Dear Dr Arkell

Thank you very much for submitting your manuscript "Field evaluation of rapid diagnostic tests to determine dengue serostatus in Timor-Leste" for consideration at PLOS Neglected Tropical Diseases. As with all papers reviewed by the journal, your manuscript was reviewed by members of the editorial board and by several independent reviewers. The reviewers appreciated the attention to an important topic. Based on the reviews, we are likely to accept this manuscript for publication, providing that you modify the manuscript according to the review recommendations.

Please prepare and submit your revised manuscript within 30 days. If you anticipate any delay, please let us know the expected resubmission date by replying to this email.

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[1] A letter containing a detailed list of your responses to all review comments, and a description of the changes you have made in the manuscript.

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[2] Two versions of the revised manuscript: one with either highlights or tracked changes denoting where the text has been changed; the other a clean version (uploaded as the manuscript file).

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Thank you again for your submission to our journal. We hope that our editorial process has been constructive so far, and we welcome your feedback at any time. Please don't hesitate to contact us if you have any questions or comments.

Sincerely,

Renata Rosito Tonelli, PhD

Academic Editor

PLOS Neglected Tropical Diseases

Elvina Viennet

Section Editor

PLOS Neglected Tropical Diseases

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Reviewer's Responses to Questions

Key Review Criteria Required for Acceptance?

As you describe the new analyses required for acceptance, please consider the following:

Methods

-Are the objectives of the study clearly articulated with a clear testable hypothesis stated?

-Is the study design appropriate to address the stated objectives?

-Is the population clearly described and appropriate for the hypothesis being tested?

-Is the sample size sufficient to ensure adequate power to address the hypothesis being tested?

-Were correct statistical analysis used to support conclusions?

-Are there concerns about ethical or regulatory requirements being met?

Reviewer #1: Yes

Reviewer #2: This manuscript describes a study to assess the performance of two rapid diagnostic tests (RDTs) to determine dengue serostatus for pre-vaccination screening under field and laboratory conditions in Timor-Leste. The RDTs were performed using whole blood collected from 406 participants, of whom 217 were children. The results were compared to serum samples from the same individuals and tested at the National Health Laboratory using an enzyme-linked immunosorbent assay (ELISA) on serum samples as the comparator. The authors found that the RDTs had low sensitivity which can be improved by using serum and by extending the window for reading the results.

This is a well written paper on a topic that is critically important for the deployment of the only approved dengue vaccine, that can save lives. The study objectives are clearly stated, the study was well designed and the methods appropriate for the study objectives.

There are no ethical or regulatory issues.

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Results

-Does the analysis presented match the analysis plan?

-Are the results clearly and completely presented?

-Are the figures (Tables, Images) of sufficient quality for clarity?

Reviewer #1: Yes

Reviewer #2: The results are clearly presented in tables that are easy to understand and interpret and figures that are good quality.

As the interpretation of RDT results are subjective, the authors should previde details on training of field staff to perform the tests and whether external quality assessment was carried out to ensure proficiency of staff in performing the tests and interpreting the test results.

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Conclusions

-Are the conclusions supported by the data presented?

-Are the limitations of analysis clearly described?

-Do the authors discuss how these data can be helpful to advance our understanding of the topic under study?

-Is public health relevance addressed?

Reviewer #1: Yes

Reviewer #2: The conclusions are supported by the data but there are a few points that should be discussed in more detail:

1. Reference standard: As there is no reference materials for determining dengue seropositivity, the choice of the assay as the comparator clearly affects the test performance. As shown in Table 3, previous studies use different reference standards, the authors should discuss the different reference standards used in previous studies and how they may affect the study results.

2. Discussion: It is well known that IgG antibody responses to different flaviviruses are known to be cross-reactive. The authors should discuss the implications of false positive and false negative results from the use of the RDTs to determine dengue serostatus.

3. The WHO Strategic Advisory Group of Experts (SAGE) on Immunization issued recommendations in April 2016 to introduce the dengue vaccine (Dengvaxia®) in geographical settings (national or subnational) with high endemicity only, as indicated by seroprevalence of >70% in the age group targeted for vaccination. The findings from this study population showed seropositivity rates in excess of 85%, the authors should discuss whether there is still a need for Timor Leste to conduct pre-screening for vaccine introduction.

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Editorial and Data Presentation Modifications?

Use this section for editorial suggestions as well as relatively minor modifications of existing data that would enhance clarity. If the only modifications needed are minor and/or editorial, you may wish to recommend “Minor Revision” or “Accept”.

Reviewer #1: Minor Revision

Reviewer #2: See above

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Summary and General Comments

Use this section to provide overall comments, discuss strengths/weaknesses of the study, novelty, significance, general execution and scholarship. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. If requesting major revision, please articulate the new experiments that are needed.

Reviewer #1: (No Response)

Reviewer #2: The evaluation of the performance of dengue RDTs to determine dengue serostatus is not new but the data on possible reasons for low sensitivity and how to improve it are useful.

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Reviewer #1: Yes: Dr Joseph Biggs

Reviewer #2: No

Figure Files:

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References

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. If you need to cite a retracted article, indicate the article's retracted status in the References list and also include a citation and full reference for the retraction notice.

Attachments

Attachment

Submitted filename: Reviewer_comments_JB.docx

Dear Dr Ankel

We are pleased to inform you that your manuscript 'Field evaluation of rapid diagnostic tests to determine dengue serostatus in Timor-Leste' has been provisionally accepted for publication in PLOS Neglected Tropical Diseases.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow up email. A member of our team will be in touch with a set of requests.

Please note that your manuscript will not be scheduled for publication until you have made the required changes, so a swift response is appreciated.

IMPORTANT: The editorial review process is now complete. PLOS will only permit corrections to spelling, formatting or significant scientific errors from this point onwards. Requests for major changes, or any which affect the scientific understanding of your work, will cause delays to the publication date of your manuscript.

Should you, your institution's press office or the journal office choose to press release your paper, you will automatically be opted out of early publication. We ask that you notify us now if you or your institution is planning to press release the article. All press must be co-ordinated with PLOS.

Thank you again for supporting Open Access publishing; we are looking forward to publishing your work in PLOS Neglected Tropical Diseases.

Best regards,

Renata Rosito Tonelli, PhD

Academic Editor

PLOS Neglected Tropical Diseases

Elvina Viennet

Section Editor

PLOS Neglected Tropical Diseases

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