• Pediatric Infection and Vaccine
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• v.20 no.3
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• pp.178-185
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• 2013

Objective: Cytopenia is a common hematologic complication of viral infections. However, information regarding hematologic effects of common respiratory virus infections is scarce. This study aimed to evaluate hematologic complications and the clinical course of patients infected with common respiratory viruses. Methods: We retrospectively analyzed 496 patients with respiratory tract infections admitted to the Department of Pediatrics, Wonkwang University Hospital from November 2011 to March 2012 using multiplex real-time polymerase chain reaction to detect the presence of respiratory viruses and hematologic abnormalities. Results: Respiratory viruses were identified in 379 patients. Respiratory syncytial virus (RSV) was most frequently detected (55.7%), followed by influenza A (Flu-A, 23.0%). Further, cytopenia was observed in 35.5% of RSV-infected patients, 25.0% of Flu-A-infected patients, and 34% of patients infected by other viruses. Each virus caused a decrease in 3 blood cell component values, which corresponded with cytopenia frequency. Of the 379 infected patients, 83 had anemia ($9.71{\pm}1.09g/dL$); 46 had neutropenia ($803.70{\pm}263.09cells/mm^3$); and 23 had transient thrombocytopenia ($142,434.78{\pm}86,835.18cells/mm^3$). However, no patient required treatment. A comparison of clinical characteristics between RSV- and Flu-A-positive patients with anemia revealed that RSV-infected patients had significantly longer duration of hospitalization. RSV was detected more commonly in young neutropenic patients, who had a shorter duration of fever. Conclusions: Our findings suggest that infections, particularly RSV and Flu-A, result in varying degrees of cytopenia, which usually improves without treatment and does not affect the clinical course of the infection.

• Tuberculosis and Respiratory Diseases
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• v.80 no.4
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• pp.358-367
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• 2017

Background: Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. Methods: Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. Results: A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ${\geq}16years$, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. Conclusion: The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia.

• Clinical and Experimental Pediatrics
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• v.53 no.3
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• pp.373-379
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• 2010

Purpose : This study was performed to investigate the epidemiologic and clinical features of 13 respiratory viruses in children with acute lower respiratory tract infections (ALRIs). Methods : Nasopharyngeal aspirates were prospectively obtained from 325 children aged 15 years or less from May 2008 to April 2009 and were tested for the presence of 13 respiratory viruses by multiplex real-time-polymerase chain reaction (RT-PCR). Results : Viruses were identified in 270 children (83.1%). Co-infections with ${\geq}2$ viruses were observed in 71 patients (26.3 %). Respiratory syncytial virus (RSV) was the most common virus detected (33.2%), followed by human rhinovirus (hRV) (19.1%), influenza virus (Flu A) (16.9%), human metapneumovirus (hMPV) (15.4%), parainfluenza viruses (PIVs) (8.3%), human bocavirus (hBoV) (8.0%), adenovirus (ADV) (5.8%), and human coronavirus (hCoV) (2.2%). Clinical diagnoses of viral ALRIs were bronchiolitis (37.5%), pneumonia (34.5%), asthma exacerbation (20.9%), and croup (7.1%). Clinical diagnoses of viral bronchiolitis and pneumonia were frequently demonstrated in patients who tested positive for RSV, hRV, hMPV, or Flu A. Flu A and hRV were most commonly identified in children older than 3 years and were the 2 leading causes of asthma exacerbation. hRV C was detected in 14 (4.3%) children, who were significantly older than those infected with hRV A ($mean{\pm}SD$, $4.1{\pm}3.5$ years vs. $1.7{\pm}2.3$ years; P =0.009). hBoV was usually detected in young children ($2.3{\pm}3.4$ years) with bronchiolitis and pneumonia. Conclusion : This study described the features of ALRI associated with 13 respiratory viruses in Korean children. Additional investigations are required to define the roles of newly identified viruses in children with ALRIs.

• Pediatric Infection and Vaccine
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• v.24 no.3
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• pp.134-140
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• 2017

Purpose: Severe combined immunodeficiency (SCID) is the most serious form of primary immunodeficiency. Infants with SCID are susceptible to life-threatening infections. To establish newborn screening for SCID in Korea, we performed a screening test for T-cell receptor excision circle (TREC) and ${\kappa}$-deleting recombination excision circle (KREC) in neonates and investigated the awareness of SCID among their parents. Methods: Collections of dried blood spots from neonates and parent surveys were performed at the Samsung Medical Center and Cheil General Hospital & Women's Healthcare Center in Korea. The amplification crossing point (Cp) value <37.0 was defined as TREC/KRECpositive based on cutoff values from measuring multiplex real-time polymerase chain reaction. A Cp value >39.0 was defined as negative. Results: For TREC/KREC screening, 141 neonates were enrolled; 63 (44.7%) were male. One hundred forty neonates (99.3%) had positive TREC/KREC results at the time of the initial test; 82.3% and 75.9% were positive and 17.0% and 23.4% were weakly positive for TREC and KREC, respectively. In one neonate (0.7%), the initial TREC/KREC test result was negative. However, repeated tests obtained and confirmed a positive result. For an awareness survey, 168 parents were engaged. Only 2% of parents (3/168) knew that the newborn screening test for SCID had been introduced and performed in other countries. Eighty-four percent of parents (141/168) replied that nationwide newborn SCID screening should be performed in Korean newborns. Conclusions: In this study, newborn SCID screening was performed along with assessment of public awareness of the SCID test in Korea. The study results showed that newborn SCID screening can be readily applied for clinical use at a relatively low cost in Korea.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.154-162
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• 2011

Purpose : The aim of this study was to identify the clinical characteristics of lower respiratory tract infection due to respiratory syncytial virus (RSV) in young children and to provide information for an effective guideline for palivizumab administration in Korea. Methods : We reviewed medical charts of 167 patients under 3 years of age who were hospitalized in Dongguk University Ilsan Hospital for lower respiratory tract infection between January 2007 and February 2011. Diagnosis of the virus was made based on the multiplex real time polymerase chain reaction. Results : There were 113 patients who were infected by respiratory syncytial virus. 90 patients were term infants and 23 patients were preterm infants. No difference was shown between term and preterm infants except the days of admission which was 9.0${\pm}$6.0 days and 12.6${\pm}$21.0 days respectively. In the preterm group their mean age at the time of admission was 5.21${\pm}$4.9 months and the mean gestational age was 33.1${\pm}$4.3 weeks, and the mean birth weight was 2,152${\pm}$950 g. Only 4 patients were born under 28 weeks gestational age and were candidates for palivizumab administration. Conclusion : Most of the patients with severe RSV lower respiratory tract infection were term or near term infants who were not candidates for palivizumab prophylaxis. A nationwide study is needed to make a new risk stratified guideline for RSV prophylaxis for our country.