Acceptance of Booster COVID-19 Vaccine and Its Association with Components of Vaccination Readiness in the General Population: A Cross-Sectional Survey for Starting Booster Dose in Japan

Round 1

Reviewer 1 Report

This is a well written and relevant web-based prospective study on the intention of a Japanese population to be vaccinated with a third dose of a SARS-C0V2 vaccine. This study is surely worth of publication. However, a few comments and request for clarification:

1. It is unclear how the 7.000 subjects contacted were selected. It only states that an Internet research firm was contacted which did the survey. To exclude selection bias the criteria for contact need to be clarified. Also, there might be anyhow a bias as the population are those who have access and use Internet which might be a bias against elderly. This potential bias needs to be discussed. Also, the author should comment why they had a cohort starting with 20 yrs whereas the Japanese booster policy was 18 yrs and above. 

2. It would have been important to analyse if response differed by the vaccine the participants received as priming.

3. Whilst the 7 C's /social norms play an important role in vaccine acceptance, when it comes to boosters one major driver is whether primary vaccination was associated with an adverse event or not. This piece of information is missing and the population should have been stratified into those without AE and those who had an "AE which interfered with daily activities". As these data are probably not available this shortcoming needs to be included in the discussion.

4. There are a few nomenclature which need to be adjusted: "disagree or strongly disagree" is not Hesitancy but Refusal.  The category "not sure"is Hesitancy.

5. Table 2 needs to be reconstructed: the N participants per category is unclear and should be included in an additional column. For example, it is not clear if the 44% males who show acceptance is based on 1.000 males ort on 5.000 males. And it becomes especially problematic when it comes to "area" where the numbers are very misleading.   

6. the authors should discuss if the distribution as shown in table 2 is representative for Japan, ie age distribution, area of living etc. It is not problematic if not representative but this needs to be mentioned in the discussion. 

Author Response

Dear Reviewer 1

 

Thank you for the constructive feedback on our manuscript. We are very grateful to the editors and reviewers for their insightful suggestions and comments. We wish to resubmit a revised draft of our research article for publication in Vaccines, titled “Acceptance of Booster COVID-19 Vaccine and Its Association with Components of Vaccination Readiness in the General Population: A Cross-sectional survey for starting booster dose in Japan” The manuscript ID is vaccines-1773746.

 

We have addressed the comments of the reviewers in the revised manuscript, and all the changes in the revised manuscript have been highlighted. We have included elaborate point-by-point responses to the specific comments of the reviewers. All the authors have read and approved the revised manuscript for submission to Vaccines.

Please see the attachment.

Sincerely,

Mikiko Tokiya,

Author Response File: Author Response.pdf

Reviewer 2 Report

First of all I would like to thank for the opportunity to review this paper. COVID-19 is an ongoing pandemic that has resulted in global health, economic and social crises. Actually, the vaccination campaign is the first method to counteract the COVID-19 pandemic; however, sufficient vaccination coverage is conditioned by the people’s acceptance of these vaccines. In this context, the paper under review is aimed at measuring the intentions for COVID-19 booster vaccination in a not clearly stated population.

The subject under study is certainly important, especially in the historical period we are experiencing. The article presents interesting results but, but it is nevertheless believed that, given the organization of the contents and the description of the same, the manuscript cannot be published in its current form. I would like to encourage authors to consider several issues to be improved.

Title: it can be improved, highlight the object of the study: place, time and person.

Introduction: The authors should make clearer what is the gap in the literature that is filled with this study. The authors must better frame their study within the vast body of literature that addressed the issue of acceptance of the vaccination in the adult population and their level of knowledge concerning COVID-19 in the same period of study (refer to articles with DOI: https://doi.org/10.3390/ijerph182010872). What is the international situation?

Methods: The survey was conducted, in part, using non-standard questions. The use of an unreliable instrument is a serious and irreversible limitation. The fact that a similar questions have been used in previous surveys is not sufficient. A validation process must be performed to evaluate the added questions to standard questionnaires. At least an evaluation of the reliability must be performed and reported. Was a pilot study performed?

The enrolment procedure must be specified. How did the authors choose the way to select the sample? This can represent a great bias origin. How did they avoid the selection bias? The author propose a minimum sample size. But it is not clear the reference population? All Japanese citizen? How large is it? Without the numerical identification of the reference population is not clear the validity of the study. A non-representative sample is by its self a non-sense-survey.

Statistical analysis: I suggest to insert a measure of the magnitude of the effect for the comparisons. Please consider to include effect sizes.

Discussion: I also suggest expanding. Emphasize the contribution of the study to the literature. The discussion must be updated with the comparison and discussion regarding knowledge in the groups of population in the same period, a paragraph should be added with a proper reference (see the above mentioned reference). The Authors should add more practical recommendations for the reader, based on their findings. Also, the section of limitations and future search is also very short, the Authors could elaborate on that.

Author Response

Dear Reviewer 2

Thank you for the constructive feedback on our manuscript. We are very grateful to the editors and reviewers for their insightful suggestions and comments. We wish to resubmit a revised draft of our research article for publication in Vaccines, titled “Acceptance of Booster COVID-19 Vaccine and Its Association with Components of Vaccination Readiness in the General Population: A Cross-sectional survey for starting booster dose in Japan” The manuscript ID is vaccines-1773746.

We have addressed the comments of the reviewers in the revised manuscript, and all the changes in the revised manuscript have been highlighted. We have included elaborate point-by-point responses to the specific comments of the reviewers. All the authors have read and approved the revised manuscript for submission to Vaccines.

Please see the attachment.

Sincerely,
Mikiko Tokiya,

Author Response File: Author Response.pdf

Reviewer 3 Report

Estimated Authors of the paper "Acceptance of Booster COVID-19 Vaccine and Its Association with Components of Vaccination Readiness in the General Japanese Population",

in this questionnaire based study, Tokiya et al. have addressed a significant topic, i.e. the acceptance of COVID-19 as a booster dose in the general Japanese population. The topic is of certain interest for the readers of Vaccines, and highly consistent with the aim of this journal.

The present study was designed though an online survey, and the underlying model (i.e. 7C scale) has been clearly and repetitively proved as both reliable and flexible, as it was validated in a large array of vaccinations and population.

In fact, Authors were able to identify a relatively large share of individuals either largely favorable or favorable to accept a booster dose for COVID-19, stressing that all of the 7C  were reasonably involved in modelling the eventual acceptance of the targeted population.

In fact, I'm recommending the acceptance of this study but some minor issues have to be preventively addressed:

1) please fix the description of the multivariable analysis. As the OR were adjusted by sex, age, marriage, children, underlying disease status, and household income, AOR cannot simply include the aforementioned variables. Either revise the reporting or provide a more extensive explanation. Similarly, please include a detailed description of the multivariable model you did employ in the materials and methods section.

2) when reporting across the main text AOR, please also report their respective 95%CI. 

Author Response

Dear Reviewer 3

Thank you for the constructive feedback on our manuscript. We are very grateful to the editors and reviewers for their insightful suggestions and comments. We wish to resubmit a revised draft of our research article for publication in Vaccines, titled “Acceptance of Booster COVID-19 Vaccine and Its Association with Components of Vaccination Readiness in the General Population: A Cross-sectional survey for starting booster dose in Japan” The manuscript ID is vaccines-1773746.

We have addressed the comments of the reviewers in the revised manuscript, and all the changes in the revised manuscript have been highlighted. We have included elaborate point-by-point responses to the specific comments of the reviewers. All the authors have read and approved the revised manuscript for submission to Vaccines.

Please see the attachment.

Sincerely,
Mikiko Tokiya,

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thank you for accomodating most recommendations, especially to add information on AEs after previous vaccination and impact on booster acceptance. 

Still few commenst: 

1. throughout the manuscript replace "patient" by study participant or similar

2.  Table 2 still needs a revision: the answers should not add up to 100% vertically in one box but horizontally. Example married: there are a total of 2.275 unmarried participants. Of those, 1680 or 73.8% are accepting a boost, 402 or 17.7% are not sure, and 193 or 8.5% are hesitant. Or take age, example 20-28 yrs: the total in this age cohort is 791 subjects. Of those, 521 or 65.9% accept, 22.7% are not sure, and 11.4% are hesitant. You need to do this for each and every line. You also should add an entire column left to the column "Acceptance". This column is to be the N per category line. For example, for males it would be 2.890 and for females 3.282. Pls do this for each line in the table. Another example: for Hokkaido it would read 291. This change in the table as already suggested in the first review but may be was not clear is of critical importance.

3. In lines 29-32 pls modify the display from ie "AOR: 4.02, 95% confidence interval (CI): 3.64-4.45 to : AOR 4.02 (95% CI 3.64-4.45). 

4. I recommend to further clarify the selection bias in the limitations: a selection bias can not be excluded as the universe from where the participants were drawn from belongs to a commercial internet shopping database and thus only includes people with Internet access, and as participation was awarded with points to purchase. (or something similar).

Author Response

Dear Reviewer, 1

Thank you very much for your many comments and your kind guidance.　

Please see the attachment

And the sections of the manuscript that we have revised are highlighted in green.

 

Best regards

Mikiko Tokiya

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper was improved following the suggestions and it is now suitable for publication

Author Response

Dear Reviewer, 2

Thank you very much for your many comments and your kind guidance.　

We reviewed the document for spelling and appropriate grammar and wording. Once again, we performed comprehensive English editing.

The sections of the manuscript that we have revised are highlighted in green.

Best regards

Mikiko Tokiya