Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for the opportunity to review the manuscript ID: vaccines-4441145. This study aimed to assess identify factors associated with respiratory vaccination uptake among older adults living in rural Amazonian communities in Peru.  
 
Comments:  

1. Section Introduction: In a very concise and well-argued manner, the authors emphasized the importance of vaccinating the elderly against respiratory infectious diseases, especially considering the constant increase in the world's population of the elderly. The challenges facing the implementation of vaccination in the vulnerable population of the elderly are particularly pronounced in rural areas. Based on the fact that there are very limited data on the determinants of vaccination coverage against respiratory diseases in the elderly population, the authors set as the goal of this study the investigaton of respiratory vaccination practices and their determinants in rural Amazonian communities in northern Peru.     

- This section should describe the practice of vaccination against respiratory infectious diseases in the elderly population in Peru, including rural Amazonian communities. State the indications, whether influenza/pneumococcal/pertussis vaccination is mandatory or recommended, whether it is paid or free, type of vaccine, etc.
- Provide data on incidence and mortality from respiratory infectious diseases (influenza/pneumococcal disease/pertussis/COVID-19) in the elderly population in Peru, including rural Amazonian communities.     

2. Methods section: Study design, Study setting, Study population, inclusion and exclusion criteria for this study, Variables, Outcomes, Sample size calculation, Statistical analysis, Ethical consideration are described in this section.

Explain what is correct in this paper:
- Whether the claim stated on Lines 80-82 in the Methods section: `Records with missing data in the variables of interest were defined as an exclusion criterion; however, no incomplete records were identified. The final sample included 429 participants.`. 
- Or the claim stated below Table 1 in the Results section: `For the descriptive analysis, some variables might not add up to the final sample size, but in no case did the missing data exceed 10%.`.         

3. Section Results: In this section, all 4 Tables are clear and transparent, with a detailed description in the corresponding text.          
 
4. Section Discussion: In the first paragraph of this section, the authors showed that vaccination coverage in the elderly population in this study was suboptimal, identifying the association of coverage with factors from different categories, including sociodemographic factors, certain geriatric syndromes, and use of health services.
The results of this work are discussed in detail, comprehensively and logically. In the comparison of the results of this work with the results of other studies, relevant current literature was used.   
 
5. The authors have detailed and honestly stated and discussed the limitations of this study, with possibilities for mitigating the aforementioned shortcomings.
Also, the authors correctly pointed out the advantages and strength of this study.  

6. The conclusions are supported in an appropriate way by the results of this study.       

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Overall comments

This manuscript addresses an important public health issue by investigating factors associated with respiratory vaccination uptake among older adults living in rural Amazonian communities in Peru. The study is clinically relevant, particularly given the limited evidence from underserved populations. However, several methodological and reporting issues should be addressed to improve the clarity and scientific rigor of the manuscript.

Major concerns

1. Background and study rationale

As this study focuses on respiratory vaccines (influenza, pneumococcal, COVID-19, and pertussis), the Introduction would benefit from a more comprehensive description of the current vaccination policies and coverage in Peru, particularly among older adults. Please provide the national vaccination recommendations, target age groups, and recent vaccination coverage for these vaccines, as this information is essential for understanding the public health context and the significance of the study.

2. Choice of statistical model

The rationale for using a linear regression model is unclear. The number of respiratory vaccines received ranges only from 0 to 4, representing a discrete count outcome rather than a continuous variable. Please justify the use of linear regression for this outcome or explain why a count regression model (e.g., Poisson or negative binomial regression) was not selected. If linear regression was retained, please clarify whether the model assumptions were assessed and adequately met.

Minor concerns

1. Definition of older adults

The Introduction refers to older adults throughout the manuscript; however, the age criterion used to define this population is not explicitly stated. Please specify the definition of older adults (e.g., age cutoff) in the Introduction.

2. Study population and participant flow

Although the exclusion criteria are described, only the final sample size (n = 429) is reported. Please provide the number of individuals initially assessed for eligibility, the number excluded at each stage, and the reasons for exclusion. A participant flow diagram following the STROBE recommendations would substantially improve the transparency of the study.

3. Terminology

Line 122: The expression "third group" is ambiguous, as it may be interpreted as referring to a patient subgroup rather than a category of variables. Please consider replacing it with "a third category of covariates" or similar wording to improve clarity.

4. Table 4

Please carefully verify the results presented in Table 4. Some prevalence ratio estimates appear inconsistent with their corresponding 95% confidence intervals (e.g., PR = 1.92 with a 95% CI of 1.35–1.61, where the point estimate lies outside the confidence interval). In addition, please review the reported estimates to exclude potential calculation or typographical errors.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Your study has an public health interest given the morbidity, mortality and equity impact.

I suggest that you give more information and comments related to :

1) to which extend this population groups is different from other Peruvian population groups ( i.e. poor urban communities or other isolated population population) in terms of health status, access to services and vaccination coverage.

2) in terms of sampling, you have given exclusion criteria. What is the importance of these exluded people and to which extend your findings and results could have led to different conclusions?

3) could you develop more specific integrated campaign strategies for these population groups in the future ?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The other revisions have been adequately addressed. However, the response regarding the choice of linear regression remains insufficient, as statements that the empirical distribution supported its use and that the model assumptions were verified are not accompanied by any specific diagnostic methods or results. Given that the outcome is a bounded count variable ranging from 0 to 4, please describe how linearity, normality and homoscedasticity of the residuals were assessed, report whether any violations were identified, and clarify whether the fitted values remained within the plausible range; alternatively, a sensitivity analysis using an appropriate count regression model could further support the robustness of the findings.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for your amendments.

Author Response

Thank you for your comments and suggestions. We appreciate your time and thoughtful review of our manuscript.