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Prevalence of SARS-CoV-2 positivity in infants with bronchiolitis: a multicentre international study
  1. Giorgio Cozzi1,
  2. Luisa Cortellazzo Wiel2,3,
  3. Alessandro Amaddeo1,
  4. Antonio Gatto4,
  5. Manuela Giangreco1,
  6. Adi Klein-Kremer5,
  7. Samantha Bosis6,
  8. Davide Silvagni7,
  9. Carla Debbia8,
  10. Laura Nanni9,
  11. Sara Chiappa10,
  12. Marta Minute11,
  13. Ilaria Corsini12,
  14. Giuliana Morabito13,
  15. Anna Jolanda Gortan14,
  16. Marco Colombo15,
  17. Federico Marchetti16,
  18. Davide Garelli17,
  19. Arianna Piffer18,
  20. Fabio Cardinale19,
  21. Nitai Levy20,
  22. Antonietta Curatola21,
  23. Bojana Gojsina22,23,
  24. Suvradeep Basu3,
  25. Egidio Barbi1,2,
  26. Aleksandar Sovtic22,23
  27. On behalf of the SARS-CoV-2 bronchiolitis study group
    1. 1 IRCCS Materno Infantile Burlo Garofolo, Trieste, Italy
    2. 2 University of Trieste, Trieste, Italy
    3. 3 Bradford Royal Infirmary, Bradford, UK
    4. 4 Policlinico Universitario Agostino Gemelli, Roma, Italy
    5. 5 Hillel Yaffe Medical Center, Hadera, Israel
    6. 6 Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
    7. 7 Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
    8. 8 Istituto Giannina Gaslini Istituto Pediatrico di Ricovero e Cura a Carattere Scientifico, Genova, Italy
    9. 9 Azienda Ospedaliero Universitaria Meyer, Firenze, Italy
    10. 10 Ospedale dei Bambini di Brescia, Brescia, Italy
    11. 11 Ospedale Regionale Ca Foncello Treviso, Treviso, Italy
    12. 12 University Hospital of Bologna Sant'Orsola-Malpighi Polyclinic, Bologna, Italy
    13. 13 Ospedale Santa Maria degli Angeli di Pordenone, Pordenone, Italy
    14. 14 Azienda sanitaria universitaria Friuli Centrale, Udine, Italy
    15. 15 ASST Sette Laghi, Varese, Italy
    16. 16 Ospedale Santa Maria delle Croci, Ravenna, Italy
    17. 17 Regina Margherita Children's Hospital, Turin, Italy
    18. 18 Regional Hospital of Bellinzona and Valli, Bellinzona, Switzerland
    19. 19 Ospedale Pediatrico Giovanni XXIII, Bari, Italy
    20. 20 Ruth Rappaport Children's Hospital, Haifa, Israel
    21. 21 Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Roma, Italy
    22. 22 Institute for Health Protection of Mother and Child of Serbia 'Dr Vukan Cupic', Beograd, Serbia
    23. 23 University of Belgrade Faculty of Medicine, Beograd, Serbia
    1. Correspondence to Dr Luisa Cortellazzo Wiel, University of Trieste, Trieste, Italy; luisacortellazzowiel{at}


    Background Bronchiolitis is the leading acute respiratory tract infection in infants during the winter season. Since the beginning of the SARS-CoV-2 pandemic, a reduction in the number of bronchiolitis diagnoses has been registered.

    Objective The present study aimed to describe the incidence and clinical features of bronchiolitis during the 2020–2021 winter season in a large cohort of children in Europe and Israel, and to clarify the role of SARS-CoV-2.

    Setting, patients, interventions We conducted a multicentre observational cross-sectional study in 23 paediatric emergency departments in Europe and Israel. Clinical and demographic data about all the cases of infants diagnosed with bronchiolitis from 1 October 2020 to 30 April 2021 were collected. For each enrolled patient, diagnostic tests, treatments and outcomes were reported.

    Main outcome measures The main outcome was the prevalence of SARS-CoV-2-positive bronchiolitis.

    Results Three hundred and fourteen infants received a diagnosis of bronchiolitis during the study period. Among 535 infants who tested positive for SARS-CoV-2, 16 (3%) had bronchiolitis. Median age, male sex predominance, weight, history of prematurity and presence of comorbidities did not differ between the SARS-CoV-2-positive and SARS-CoV-2-negative groups. Rhinovirus was the most common involved pathogen, while respiratory syncytial virus (RSV) was detected in one case. SARS-CoV-2 bronchiolitis had a mild clinical course, with one patient receiving oxygen supplementation and none requiring paediatric or neonatal intensive care unit admission.

    Conclusions During the SARS-CoV-2 pandemic, a marked decrease in the number of bronchiolitis diagnoses and the disappearance of the RSV winter epidemic were observed. SARS-CoV-2-related bronchiolitis was rare and mostly displayed a mild clinical course.

    • COVID-19
    • epidemiology
    • intensive care units
    • paediatric emergency medicine
    • virology

    Data availability statement

    Data are available on reasonable request.

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    • Collaborators Itai Shavit, Pediatric Emergency Department, Ruth Rappaport Children’s Hospital, Rambam Health Care Campus, Haifa, Israel. Federica Vanoni, Clinic of Pediatrics, Pediatric Institute of Southern Switzerland, EOC, Bellinzona, Switzerland. Alessandra Iacono, Department of Pediatrics, Santa Maria delle Croci Hospital, Ravenna, Italy. Stefano Masi, Pronto Soccorso Pediatrico, Azienda Ospedaliero Universitaria Meyer, Firenze. Emanuela Piccotti, Pronto Soccorso Pediatrico, IRCCS pediatrico Gaslini, Genova. Anna Maria Plebani, Pronto Soccorso Pediatrico, Ospedale Filippo del Ponte, ASST Sette Laghi, Varese, Italy. Valentina Tranchino, Department of Pediatrics and Emergency, Pediatric Hospital Giovanni XXIII, Bari, University of Bari, Italy. Gregorio Paolo Milani, Pediatric Unit, Fondazione IRCCS Ca’ Granda-Ospedale Maggiore Policlinico, Milano, Lombardia, Italy; Department of Clinical Science and Community Health, Università degli Studi di Milano, Milan, Lombardia, Italy. Sara Pedicini, Clinica Pediatrica, Azienda Sanitaria Universitaria Integrata Friuli Centrale (ASUFC). Vered Nir, Hillel Yaffe Medical Center, Haifa, Israel. Jelena Visekruna, Mother and Child Health Institute of Serbia and School of Medicine University of Belgrade.

    • Contributors GC conceived and supervised the work. LCW, AG, AK-K, SB, DS, CD, LN, SC, MM, IC, GM, AJG, MC, FM, DG, AP, FC, NL, AC, BG, SB and AS collected the data. MG performed the statistical analysis, GC and AA wrote the first draft of the manuscript. EB edited the final version of the manuscript.

    • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

    • Competing interests None declared.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.