-->PONE-D-25-65079-->-->Epidemiology and Seasonal Patterns of Dengue in Muscat Governorate, Oman (2022–2023): A Retrospective Study-->-->PLOS One

Dear Dr. Al-Maskari,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please try to answer to the reviewers' questions in details even if some of them might be shared between two or more. Please explain the specificity of the studied area, the meaning to check in the reference hospital that uncover the acute and more severe cases even if usually most of dengue disease epidemic belongs to large subclinical infection (look at the litterature). Some comment about the statistical analysis deserved to be followed or commented.

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PLOS One

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Additional Editor Comments:

Dear Authors, your article was reviewed by too many individuals, and many of the questions are in double or triple. They are the most important to anwer first. There was also some suggestion in the presentation for the studied area that deserved to be more precisely described. Thus to explain for the reviewer what are the specificity of the muscat governorate compared to the south east coast of Oman. Ie there was no Mousson in this area if I have understood. Moreover the rains level and humidity percentage deserved to be provided during the study period as it is very variable from one year to another.

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Reviewers' comments:

Reviewer's Responses to Questions

-->Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. -->

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Partly

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-->2. Has the statistical analysis been performed appropriately and rigorously? -->

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

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-->3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.-->

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Yes

Reviewer #4: No

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-->4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.-->

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

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-->5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)-->

Reviewer #1: This manuscript addresses an important and timely public health issue in Oman and the Eastern Mediterranean Region. The topic is relevant, the dataset is substantial, and the public health implications are clear. The manuscript is generally well written, intelligible, and presented in standard academic English. The structure is logical, tables and figures are clear, and terminology is appropriate for an international readership. However, there are significant methodological, analytical, and interpretative limitations that must be addressed before the manuscript can be considered for publication. Many of the reported associations appear to reflect health-system or diagnostic practices rather than true epidemiological or environmental drivers.

1. Major Concerns:

a) The study population represents only hospitalized cases, limiting epidemiological inference.

b) Seasonality is analyzed without incorporating climatic or entomological data.

c) The regression outcome (wet vs dry season) is conceptually weak and risks misinterpretation.

• Several statistically significant findings lack biological plausibility.

• Data availability statements are internally inconsistent.

1. The title is accurate but may overstate epidemiological inference given the hospitalized-only population. The abstract clearly summarizes results; however, the conclusions should avoid causal language. Associations with hospital of admission and PCR positivity should be explicitly framed as system-level findings. I suggest to clarify in the title or abstract that findings apply to hospitalized cases only.

2. The introduction is comprehensive but overly long. Several paragraphs repeat regional background information. Key epidemiological concepts are well introduced; however, the rationale for focusing on hospitalized cases should be stated explicitly.

3. Statements on dengue incidence rates in Oman require clearer sourcing and contextualization, particularly given known underreporting.

4. Methods – Study Design and Population. The retrospective design is appropriate for descriptive epidemiology. However, labeling the study as 'analytical' is questionable given the absence of exposure variables. The use of convenience sampling is acceptable but substantially limits generalizability. This limitation should be emphasized earlier and more strongly.

The definition of seasons should be justified with meteorological references rather than convention alone.

5. Methods – Statistical Analysis. The primary analytical concern is the choice of outcome variable (wet vs dry season). Season is not an outcome but a temporal classification. Modeling predictors of seasonality creates a high risk of reverse causation and misinterpretation.

The use of backward elimination may lead to unstable models. Model diagnostics, multicollinearity assessment, and goodness-of-fit statistics are not reported.

It is unclear whether interaction terms (e.g., hospital × season) were assessed.

6. Results

Results are clearly presented and tables are generally well structured. However, mortality of 3.8% is relatively high and deserves deeper stratified analysis. The dominance of Seeb Wilayat likely reflects catchment population size, which is not adjusted for. PCR positivity being higher in the wet season likely reflects timing of presentation and testing practices, not increased transmission.

7. The discussion appropriately contextualizes findings within regional literature. However, several interpretations overreach the data: Associations with hospital admission should not be interpreted as epidemiological risk factors. The discussion of autoimmune conditions is speculative and unsupported by the dataset.

The authors appropriately acknowledge many limitations, but these should be integrated into the interpretation of results rather than listed separately.

8. Key limitations are acknowledged but underemphasized:

• Exclusion of non-hospitalized cases.

• Absence of climatic, entomological, and serotype data.

• Potential referral and diagnostic bias.

These limitations substantially restrict causal and predictive conclusions.

9. The conclusions should be revised to avoid implying causality. Recommendations for vector control and preparedness are appropriate but should be framed as supported by broader evidence, not solely this study. The conclusions are partially overextended. Several associations—particularly those related to hospital of admission and PCR positivity as predictors of wet-season dengue—reflect health-system, referral, and diagnostic practices rather than intrinsic epidemiological or environmental drivers. These findings do not establish causal or biological relationships and should be interpreted more cautiously.

10. In addition, because the study includes only hospitalized cases, the conclusions cannot be generalized to dengue transmission dynamics at the population level. With appropriate reframing of conclusions to emphasize descriptive and system-level findings, the data would adequately support the revised conclusions.

Reviewer #2: Overall Assessment (Reviewer Comment)

General Comment:

This manuscript addresses an important and timely public health issue “Dengue Epidemiology and Seasonality in Muscat Governorate, Oman” using a relatively large, well-validated hospital-based dataset. The study is clearly written, methodologically sound, and adds local evidence to a region with limited published dengue data. However, several conceptual, methodological, and interpretative issues need clarification to strengthen scientific rigor, internal consistency, and generalizability. Most concerns relate to season definitions, interpretation of regression findings, representativeness of hospitalized cases, and overstatement of causal inferences.

FINAL REVIEWER VERDICT

Recommendation: Major Revision

MAJOR COMMENTS (Require Substantive Revision)

1. Inconsistency and Conceptual Ambiguity in Season Definition

The manuscript defines the dry season as May–October and the wet season as November–April (Methods, line 187). However, peak dengue cases are repeatedly described as occurring in April–May, which straddles both seasons. This creates conceptual ambiguity and weakens the interpretation of “wet-season dengue risk.”

Clarify the seasonal categorization using meteorological data or authoritative local climate references.

Consider sensitivity analysis using alternative seasonal cutoffs (e.g., pre-monsoon, monsoon, post-monsoon).

2. Interpretation of Logistic Regression Findings

The multivariable analysis identifies hospital of admission and PCR positivity as predictors of wet-season dengue. However, these variables are health-system and diagnostic factors, not epidemiological risk factors for dengue transmission.

Concern:

The manuscript occasionally implies epidemiological or environmental significance, which may mislead readers.

Therefore, reframe these findings consistently as healthcare system–related associations, not determinants of transmission.

Clarify that PCR positivity likely reflects testing timing and clinical suspicion rather than increased incidence.

Avoid causal language when discussing adjusted odds ratios.

3. Limited External Validity and Selection Bias

The study includes only hospitalized patients from two tertiary hospitals, representing moderate-to-severe cases. This substantially limits generalizability to community level dengue epidemiology.

Recommendation:

Emphasize throughout (Abstract, Discussion, Conclusion) that findings apply primarily to hospitalized dengue cases.

Avoid statements suggesting population-level dengue risk or overall incidence patterns without outpatient or community data.

4. Mortality Rate Needs Contextualization

The reported mortality rate (3.8%) appears high compared to many dengue-endemic settings.

Recommendation:

Provide here contextual comparison with regional or hospital-based mortality rates.

Clarify whether deaths were directly attributable to dengue or involved significant comorbidities.

Consider reporting case fatality rate stratified by severity.

5. Overextension of Public Health Implications

While recommendations for vector control and preparedness are appropriate, the study lacks direct entomological or climatic data, limiting the strength of policy implications.

Recommendation:

Temper conclusions to align with the study’s descriptive and hospital-based nature.

Explicitly state that vector control recommendations are supported by existing literature, not direct measurements from this study.

MINOR COMMENTS (Editorial / Clarity Issues)

1. Title

The title contains a typographical error: “Retrospective Stud” → “Retrospective Study”.

Also consider specifying hospitalized cases for accuracy.

Suggested Revision:

“Epidemiology and Seasonal Patterns of Hospitalized Dengue Fever Cases in Muscat Governorate, Oman (2022–2023): A Retrospective Study”

2. Abstract – Results

Percentages are sometimes presented without clear denominators (e.g., Wilayat distribution). Consider briefly clarifying the population base.

3. Abstract – Conclusions

The phrase “higher wet-season risk” may be misleading given that total cases were higher in the dry season.

Suggested Revision:

Replace with: “distinct seasonal and geographic clustering” rather than “higher wet-season risk.”

4. Methods – Sampling Technique

The justification for convenience sampling is acceptable, but the phrase “reduce selection bias” is inaccurate.

Suggested Revision:

Replace with: “to maximize sample size, acknowledging potential selection bias inherent to retrospective hospital-based data.”

5. Tables

Tables 2 and 3 contain some inconsistencies in spacing and labeling (e.g., “Auto immune” vs. “Autoimmune”). Ensure uniform terminology and formatting across all tables.

6. Figures

Figures are referenced appropriately, but captions could be more descriptive, particularly Figure 1, by stating whether counts represent admissions or cases.

SECTION-BY-SECTION ANNOTATED COMMENTS

Introduction

The introduction is comprehensive and well referenced but could be more concise. Some global statistics (e.g., global burden, CDC estimates) are repeated or overly detailed relative to the local study aim.

Suggestion:

Streamline global burden discussion and sharpen the knowledge gap specific to Oman.

Materials and Methods

Data validation procedures are well described and strengthen credibility. However, absence of meteorological variables limits seasonal inference.

Suggestion: Explicitly state that seasonality is inferred indirectly.

Results

Results are clearly presented and tables are informative. However, p-values are sometimes emphasized without sufficient discussion of clinical relevance.

Discussion

The discussion is well structured and thoughtfully interprets findings. Strength lies in distinguishing health system effects from epidemiological drivers.

This distinction should be made more consistently throughout.

References

Need reference formatting according to journal guidelines. Add more updated references of 2026.

Limitations

Limitations are appropriately acknowledged but could include:

1. Misclassification bias due to season definition

2. Potential referral bias between hospitals

3. Conclusion

Comment:

The conclusion is balanced but could be tightened to avoid restating results already discussed.

FINAL REVIEWER VERDICT

Recommendation: Major Revision

The manuscript is publishable after addressing conceptual clarity on seasonality, refining interpretation of regression findings, and moderating causal and policy claims.

Reviewer #3: The overall picture of the article seems good and results are written in a manner which in understandable, but the area where the figures number 1, 2 and 3 has to be mentioned, didn't show the figures. I recommend to see it once, otherwise, overall it is good and well explained.

Reviewer #4: The manuscript places disproportionate emphasis on geographic, climatic, and economic context, while providing relatively limited depth on dengue disease characteristics, transmission dynamics, and preventive or control measures. A stronger focus on the disease itself—particularly public health implications, vector control strategies, and clinical relevance—is needed.

It is also unclear whether all reported cases represent hospitalized patients, patients treated at home, or cases managed under different clinical circumstances. This distinction is critical and should be explicitly clarified in the Methods and reflected consistently throughout the Results and Discussion.

The data presented reflect a highly localized analysis limited to one or two hospitals, which substantially restricts the epidemiological generalizability of the findings. At a minimum, the study should aim to cover a broader administrative unit (e.g., province or governorate-wide surveillance data) rather than a single-hospital or narrow hospital-based dataset.

Additionally, demographic characteristics of participants should be more comprehensively described using appropriate statistical summaries (e.g., age distribution, sex stratification, nationality, comorbidities) and clearly integrated into the analysis. The current presentation lacks sufficient depth in demographic and risk-factor profiling.

Overall, the manuscript would require a major revision, including expansion of the dataset to include more cases, additional hospitals, and a broader range of epidemiological and statistical variables. Without these improvements, the study remains limited in scope and impact.

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Reviewer #1: Yes: Edmond Edmond

Reviewer #2: No

Reviewer #3: Yes: Ayesha Irfan

Reviewer #4: Yes: M. Irfan-Maqsood

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Attachments

Attachment

Submitted filename: Reviewers Comments PONE-D-25-65079.docx

Epidemiology and seasonal patterns of hospitalized dengue cases in Muscat Governorate, Oman (2022-2023): A retrospective study

PONE-D-25-65079R1

Dear Dr. Al-Maskari,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Pierre Roques, Ph.D.

Academic Editor

PLOS One

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

-->Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.-->

Reviewer #1: All comments have been addressed

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-->2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. -->

Reviewer #1: Yes

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-->3. Has the statistical analysis been performed appropriately and rigorously? -->

Reviewer #1: Yes

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-->4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.-->

Reviewer #1: Yes

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-->5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.-->

Reviewer #1: Yes

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-->6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)-->

Reviewer #1: Dear editor

As I see, the authors are responded points by points to all reviewers commnet.

The manuscript addresses an important and timely topic with clear relevance to global health, particularly in the context of increasing antimicrobial resistance and the burden of infectious diseases in both community and hospital settings. The topic is appropriate for the journal’s scope and has potential clinical and public health implications.

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Reviewer #1: No

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