needed when forming evaluation units for TAS, especially if the prevalence of lymphatic filariasis is not uniform.

现有用于划定传播评估调查（TAS）地理区域的指南允许使用较大的评估单元。2015年，海地在开展TAS时采用了更严格的评估单元划分标准，从而形成了规模远小于常规的评估地理区域。通过模拟研究，作者发现，若海地当时遵循现有指南并对更大的地理区域进行评估，许多区域可能会被错误分类，且在部分场景下群体药物治疗可能会过早终止。迷你TAS（mini-TAS）是一种检验效能低于TAS、因此样本量更小的策略。在原始评估单元中实施迷你TAS的模拟结果显示，其"通过"和"失败"的判定更为保守。该研究表明，在为TAS划分评估单元时需谨慎行事，尤其是当淋巴丝虫病的流行率不均匀时。