Dear Dr Maheu-Giroux,

Thank you for submitting your manuscript entitled "HIV prevalence, population sizes, and HIV prevention among men who paid for sex in sub-Saharan Africa: a meta-analysis of 82 population-based surveys (2000-2020)" for consideration by PLOS Medicine.

Your manuscript has now been evaluated by the PLOS Medicine editorial staff and I am writing to let you know that we would like to send your submission out for external peer review.

However, before we can send your manuscript to reviewers, we need you to complete your submission by providing the metadata that is required for full assessment. To this end, please login to Editorial Manager where you will find the paper in the 'Submissions Needing Revisions' folder on your homepage. Please click 'Revise Submission' from the Action Links and complete all additional questions in the submission questionnaire.

Please re-submit your manuscript within two working days, i.e. by Jun 17 2021 11:59PM.

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Feel free to email us at plosmedicine@plos.org if you have any queries relating to your submission.

Kind regards,

Beryne Odeny

Associate Editor

PLOS Medicine

Dear Dr. Maheu-Giroux,

Thank you very much for submitting your manuscript "HIV prevalence, population sizes, and HIV prevention among men who paid for sex in sub-Saharan Africa: a meta-analysis of 82 population-based surveys (2000-2020)" (PMEDICINE-D-21-02581R1) for consideration at PLOS Medicine.

Your paper was discussed among the editors and sent to independent reviewers, including a statistical reviewer. The reviews are appended at the bottom of this email and any accompanying reviewer attachments can be seen via the link below:

[LINK]

In light of these reviews, we will not be able to accept the manuscript for publication in the journal in its current form, but we would like to invite you to submit a revised version that addresses the reviewers' and editors' comments fully. You will appreciate that we cannot make a decision about publication until we have seen the revised manuscript and your response, and we expect to seek re-review by one or more of the reviewers.

In revising the manuscript for further consideration, your revisions should address the specific points made by each reviewer and the editors. Please also check the guidelines for revised papers at http://journals.plos.org/plosmedicine/s/revising-your-manuscript for any that apply to your paper. In your rebuttal letter you should indicate your response to the reviewers' and editors' comments, the changes you have made in the manuscript, and include either an excerpt of the revised text or the location (eg: page and line number) where each change can be found. Please submit a clean version of the paper as the main article file; a version with changes marked should be uploaded as a marked up manuscript.

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Please let me know if you have any questions, and we look forward to receiving your revised manuscript.

Sincerely,

Richard Turner PhD, for Beryne Odeny

Senior editor, PLOS Medicine

rturner@plos.org

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Comments from the reviewers:

*** Reviewer #1:

[See attachment]

Michael Dewey

*** Reviewer #2:

This is an excellent study that is adding to the small number of evidence on the clients of sex workers.

However, the authors did not address many of the issues they have highlighted. Using your critical minds and wealth of knowledge, what recommendations/ suggestions to you have for the public health authorities, the FSWs or to even clients of sex workers?

It would have been interesting to know:

-their policy recommendations for public health authorities?

- any recommendations for public health authorities using sex workers are index clients?

-what prevention approaches to tackle the high HIV prevalence in Western Africa versus the Southern?

-What services should be added in the health centers to reach out to clients of sex workers?

As a public health expert, this study is equality interesting to me as an evidence paper and as a study to guide policy recommendations. Unfortunately, the latter is missing.

*** Reviewer #3:

The study is very useful especially now that HIV prevalence remain stable in some countries in Sub Saharan Africa (SSA). It is appreciated to see that the authors have focused on a specific population group (Men) which provides more specific information regarding their vulnerability to HIV infections through pay for sex.

However, there are a few aspects that need to be incorporated:

- it is important to clarify starting with the abstract on which countries in SSA Africa the data was analyzed

- It is not clear on whether men who were involved in the study were heterosexual or not, I think the sexual orientation need to be stipulated clearly

- It is also important that the authors clarify in the abstract section about whether men paid for sex with women or with men? this is not clearly stated in the abstract

- An implication of the study on access to treatment will be useful

- Some additional lines that would contribute to the existing paradox that women also pay for sex (Mtenga et al. AIDS Res Ther (2018) 15:12 https://doi.org/10.1186/s12981-018-0199-6), will make a an important argument.

*** Reviewer #4:

I would like to appreciate the authors for the great work. Conceptually, I found the paper very coherent and structured in a well thought out fashion. With pleasure, I would like to provide a few suggestions on the manuscript.

First, motivation of the authors to do the paper has been mentioned as "less attention" drawn to interventions aimed at targeting clients of sex workers. However, this justification could not tell the convincing reason for doing the study as the study focuses on HIV epidemiology, including other related issues, among these groups. If you find that interventions on men paying for sex are given less attention, then the study should have been on finding reason for "why this happens". But now, your study is on HIV burden, HIV testing, condom use etc, and the driver for carrying out this should have been explained differently like for instance, limited knowledge base on this area. Simply put, linking a study focused on HIV burden with a justification using a statement like inattention to prevention [of HIV among those groups] did not work here. Interventions might not be given attention but as the same time HIV burden can be known. So, this leads us to that, there might be many other important factors that potentially prevent policy makers and intervention designers from drawing attention to interventions, and lack of knowledge on HIV epidemiology [the other issues this study has addressed] may still NOT be one of the factors.

So, I suggest that it would be highly useful to succinctly explicate the direct contribution of the paper towards reducing men running into the paid sex practice as well as to our knowledge base on this area.

Second, the selection process of the papers lacks some clarity. How did the authors restrict surveys between 2010-2020, for instance. It is also good to use PRIMSA adopted to the IPD, Individual Participant Data meta-analysis.

Third, the chosen of the random effect model was not justified; why not fixed effect model rather. Give reason. I found the I-squared statistics to be extremely high, suggesting considerable between-study variation in terms of the variables you studied. Given this variability, do you think producing a single overall estimate through pooling is a good practice, as the papers are too different already. Meta-analysists often try fitting meta-regression to explain the variation; in this study, meta-regression could have been done better by including more confounding variables in the model to get unbiased results. Also, under variables, make it clear whether all of these are outcome variables, and mention your independent variables, if any.

Fourth, of the three design elements of a complex design study like DHS, the authors take into account only clustering and unequal probability of selection, via, weighting. However, stratification is missing, and failing to take this problem into account would result in estimation of standard errors that are biased. DHS experts highly recommend researchers to make account of all the three design elements of complex designs like DHS. I would see as a big limitation of the paper as your confidence intervals are likely to be biased.

Finally, these days, countries are moving towards ensuring health equality within their population. International agreements like SDG calls for equity; that means, while the time is to look at health outcomes between different population groups within a country, your study was about aggregating country-level information into a regional level. How do you see the implication of the paper for the wellbeing of different segments of population in each individual country in light of SDG?

Within country inequality analysis of HIV prevalence among men paying for sex is very important to understand who these group of men are and why they are being engaged in the activity. Because, all men in this high-risk behavior are not homogenous population group and how their engagement in this risky sexual behavior is affected by contexts they live in remains a huge research question that could substantially contribute towards the SDG related with HIV. To the contrary, you did aggregate based analysis. Can explain more on this.

Regards,

Gebretsadik Shibre

***

Any attachments provided with reviews can be seen via the following link:

[LINK]

Attachments

Attachment

Submitted filename: hodgins.pdf

Dear Dr. Maheu-Giroux,

Thank you very much for re-submitting your manuscript "HIV prevalence, population sizes, and HIV prevention among men who paid for sex in sub-Saharan Africa (2000-2020): a meta-analysis of 87 population-based surveys" (PMEDICINE-D-21-02581R2) for review by PLOS Medicine.

I have discussed the paper with my colleagues and the academic editor and it was also seen again by one reviewer. I am pleased to say that provided the remaining editorial and production issues are dealt with we are planning to accept the paper for publication in the journal.

The remaining issues that need to be addressed are listed at the end of this email. Any accompanying reviewer attachments can be seen via the link below. Please take these into account before resubmitting your manuscript:

[LINK]

***Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.***

In revising the manuscript for further consideration here, please ensure you address the specific points made by each reviewer and the editors. In your rebuttal letter you should indicate your response to the reviewers' and editors' comments and the changes you have made in the manuscript. Please submit a clean version of the paper as the main article file. A version with changes marked must also be uploaded as a marked up manuscript file.

Please also check the guidelines for revised papers at http://journals.plos.org/plosmedicine/s/revising-your-manuscript for any that apply to your paper. If you haven't already, we ask that you provide a short, non-technical Author Summary of your research to make findings accessible to a wide audience that includes both scientists and non-scientists. The Author Summary should immediately follow the Abstract in your revised manuscript. This text is subject to editorial change and should be distinct from the scientific abstract.

We expect to receive your revised manuscript within 1 week. Please email us (plosmedicine@plos.org) if you have any questions or concerns.

We ask every co-author listed on the manuscript to fill in a contributing author statement. If any of the co-authors have not filled in the statement, we will remind them to do so when the paper is revised. If all statements are not completed in a timely fashion this could hold up the re-review process. Should there be a problem getting one of your co-authors to fill in a statement we will be in contact. YOU MUST NOT ADD OR REMOVE AUTHORS UNLESS YOU HAVE ALERTED THE EDITOR HANDLING THE MANUSCRIPT TO THE CHANGE AND THEY SPECIFICALLY HAVE AGREED TO IT.

Please ensure that the paper adheres to the PLOS Data Availability Policy (see http://journals.plos.org/plosmedicine/s/data-availability), which requires that all data underlying the study's findings be provided in a repository or as Supporting Information. For data residing with a third party, authors are required to provide instructions with contact information for obtaining the data. PLOS journals do not allow statements supported by "data not shown" or "unpublished results." For such statements, authors must provide supporting data or cite public sources that include it.

To enhance the reproducibility of your results, we recommend that you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. Additionally, PLOS ONE offers an option to publish peer-reviewed clinical study protocols. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript.

Please note, when your manuscript is accepted, an uncorrected proof of your manuscript will be published online ahead of the final version, unless you've already opted out via the online submission form. If, for any reason, you do not want an earlier version of your manuscript published online or are unsure if you have already indicated as such, please let the journal staff know immediately at plosmedicine@plos.org.

If you have any questions in the meantime, please contact me or the journal staff on plosmedicine@plos.org.  

We look forward to receiving the revised manuscript by Oct 19 2021 11:59PM.   

Sincerely,

Beryne Odeny,

PLOS Medicine

plosmedicine.org

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Requests from Editors:

1. Please define abbreviations in tables e.g. PLHIV.

2. Please indicate in the figure caption the meaning of the bars and whiskers in Figure S4.

3. Please provide your MOOSE checklist and complete it with paragraph numbers per section (e.g. "Methods, paragraph 1").

4. The survey flowchart can be included in the main paper.

5. To help us extend the reach of your research, please provide any Twitter handle(s) that would be appropriate to tag, including your own, your coauthors’, your institution, funder, or lab.

Comments from the Academic Editor:

I would ask the authors to comment in a bit more detail the issue of 'paying' for sex as opposed to 'gifts etc'. There are some sentences relating to that in the limitation, which are fine, but for me the issue would be the overall rather low prevalence of men paying for sex (only 8% overall), which is lower than would be anticipated in terms of 'bought' sex (irrespective of whether it was money or gifts), especially in South/southern Africa. The authors may like to comment on the prevalence of paying for sex, by region. In South/southern Africa the concept of 'sugar daddy' is relatively common (and may involve more than one recipient at a time), but usually does not involve money directly and it is likely that this would not have been reported as 'paying for sex with a sex worker'. I appreciate that the authors are limited by the data available but could still comment on that in the limitations, and the generalisability of the conclusion.

Comments from Reviewers:

Reviewer #1: The authors have addressed all my points

Michael Dewey

Any attachments provided with reviews can be seen via the following link:

[LINK]

Dear Dr Maheu-Giroux, 

On behalf of my colleagues and the Academic Editor, Dr. Marie-Louise Newell, I am pleased to inform you that we have agreed to publish your manuscript "HIV prevalence, population sizes, and HIV prevention among men who paid for sex in sub-Saharan Africa (2000-2020): a meta-analysis of 87 population-based surveys" (PMEDICINE-D-21-02581R3) in PLOS Medicine.

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To enhance the reproducibility of your results, we recommend that you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. Additionally, PLOS ONE offers an option to publish peer-reviewed clinical study protocols. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols

Thank you again for submitting to PLOS Medicine. We look forward to publishing your paper. 

Sincerely, 

Beryne Odeny 

PLOS Medicine