Pediatr Infect Vaccine.  2018 Apr;25(1):8-16. 10.14776/piv.2018.25.1.8.

Epidemiology and Clinical Severity of the Hospitalized Children with Viral Croup

  • 1Department of Pediatrics, Yonsei University Wonju College of Medicine, Wonju, the Republic of Korea.


In this study, the clinical and epidemiological characteristics of patients admitted for viral croup were analyzed to evaluate disease severity based on the organism that caused the infection.
We retrospectively reviewed the medical records of 302 patients who were admitted to the Department of Pediatrics at the Wonju Severance Hospital between May 2013 and December 2016 for viral croup. Patients who showed positive results on multiplex polymerase chain reaction were subsequently diagnosed with respiratory virus infection. The Westley scoring system was used to evaluate the severity of viral croup.
Of the 302 patients, 149 were admitted due to severe viral croup, including 88 boys and 61 girls, with a boy-to-girl ratio of 1.44:1. About 110 cases of parainfluenza virus infection have been reported, which accounted for almost half of the total cases. The other identified viruses included influenza virus, human rhinovirus, and respiratory syncytial virus. Analysis of the association between severe viral croup and causative pathogen revealed that only parainfluenza type 2 virus showed a significantly high risk. Parainfluenza type 2 virus did not show an age-based difference in frequency but showed relatively a higher frequency of infections during the summer and fall.
In this study, parainfluenza virus type 2 was the only virus associated with severe viral croup. To facilitate proper preventive management, treatment, and prognosis evaluation of viral croup, prospective and multicenter studies should assess the additional variables and the severity of the virus. Additionally, further studies should be conducted to assess age-dependent influences, as well as the regional and seasonal incidence of viral infection.


Croup; Epidemiology; Severity of illness index; Multiplex polymerase chain reaction; Child, hospitalized

MeSH Terms

Child, Hospitalized*
Medical Records
Multiplex Polymerase Chain Reaction
Parainfluenza Virus 2, Human
Paramyxoviridae Infections
Prospective Studies
Respiratory Syncytial Viruses
Retrospective Studies
Severity of Illness Index


  • Fig. 1. Distribution of detected viruses in children with viral croup according to age: (A) 1 year or less, (B) 1 year, (C) 2 year, and (D) 3 year or more, Abbreviations: PIV, parainfluenza virus; RSV, respiratory syncytial virus; Flu, Influenza virus; hRV, human rhinovirus; hMPV, human metapneumovirus; NL63, human coronavirus NL63; OC43, human coronavirus OC43; ADV, adenovirus; hBoV, human bocavirus.

  • Fig. 2. Distribution of detected viruses in children with viral croup according to seasons: (A) spring, (B) summer, (C) autumn, and (D) winter, Abbreviations: PIV, parainfluenza virus; RSV, respiratory syncytial virus; Flu, Influenza virus; hRV, human rhinovirus; hMPV, human metapneumovirus; NL63, human coronavirus NL63; OC43, human coronavirus OC43; ADV, adenovirus; hBoV, human bocavirus.

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Seasonality and etiology of croup in pediatric patients hospitalized with lower respiratory tract infections: A long-term study between 2009 and 2017
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Seasonal patterns and etiologies of croup in children during the period 2010–2015: A multicenter retrospective study
Yong Ju Lee, Hyo-Bin Kim, Bong-Seong Kim, Chang-Keun Kim, Cheol Hong Kim, Hyung Young Kim, Sangyoung Kim, Yunsun Kim, Chorong Park, Ju-Hee Seo, In Suk Sol, Myongsoon Sung, Min Seob Song, Dae Jin Song, Young Min Ahn, Ju Suk Lee, Yoon Young Jang, Eun Hee Chung, Hai Lee Chung, Sung-Min Choi, Yun Jung Choi, Man Yong Han, Hyeon-Jong Yang, Jung Yeon Shim, Jin-Tack Kim, Hea Lin Oh, Jinho Yu, Kyung Suk Lee, Eun Lee, Gwang Cheon Jang
Allergy Asthma Respir Dis. 2019;7(2):78-85.    doi: 10.4168/aard.2019.7.2.78.



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