Clinical, anamnestic, and sociodemographic predictors of positive SARS-CoV-2 testing in children: A cross sectional study in a tertiary hospital in Italy

Benedetta Armocida; Giulia Zamagni; Elena Magni; Lorenzo Monasta; Manola Comar; Nunzia Zanotta; Carolina Cason; Giorgia Argentini; Marianela Urriza; Andrea Cassone; Fulvia Vascotto; Roberto Buzzetti; Egidio Barbi; Massimo Del Pin; Paola Pani; Alessandra Knowles; Claudia Carletti; Federica Concina; Mariarosa Milinco; Luca Ronfani

doi:10.1371/journal.pone.0262923

Peer Review History

Original SubmissionJuly 26, 2021
18 Aug 2021 Decision Letter - Robert Jeenchen Chen, Editor PONE-D-21-24181 Clinical, anamnestic, and sociodemographic predictors of positive SARS-CoV-2 testing in children: a cross sectional study in a tertiary hospital in Italy PLOS ONE Dear Dr. Ronfani, 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 address the issues and revise accordingly. Please submit your revised manuscript by Oct 02 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Robert Jeenchen Chen, MD, MPH Academic Editor PLOS ONE Journal Requirements: When submitting your revision, we need you to address these additional requirements. 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. You indicated that you had ethical approval for your study. In your Methods section, please ensure you have also stated whether you obtained consent from parents or guardians of the minors included in the study or whether the research ethics committee or IRB specifically waived the need for their consent. [Note: HTML markup is below. Please do not edit.] 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: Partly ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ****** 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: No Reviewer #2: Yes ****** 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 ****** 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: The study is well written and the analyses well performed. However, there is a significant basic mistake that does not allow to give much significance to this study. In particular, a single swab performed in the emergency department without information on what happened after discharge has really no sense to me. How can you exclude that you had a false positive result? For example, more than 200 children from the "negative" group had known contacts. Also, a number of children from the negative group had anosmia and ageusia, which you itself define as a predictive symtpoms. Importantly, these symtpoms are very unusual in other diseases. As a proof that the study, although well written and analysed, has low significance, you define that a very common and usual presentation of children in the ED can be predictive of covid. However, we know that so many children can have mild or asymptomatic disease. I am very very sorry to see that you did a huge effort in this analyses, but really the hypothesis behind the design of this study has a very doubtful significance. You should use these data to make a new one, doing f-up swabs as a minimum, or interview of parents to understand if further swabs have been done and the results to see how many of them are true negative. For example, a preprint from UK recenlty found that 1 out of 3 students had IgG positive (!!) confirming that the virus circulates much more than expected. And I am quite sure that among the negative, particularly those with known conttacts and with anosmia/ageusia, you missed several cases. Reviewer #2: In the manuscript authored by Benedetta Armocida et al, authors summarize clinical, anamnestic, and sociodemographic characteristics of children affected or not by Sars Cov-2 in a frame period between September 20th and December 23rd 2020. A major concearn is that authors provided a study that is more descriptive then predictive, as stated from authors. This is a critical point. No follow up is present. ROC curve is computed between 127 positive vs 1357 negative. Are these groups comparable? It is not clear to the reader if authors suggest NOT to perform Sars-Cov2 diagnostic test in children presenting rhinorrhoea, sore throat,or diarrhoea. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0262923.r001
Revision 1
26 Oct 2021 Author Response PONE-D-21-24181 Clinical, anamnestic, and sociodemographic predictors of positive SARS-CoV-2 testing in children: a cross sectional study in a tertiary hospital in Italy 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: The study is well written and the analyses well performed. *Thank you for your appreciation. However, there is a significant basic mistake that does not allow to give much significance to this study. In particular, a single swab performed in the emergency department without information on what happened after discharge has really no sense to me. Thank you for your comment. At that time, the general process after a positive swab envisaged the activation of quarantine and a swab at two weeks by the Department of Prevention. Thus, a follow up (control) swab was always performed, but these follow up swabs could have been performed in other health services, not necessary in our Institute. Moreover, the aim of this study was to identify clinical, anamnestic, and sociodemographic characteristics associated with a positive swab for SARS-CoV-2 in a population of children, hence we aimed at investigating a real life, pragmatic approach in order to try to add some clinical hints for clinicians. Additionally, the swabs were performed in an outpatient clinic, as mentioned in the manuscript, not in an emergency department, and we aimed at investigating the symptoms presented at the time of the swab to observe if specific symptoms could be predictive of testing positivity, thus the follow up swab would have added, in our opinion, not significant information to the aim of the study. How can you exclude that you had a false positive result? For example, more than 200 children from the "negative" group had known contacts. Also, a number of children from the negative group had anosmia and ageusia, which you itself define as a predictive symptoms. Importantly, these symptoms are very unusual in other diseases. As a proof that the study, although well written and analysed, has low significance, you define that a very common and usual presentation of children in the ED can be predictive of covid. However, we know that so many children can have mild or asymptomatic disease. Thank you for your comment. The sensitivity and specificity of the RT-PCR nasopharyngeal swab to detect SARS-CoV-2 declared by the manufacturer are very high (about 100%), so the possibility to have a false positive or negative can be considered pretty low, as also showed in the literature (1). Moreover, regarding the false positives, the swab and kits used for the analysis are certified to identify 3 different genes for all variants that are circulating to date. For each swab the quantity and quality of the material taken was checked, controlling that it was sufficient to highlight up to 5 copies of the virus (lower limit of the test). In case of a doubtful result (eg 2 out of 3 genes positive) the patient was asked to perform again the swab, thus the possibility to have false positives/negatives is very remote. This further information has been included in the manuscript in the section Laboratory methods. About the lost among the cases tested negative possible positive SARS-CoV-2 might be realistic, we observed the trend on another study we conducted on serology, but the aim of this paper was not to demonstrate the circulation of the virus. Furthermore, we do agree that the child can have been asymptomatic or mild, but firstly at that time of the pandemic all children also very slight symptoms were tested, and secondly this study explicitly included only children with symptoms to provide a predictive score to identify children at risk of COVID-19, we were not aiming at identifying all children with a positivity to SARS-CoV-2. We also would like to thank you also for the comment on anosmia and ageusia. Although the symptoms are quite specific, those are not exclusive of COVID-19, but they might have other causes (such as allergies, other viral upper respiratory tract infections, seasonality) (2-3). Thus, those negatives presenting anosmia or ageusia might not be per se false negatives. Furthermore, also other studies reported anosmia and ageusia both in positive and negative cases, but they are more common among positives (3-5), this information has been inserted in the discussion. Finally, as we mentioned in our limits families were directly providing information, and some symptoms might have been misinterpreted, and anosmia and ageusia might be one of these considering the difficulty in detecting such symptoms in children. 1. Floriano I, Silvinato A, Bernardo WM, Reis JC, Soledade G. Accuracy of the Polymerase Chain Reaction (PCR) test in the diagnosis of acute respiratory syndrome due to coronavirus: a systematic review and meta-analysis. Rev Assoc Med Bras (1992). 2020 Jul;66(7):880-888. doi: 10.1590/1806-9282.66.7.880. Epub 2020 Aug 24. PMID: 32844930. 2. Pierron D, Pereda-Loth V, Mantel M, Moranges M, Bignon E, Alva O, Kabous J, Heiske M, Pacalon J, David R, Dinnella C, Spinelli S, Monteleone E, Farruggia MC, Cooper KW, Sell EA, Thomas-Danguin T, Bakke AJ, Parma V, Hayes JE, Letellier T, Ferdenzi C, Golebiowski J, Bensafi M. Smell and taste changes are early indicators of the COVID-19 pandemic and political decision effectiveness. Nat Commun. 2020 Oct 14;11(1):5152. doi: 10.1038/s41467-020-18963-y. PMID: 33056983; PMCID: PMC7560893. 3. Haehner A, Draf J, Dräger S, de With K, Hummel T. Predictive Value of Sudden Olfactory Loss in the Diagnosis of COVID-19. ORL J Otorhinolaryngol Relat Spec. 2020;82(4):175-180. doi: 10.1159/000509143. Epub 2020 Jun 11. PMID: 32526759; PMCID: PMC7360503. 4. Sudre CH, Keshet A, Graham MS, Joshi AD, Shilo S, Rossman H, Murray B, Molteni E, Klaser K, Canas LD, Antonelli M, Nguyen LH, Drew DA, Modat M, Pujol JC, Ganesh S, Wolf J, Meir T, Chan AT, Steves CJ, Spector TD, Brownstein JS, Segal E, Ourselin S, Astley CM. Anosmia, ageusia, and other COVID-19-like symptoms in association with a positive SARS-CoV-2 test, across six national digital surveillance platforms: an observational study. Lancet Digit Health. 2021 Sep;3(9):e577-e586. doi: 10.1016/S2589-7500(21)00115-1. Epub 2021 Jul 22. Erratum in: Lancet Digit Health. 2021 Sep;3(9):e542. PMID: 34305035; PMCID: PMC8297994. 5. Mak PQ, Chung KS, Wong JS, Shek CC, Kwan MY. Anosmia and Ageusia: Not an Uncommon Presentation of COVID-19 Infection in Children and Adolescents. Pediatr Infect Dis J. 2020 Aug;39(8):e199-e200. doi: 10.1097/INF.0000000000002718. PMID: 32516281. I am very very sorry to see that you did a huge effort in this analyses, but really the hypothesis behind the design of this study has a very doubtful significance. You should use these data to make a new one, doing f-up swabs as a minimum, or interview of parents to understand if further swabs have been done and the results to see how many of them are true negative. For example, a preprint from UK recently found that 1 out of 3 students had IgG positive (!!) confirming that the virus circulates much more than expected. And I am quite sure that among the negative, particularly those with known contacts and with anosmia/ageusia, you missed several cases. Thank you for your comment. We acknowledge the fact that the high rate of asymptomatic children might limit the predictiveness of symptoms, but we believe that this is an independent variable from the false positive issue. Moreover, IgG testing measures positivity in the span of several months, so that in a methodologic perspective, could not be related to symptoms or swab positivity in a defined moment. Finally, as mentioned above, the aim of this paper was not to demonstrate the circulation of the virus, but to identify clinical, anamnestic, and sociodemographic characteristics associated with a positive swab for SARS-CoV-2 in a population of children. Reviewer #2: In the manuscript authored by Benedetta Armocida et al, authors summarize clinical, anamnestic, and sociodemographic characteristics of children affected or not by Sars Cov-2 in a frame period between September 20th and December 23rd 2020. A major concern is that authors provided a study that is more descriptive then predictive, as stated from authors. This is a critical point. Thank you for your comment. We acknowledge the fact that the high rate of asymptomatic children makes limits the predictiveness of symptoms, but we believe that this is an independent variable from the false positive issue. We agree that in a blurred clinical setting, as SARS-CoV-2 infection in children, every study based on symptoms carries the risk of being more descriptive than predictive. This matter has been specified in text as a limitation, although concrete data on these issues are scant. No follow up is present. Thank you for your comment. At that time the general process after a positive swab envisaged the activation of quarantine and a swab at two weeks by the department of prevention. Thus, a follow up (control) swab was always performed, but these follow up swabs could have been performed in other departments or hospitals, not necessary in our Institute. Moreover, the aim of this study was to identify clinical, anamnestic, and sociodemographic characteristics associated with a positive swab for SARS-CoV-2in a population of children, hence we aimed at investigating a real life, pragmatic approach in order to try to add some clinical hints for clinicians and the symptoms presented at the time of the swab to observe if specific symptoms could be predictive of testing positivity, thus the follow up swab would have added, in our opinion, not significant information to the aim of the study. ROC curve is computed between 127 positive vs 1357 negative. Are these groups comparable? Thank for your comment. The two groups are comparable. As mentioned in the study population and in the inclusion criteria, all cases were children (2-14 years of age), coming from the general population of Trieste, all attending school or education services, and turning to the territorial services to undergo a RT-PCR nasopharyngeal swab to detect SARS-CoV-2, and only the ones with symptoms were included in the study. It is not clear to the reader if authors suggest NOT to perform Sars-Cov2 diagnostic test in children presenting rhinorrhoea, sore throat, or diarrhoea. Thank for your comment. To clarify, we are not suggesting clinicians not to perform SARS-CoV-2 diagnostic test in children presenting rhinorrhea, sore throat, or diarrhea, although we add the information that these symptoms carry a low risk of SARS-COV 2 infection. The information might be very relevant and might be helpful in orienting choices in specific settings, such as these with limited resources. This information has been included in the Discussion Attachments Attachment Submitted filename: PONE-D-21-24181 Response to reviewers.docx* https://doi.org/10.1371/journal.pone.0262923.r002
3 Nov 2021 Decision Letter - Robert Jeenchen Chen, Editor PONE-D-21-24181R1Clinical, anamnestic, and sociodemographic predictors of positive SARS-CoV-2 testing in children: a cross sectional study in a tertiary hospital in ItalyPLOS ONE Dear Dr. Ronfani, 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 revise. Please submit your revised manuscript by Dec 18 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Robert Jeenchen Chen, MD, MPH Academic Editor PLOS ONE [Note: HTML markup is below. Please do not edit.] 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: (No Response) Reviewer #2: All comments have been addressed ******** 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: No Reviewer #2: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: No Reviewer #2: Yes ****** 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: No Reviewer #2: Yes ****** 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 Reviewer #2: Yes ****** 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: I still think that a very single test cannot fully exclude covid in the negative control group, and therefore a study aiming to detect positive cases at the time of testing, without knowing days of illness and further follow-up is of limited value for a prestigious journal Reviewer #2: Authors provided most of the corrections requested from the reviewers and now the manuscript has been higly improved. ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0262923.r003
Revision 2
2 Dec 2021 Author Response 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: I still think that a very single test cannot fully exclude covid in the negative control group, and therefore a study aiming to detect positive cases at the time of testing, without knowing days of illness and further follow-up is of limited value for a prestigious journal *Thank you for your comment. We acknowledge and agree that a single test cannot completely exclude the positives in the negatives control group, therefore we explicitly included this point as limitations of the study. However, we considered this possibility extremely small, as our Institute was the only hub performing COVID-19 swab in the Trieste area (information added at the beginning of the methods section), hence in case of persistent or worsening symptoms, the access of these children for a second swab would have been performed within our Institute and this didn’t happen from our available data. Reviewer #2: Authors provided most of the corrections requested from the reviewers and now the manuscript has been higly improved. Thank you for your appreciation. Attachments Attachment Submitted filename: PONE-D-21-24181 Response to reviewers.docx* https://doi.org/10.1371/journal.pone.0262923.r004
21 Dec 2021 Decision Letter - Robert Jeenchen Chen, Editor PONE-D-21-24181R2Clinical, anamnestic, and sociodemographic predictors of positive SARS-CoV-2 testing in children: a cross sectional study in a tertiary hospital in ItalyPLOS ONE Dear Dr. Ronfani, 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 revise. Please submit your revised manuscript by Feb 04 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Robert Jeenchen Chen, MD, MPH Academic Editor PLOS ONE Journal Requirements: 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. [Note: HTML markup is below. Please do not edit.] 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 Reviewer #3: (No Response) ******** 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 Reviewer #3: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #3: Yes ****** 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: No Reviewer #3: Yes ****** 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 Reviewer #3: Yes ****** 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: thank you very much for this clarification, and thank you for having included it in the limitation section. this is an helpful addition and I think also you will benefit from this clarification when other colleagues will read this paper. I only ask one little addition: the authors NEVER compared in the discussion their findings with other italian ones, this should be done and particularly with an early national italian report , to also address if symptoms presentation have changed after the very early months (please refer to COVID-19 in 17 Italian Pediatric Emergency Departments, Parri, N., et al, Pediatrics, 2020, 146(6), e20201235) and even other ones would be appreciated Reviewer #3: This is an interesting study performed by Armocida et al, investigating the clinical, anamnestic and sociodemographic factors at the time of a positive SARS-CoV-2 test in children. The authors constructed a predictive model of SARS-CoV-2 positivity. My only concern is that whether any of the negative patients subsequently developed SARS-CoV-2. The authors state that none of the negative patients tested positive within their laboratory. Do they have data on whether children were retested and gave a negative test or there simply were no positive tests? My suspicion would be that if a child was negative then the likelihood of being retested would be relatively low. Without systematically testing patients while they continued to have symptoms then it is difficult to definitively answer this question. The authors must make it clear that these are the symptoms that the children had whilst they tested positive. In addition, do the authors have any data on how long the symptoms persisted prior to a positive test? ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #3: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. 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Revision 3
30 Dec 2021 Author Response PONE-D-21-24181R2 Clinical, anamnestic, and sociodemographic predictors of positive SARS-CoV-2 testing in children: a cross sectional study in a tertiary hospital in Italy PLOS ONE Reviewer #1: thank you very much for this clarification, and thank you for having included it in the limitation section. this is an helpful addition and I think also you will benefit from this clarification when other colleagues will read this paper. I only ask one little addition: the authors NEVER compared in the discussion their findings with other italian ones, this should be done and particularly with an early national italian report , to also address if symptoms presentation have changed after the very early months (please refer to COVID-19 in 17 Italian Pediatric Emergency Departments, Parri, N., et al, Pediatrics, 2020, 146(6), e20201235) and even other ones would be appreciated *Thank you very much for this additional request. We have included two Italian studies as references and compared the main findings also with an Italian study carried out in a similar outpatient setting and in the same school aged population (reference 8). References added: Parri N, Lenge M, Cantoni B, Arrighini A, Romanengo M, Urbino A, et al. COVID-19 in 17 Italian Pediatric Emergency Departments. Pediatrics. 2020 Dec;146(6):e20201235. doi: 10.1542/peds.2020-1235. Epub 2020 Sep 23. PMID: 32968031. Lazzerini M, Sforzi I, Trapani S, Biban P, Silvagni D, Villa G, et al. COVID-19 Italian Pediatric Study Network. Characteristics and risk factors for SARS-CoV-2 in children tested in the early phase of the pandemic: a cross-sectional study, Italy, 23 February to 24 May 2020. Euro Surveill. 2021 Apr;26(14):2001248. doi: 10.2807/1560-7917.ES.2021.26.14.2001248. PMID: 33834960; PMCID: PMC8034058. As mentioned in the first paragraph of our discussion though, to our knowledge, this is the first study to provide a predictive score for the paediatric population to identify children at risk to be positive to the SARS-CoV-2 test. Reviewer #3: This is an interesting study performed by Armocida et al, investigating the clinical, anamnestic and sociodemographic factors at the time of a positive SARS-CoV-2 test in children. The authors constructed a predictive model of SARS-CoV-2 positivity. My only concern is that whether any of the negative patients subsequently developed SARS-CoV-2. The authors state that none of the negative patients tested positive within their laboratory. Do they have data on whether children were retested and gave a negative test or there simply were no positive tests? My suspicion would be that if a child was negative then the likelihood of being retested would be relatively low. Without systematically testing patients while they continued to have symptoms then it is difficult to definitively answer this question. The authors must make it clear that these are the symptoms that the children had whilst they tested positive. Thank you very much for this comment. Unfortunately, we don’t have this additional information. As we mentioned in the limits, we acknowledge the possible limit in performing only one single test, which, without a further systematic follow-up, might have not detected a child positive to SARS-CoV-2, who might have been included in the negative control group. However, we considered this possibility extremely small, as our Institute was the only hub performing COVID-19 swab in the Trieste area, hence in case of persistent or worsening symptoms, the access of these children for a second swab would have been performed within our Institute and this didn’t happen from our available data. We added a sentence in the Methods section to clarify that we collected information on specific symptoms that led to the swab being administered. In addition, do the authors have any data on how long the symptoms persisted prior to a positive test? *Thank you very much for this comment. Unfortunately, we don’t have this additional information as data were collected at the time the RT-PCR testing was performed. This information was reported in Methods “data collection” section. Attachments Attachment Submitted filename: PONE-D-21-24181 Response to reviewers.docx* https://doi.org/10.1371/journal.pone.0262923.r006
10 Jan 2022 Decision Letter - Robert Jeenchen Chen, Editor Clinical, anamnestic, and sociodemographic predictors of positive SARS-CoV-2 testing in children: a cross sectional study in a tertiary hospital in Italy PONE-D-21-24181R3 Dear Dr. Ronfani, 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. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Robert Jeenchen Chen, MD, MPH 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 Reviewer #3: All comments have been addressed ******** 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 Reviewer #3: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #3: Yes ****** 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: No Reviewer #3: Yes ****** 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 Reviewer #3: Yes ****** 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: despite several limitations, the authors have replied to all concerns raised by authors. good luck. despite several limitations, the authors have replied to all concerns raised by authors. good luck. Reviewer #3: (No Response) ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #3: Yes:** Dr Simon T Abrams https://doi.org/10.1371/journal.pone.0262923.r007
Formally Accepted
14 Jan 2022 Acceptance Letter - Robert Jeenchen Chen, Editor PONE-D-21-24181R3 Clinical, anamnestic, and sociodemographic predictors of positive SARS-CoV-2 testing in children: a cross sectional study in a tertiary hospital in Italy Dear Dr. Ronfani: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Robert Jeenchen Chen Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0262923.r008

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