Review 3: "How does Treatment Coverage and Proportion Never Treated Influence the Success of Schistosoma Mansoni Elimination as a Public Health Problem by 2030?"

RR:C19 Evidence Scale rating by reviewer:

• Strong. The main study claims are very well-justified by the data and analytic methods used. There is little room for doubt that the study produced has very similar results and conclusions as compared with the hypothetical ideal study. The study’s main claims should be considered conclusive and actionable without reservation.

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Review: The study uses two mathematical models to assess the importance of people never treated on the likelihood of reaching targets for control of schistosomiasis by mass drug administration. The higher the proportion never treated, the less likely targets are reached, or the longer the duration of treatment required. The result is robust to different settings.

This manuscript is a short summary of the results of modeling to quantify the impact of never-treated proportion of a population on the achievement of goals for control of schistosomiasis. It is informative and clear. I have a few suggestions that the authors could consider, but none are essential for publication. As supplementary materials were unavaialabe, I have not been able to review.

Suggestions on the main text are as follows:

1. Abstract, Methods: Please describe the full experimental detail, not just that there are two age intensity profiles (i.e. the dimensions of Table 2).

2. Abstract, Results: Please describe the main results for the different age profiles as well as the baseline prevalence.

3. Results/Discussion: One of the strengths of this work is the use of two separate models. However, they are not compared in the results or mentioned in the discussion – did they agree? What was the value of using two models? Are they similar because they have the same root (Anderson & Medley, 1983).

4. Discussion: Some mention of the causes of NT in the discussion would be more complete. Migration/movement is mentioned as a complication, but there is a literature on why people are NT, which could be pointed at.

5. Discussion: It is not clear how the modeling distributes the NT proportion in terms of age/sex, and how they infect each other. I would expect that the same proportion NT would give different results if randomly distributed through the population compared to all being in the same households/villages. Please expand.
   
   Minor points:

1. Introduction, para 2: The abbreviation “PC” is never used, and as I am not sure that “preventive chemotherapy” is correct (it’s just chemotherapy and doesn’t prevent specially in the treated individual) so I suggest removing. It is not included in the Abbreviations.

2. Table 2: Unless there is an optical illusion in play, there are two shades of grey in the table. Please reduce to one.

3. Funding: The mention of funding to Hollingsworth is unusual given that they are not an author.