Human respiratory syncytial virus (HRSV) is a major cause of severe respiratory tract illnesses in infants and young children worldwide. Despite its importance as a respiratory pathogen, there is currently no licensed vaccine for HRSV. Following failure of the initial trial of formalin-inactivated virus particle vaccine, continuous efforts have been made for the development of safe and efficacious vaccines against HRSV. However, several obstacles persist that delay the development of HRSV vaccine, such as the immature immune system of newborn infants and the possible Th2-biased immune responses leading to subsequent vaccine-enhanced diseases. Many HRSV vaccine strategies are currently being developed and evaluated, including live-attenuated viruses, subunit-based, and vector-based candidates. In this review, the current HRSV vaccines are overviewed and the safety issues regarding asthma and vaccine-induced pathology are discussed.
Asthma ; Child ; Humans ; Immune System ; Infant ; Infant, Newborn ; Respiratory Syncytial Virus, Human ; Respiratory Syncytial Viruses ; Respiratory System ; Vaccines ; Virion

Human Respiratory Syncytial virus (hRSV) is a leading cause of severe lower respiratory tract diseases in the pediatric population.hRSV frequently causes severe morbidity and mortality in high risk groups including infants with congenital heart disease and the immunosuppressed patients. Although hRSV is recognized as a major public health threat and economic burden worldwide, there is no licensed vaccine and effective therapeutic agent. Viral nonstructural (NS) proteins have been known to play multiple functions for efficient viral replication and pathogenesis. Especially, diverse functions of influenza A virus NS1 have been extensively studies. Recent studies demonstrated that NS1 and NS2 of RSV also exert diverse functions to modulate cellular environment and antiviral immune responses. Since NS proteins of RSV are required for efficient replication and pathogenesis, NS mutant viruses have been tested as live-attenuated vaccines. This review will outline the recent progress in understanding the various functions of RSV NS1 and NS2.
Heart Defects, Congenital ; Humans ; Infant ; Influenza A virus ; Interferons ; Mortality ; Public Health ; Respiratory Syncytial Virus, Human ; Respiratory Syncytial Viruses* ; Respiratory Tract Diseases ; Vaccines

Human respiratory syncytial virus (HRSV) is known as the leading cause of respiratory tract illness in infancy and elderly children worldwide. We investigate the prevalence pattern and genetic characteristics in the second variable region G protein gene of HRSV during 5 consecutive seasons from 2010 to 2015. A total of 4,793 specimens (throat swabs) were collected from patients with acute respiratory tract. HRSV were evaluated and classified as HRSV A (n=111) or HRSV B (n=64) by real-time RT-PCR or RT-PCR. In general HRSV were detected in winter season. Coughing, fever, rhinorrhea and sputum were confirmed main symptoms in patients with HRSV. There were no significant differences in clinical characteristics or severity according to the HRSV subgroup infections. Out of 175 HRSV positive samples, 94 samples were successfully sequenced using G gene. Phylogenetic analysis revealed that 62 HRSV-A strains clustered into genotypes ON1 (n=54, 87.1%), NA1 (n=7), NA2 (n=1) and 32 HRSV-B strains clustered into three genotypes: BA4 (n=28, 87.5%), BA5 (n=2), BA6 (n=2). These results provide a better understanding of HRSV prevalence pattern and genetic characteristics.
Aged ; Busan* ; Child ; Communicable Diseases* ; Cough ; Fever ; Genotype ; GTP-Binding Proteins ; Humans ; Prevalence ; Respiratory Syncytial Virus, Human ; Respiratory Syncytial Viruses* ; Respiratory System ; Seasons ; Sputum

Laboratory diagnosis of respiratory viral infection has traditionally been based upon virus isolation and/or viral antigen identification. Recently, more sensitive and specific nucleic acid detection methods by reverse transcription- polymerase chain reaction (RT-PCR) have been developed, however, conventional RT-PCR can identify only a single suspected virus. To identify the causative agents which belong to Paramyxoviridae of respiratory virus infections, we have developed a single-tube multiplex RT-PCR using four primer sets which can amplify respiratory syncytial virus and parainfluenza virus type 1, 2 and 3 simultaneously. Assay sensitivity of single-tube multiplex RT-PCR allowed a detection in the range of 3~500 TCID50 and there were no cross amplification among other respiratory viral agents based on the test using reference virus stocks. The single-tube multiplex RT-PCR was able to directly detect viruses in respiratory specimens, with virus being detected 11 of 80 samples as compared to 9 of 80 samples detected by indirect immunofluorescence or antigen detection following shell vial culture. This result suggests that the single-tube multiplex RT-PCR can be established as a more sensitive and rapid diagnostic application than shell vial assay for the detection of respiratory infection of Paramyxoviridae.
Clinical Laboratory Techniques ; Fluorescent Antibody Technique, Indirect ; Humans* ; Parainfluenza Virus 1, Human* ; Paramyxoviridae ; Paramyxoviridae Infections* ; Polymerase Chain Reaction* ; Respiratory Syncytial Virus, Human* ; Respiratory Syncytial Viruses ; Reverse Transcription*

OBJECTIVETo investigate the infection status and epidemiological characteristics of influenza virus and respiratory syncytial virus (RSV) in influenza-like illness (ILI) of children ( ≤ 14 years) in Wuhan area from 2008 to 2012.

METHODSA total of 2854 cases of ILI patients ( ≤ 14 years) in a hospital of Wuhan were recruited in the study from July 2008 to June 2012. The sample of pharyngeal swab was collected from each patient, to extract the virus nucleic acids. Real-time fluorescent quantitation reverse transcription PCR (RT-PCR) method was applied to detect the subtypes of influenza virus and RSV, and then analyzed the time and age characteristics.

RESULTSOut of the 2854 cases, 758 (26.6%) were positive for influenza virus,including 547 (19.2%) influenza A virus positive samples and 211 (7.4%) influenza B virus positive samples. Usually, there were two peaks present in the annual curve of influenza virus, namely summer peak and winter/spring peak. The positive rate of influenza virus in 6-14 years old children (48.0%, 275/573) was significantly higher than that in 3-5 years old children (26.6%, 213/801) and that under 3 years old children (18.3%, 270/1480). The difference showed statistical significance (χ(2) = 187.432, P < 0.01). A total of 219 (7.7%) cases were positive for RSV,including 108 RSV-A positive samples and 112 RSV-B positive samples (1 co-infection). The epidemic of RSV showed an obvious seasonal pattern with peaks in autumn,winter and spring,which accounted for 96.8% (212/219) of all the cases; however, the annual incidence of RSV fluctuated greatly. The predominant subtype shifted every 2 years. RSV-B predominated during September 2008 and May 2009, December 2009 and March 2010, accounting for 76.6% (36/47) and 96.9% (62/64) respectively. RSV-A predominated during November 2010 and March 2011, September 2011 and April 2012, accounting for 92.5% (37/40) and 100.0% (48/48) respectively. With the increase of the age, the positive rate of RSV-A and RSV-B decreased gradually (RSV-A: χ(2) = 36.223, P < 0.01; RSV-B: χ(2) = 36.281, P < 0.01). The positive rates of RSV-A in children < 1,1,2,3,4,5-9 and 10-14 years old were 7.0% (26/373), 5.9% (39/662), 4.0% (18/445), 3.2% (13/406), 1.3% (3/236), 1.4% (7/517) and 0.9% (2/215) respectively; while, the positive rates of RSV-B in each age group were 6.4% (24/373), 6.0% (40/662), 4.5% (20/445), 4.4% (18/406), 1.3% (3/236), 1.0% (5/517) and 0.9% (2/215) respectively. The children aged 0-3 years old were more susceptible for RSV infection,accounting for 90.0% (197/219) of the total positive samples. During the outbreak of influenza A H1N1 in November 2009, the positive rate of RSW was 3.0% (3/100), lower than that in the same month of 2008, 2010 and 2011,which were separately 18.2% (6/33), 10.8% (10/93) and 10.0% (4/40). The difference showed statistical significance (χ(2) = 8.450, P < 0.05). During the outbreak of influenza A (H1N1) in January 2011,the positive rate of RSV was 5.7% (3/53), lower than those in the same month of 2009, 2010 and 2012, which was separately 21.7% (5/23), 28.6% (22/77) and 16.0% (8/50). The difference showed statistical significance (χ(2) = 11.233,P < 0.05). During the period of less influenza happened in September 2011, the RSV positive rate was 25.0% (10/40), higher than those in the same month of 2008, 2009 and 2010, which was separately 11.4% (4/35), 1.7% (2/118) and 0.0% (0/109). The difference showed statistical significance (χ(2) = 32.521, P < 0.01).

CONCLUSIONBoth influenza virus and RSV were important etiological agents of ILI of children in Wuhan. The characteristics of seasonal and age distributions of the two viruses were notably different; meanwhile, a certain inhibitional effect of influenza virus on RSV could be observed.

Adolescent ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Humans ; Influenza, Human ; epidemiology ; Male ; Orthomyxoviridae ; classification ; isolation & purification ; Respiratory Syncytial Virus Infections ; epidemiology ; Respiratory Syncytial Viruses ; classification ; isolation & purification

BACKGROUND: Infection with respiratory virus has been shown to exacerbate asthma. However, the role of a respiratory virus in the pathogenesis of chronic asthma and/or wheezing in young children has not been clearly defined. And it also has been debated whether virus-induced wheezing in young children is an entity different from allergic asthma, or just a different expression of the same disease. In this study, we attempted to evaluate the importance of eosinophilic inflammation, comparing IL-5 and IFN-gamma levels in nasopharyngeal secretions in wheezing children with or without viral infection and the controls. METHODS: We compared IL-5 and IFN-gamma levels in nasopharyngeal secretions from 38 non-asthmatic wheezing children with viral infections (RSV in 21 children, influenza A virus in 17 children), 12 asthmatic children without viral infections and 16 children as the controls. RESULTS: The present study reported that RSV infection in children induced more releasing of IL-5 in nasopharyngeal secretions than the influenza A virus infected ones and the controls. On the other hand, the releasing of IFN-gamma levels in nasopharyngeal secretions from children with influenza A virus infection was significantly higher than those of the children with RSV infection or asthmatic children. CONCLUSION: RSV infection in children may play a role in the immune response toward a Th2 phenotype as increasing IL-5 secretion in nasopharyngeal secretion. Increased IFN-gamma production in response to the influenza A virus infection may be related to the effective Th1 responses.
Asthma ; Child* ; Eosinophils ; Hand ; Humans ; Inflammation ; Influenza A virus* ; Influenza, Human* ; Interferon-gamma ; Interleukin-5* ; Phenotype ; Respiratory Sounds* ; Respiratory Syncytial Viruses*

PURPOSE: Acute lower respiratory tract infections (ALRI) in children are mostly caused by viruses. This study aimed to define the causative viruses, and clinical manifestations during 4 years (2002-2006) and to determine seasonal occurrence of viral ALRI in Korean children by using our cumulative 10 year data (1996-2006). METHODS: A total of 3,854 hospitalized patients due to viral ALRI at Samsung Medical Center, from October 2002 to July 2006, were analyzed. Nasopharyngeal aspirate was obtained for virus cultures. Respiratory viruses were identified using indirect immunofluorescent staining. RESULTS: Viral agents were isolated in 9.8% (378 cases). The common identified pathogens were parainfluenza virus type 3 (32.3%), respiratory syncytial virus (RSV) (29.6%) and adenovirus (14.0%). The clinical patterns of viral ALRI were pneumonia (73.0%), bronchiolitis (20.9%), croup (3.7%) and tracheobronchitis (2.4%). The occurrence of viral ALRI was highest under 2 years of age. Pneumonia developed mostly by parainfluenza virus type 3 and RSV. The most frequent cause of bronchiolitis was RSV. Croup was frequently caused by parainfluenza virus. During the past 10 years, infections with parainfluenza virus type 3 and RSV epidemically occurred, whereas adenovirus was isolated throughout the study period. CONCLUSION: We could look through the etiological aspect of ALRI among pediatric inpatients during 10 years in Seoul by adding this 4 year data to the former 6 years data in our hospital. Our results may contribute to prevention and control of viral respiratory tract infections.
Adenoviridae ; Bronchiolitis ; Child ; Child, Hospitalized ; Croup ; Epidemiologic Studies ; Humans ; Inpatients ; Korea ; Parainfluenza Virus 3, Human ; Paramyxoviridae Infections ; Pneumonia ; Respiratory Syncytial Viruses ; Respiratory System ; Respiratory Tract Infections ; Seasons ; Viruses

BACKGROUND: Tego-51(R), one of the amphoteric surfactants, has been considered as an effective disinfectant having both bactericidal and fungicidal effect. The author evaluated inactivation effect of Tego-51(R) on viruses causing disease in humans. METHODS: Influenza virus B, respiratory syncytial virus (RSV), herpes simplex virus 1 (HSV-1), adenovirus and echovirus 30 were exposed to diluted Tego-51(R) solution (1% and 0.1%) for 5, 10 and 30 minutes respectively and were inoculated onto the following cells: Influenza virus B, MDCK; RSV, HEp-2; HSV-1, HEp-2; adenovirus, Vero; and echovirus 30, RD. After incubation for 5 to 6 days, viral infection was identified with indirect immunofluorescent methods. RESULTS: Influenza virus B, RSV and HSV-1 which are enveloped viruses were inactivated after exposure of the viruses to Tego-51(R) for 5 minutes. Non-enveloped adenovirus and echovirus 30 were not inactivated after exposure for 30 minutes. CONCLUSIONS: Tego-51(R) appears to be effective in inactivation of enveloped viruses at concentrations used for disinfection of pathogenic bacteria and fungi.
Adenoviridae ; Bacteria ; Disinfection ; Enterovirus B, Human ; Fungi ; Herpesvirus 1, Human ; Humans ; Orthomyxoviridae ; Respiratory Syncytial Viruses ; Surface-Active Agents ; Virus Inactivation*

PURPOSE: Croup, a common childhood respiratory illness with various severities, has many unanswered questions. Laryngotracheobronchopneumonitis (LTBP) is a disease entity considered to be an extension of croup to the lower respiratory tract. The object of this study was to compare epidemiology, clinical characteristics, and viral etiologic spectrum between croup and LTBP. METHODS: Patients hospitalized with croup at Gachon University Gil Hospital from January 2010 to April 2016 were recruited. LTBP was defined as pneumonia confirmed on radiographs of patients with croup. Clinical findings and demographic data were reviewed of patients whose nasopharyngeal swabs were done for viral analysis. RESULTS: A total of 371 patients with only croup and 63 patients with LTBP were included. Croup was found to be significantly associated with parainfluenza virus type 1 (P=0.006). LTBP was related to parainfluenza virus type 3, respiratory syncytial virus, and human bocavirus (P=0.001, P=0.030, and P=0.019, respectively). The duration of fever was longer in patients with LTBP than in those with croup (3.87±1.85 days vs. 2.86±1.80 days, P<0.001). CONCLUSION: Specific etiologic viruses might be associated with the progression from croup to LTBP. Pronged fever is also associated with progression from croup to LTBP.
Child* ; Croup* ; Epidemiology ; Fever ; Human bocavirus ; Humans ; Parainfluenza Virus 1, Human ; Parainfluenza Virus 3, Human ; Pneumonia ; Respiratory Syncytial Viruses ; Respiratory System

BACKGROUND: Acute lower respiratory tract infections are common causes of hospitalization in children and viruses are major causative agents. The causative viruses are known to be variable by age, region, or year. We investigated the recent 5-year epidemics of respiratory viruses for pediatric patients in two university hospitals in Korea. MATERIALS AND METHODS: From July 1996 through June 2001, viral agents were detected for the 2,317 pediatric patients who were hospitalized with acute respiratory tract infection in Hanyang University Hospital and Hanyang University Guri Hospital. We obtained nasopharyngeal aspirates on the day of admission and detected the viruses by indirect immunofluorescent staining method (Respiratory panel I viral Screening & Identification Kit, Light Diagnostics, Chemicon, Temecula, CA, USA). RESULTS: The causative viral agents were detected in 737(31.76%) patients. They were respiratory syncytial virus of 53.6%, influenza A virus 38.6%, adenovirus 5.5%, influenza B virus 1.9%, and parainfluenzavirus 0.4%. The epidemics of RSV were found during winter, but the epidemics of influenza A were found more frequently in spring, which had tendency of following the epidemic of RSV. Adenovirus was detected sporadically throughout year. RSV was found more frequently in patient with bronchiolitis and pneumonia and also found more frequently in patient less than 6 month of age. Influenza A and adenovirus were in patients of pneumonia and in more frequently in patient one to two year of age. CONCLUSION: Viruses were the leading causative agents of acute lower respiratory tract infections in pediatric patients. RSV was the most important causative agent. Influenza A virus was the second frequent viral agent and detection rate was higher than other reports. The detection rate of parainfluenza virus was lower than other reports from Korea or from abroad.
Adenoviridae ; Bronchiolitis ; Child ; Hospitalization ; Hospitals, University ; Humans ; Influenza A virus ; Influenza B virus ; Influenza, Human ; Korea ; Mass Screening ; Orthomyxoviridae ; Paramyxoviridae Infections ; Pneumonia ; Respiratory Syncytial Viruses ; Respiratory Tract Infections