Epidemiology of acute viral respiratory tract infections in Korean children

Age-Specific Characteristics of Adult and Pediatric Respiratory Viral Infections: A Retrospective Single-Center Study

This study aimed to identify age-specific characteristics of respiratory viral infections. Hospitalized patients with confirmed viral respiratory infections were included in the sample. The patients were divided into the pediatric group (<19 years old) and the adult group (≥19 years old). The groups were then subdivided based on age: 0−6, 7−12, 13−18, 19−49, 50−64, and ≥65 years old. These groups were compared to evaluate the differences in the pattern of respiratory viral infections. Among a total of 4058 pediatric patients (mean age 3.0 ± 2.9 years, n = 1793 females), 2829 (48.9%) had mono-infections, while 1229 (51.1%) had co-infections. Co-infections were the most common in the 0−6-year-old group (31.6%). Among 1550 adult patients (mean age 70.2 ± 15.3 years, n = 710 females), 1307 (85.6%) had mono-infections and 243 (14.4%) had co-infections. Co-infections were most common in the ≥65-year-old group (16.8%). Viral infection and co-infection rates decreased with age in pediatric patients but increased with increasing age in adults. In pediatric patients, the rates of viral infections and co-infections were high; the rate of co-infections was higher in younger patients. In adult patients, the rates of viral infections and co-infections were lower than those in pediatric patients; the rate of co-infections was higher in older patients.

Analysis of the Association Among Air Pollutants, Allergenic Pollen, and Respiratory Virus Infection of Children in Guri, Korea During Recent 5 Years

PURPOSE

Concerns about the spread of infectious diseases have increased due to the coronavirus disease pandemic. Knowing the factors that exacerbate or increase the contagiousness of a virus could be a key to pandemic prevention. Therefore, we investigated whether the pandemic potential of infectious diseases correlates with the concentration of atmospheric substances. We also investigated whether environmental deterioration causes an increase in viral infections.

METHODS

Pediatric patients (0-18 years old; n = 6,223) were recruited from those hospitalized for aggravated respiratory symptoms at Hanyang University Guri Hospital between January 1, 2015 and December 31, 2019. The number of viral infections was defined as the total number of virus-infected patients hospitalized for respiratory symptoms. We analyzed the association between the number of viral infections/week and the average concentrations of atmospheric substances including particulate matter (PM)10, PM2.5, O₃, NO₂, CO, SO₂, and allergenic pollen) for that week. The cross-correlation coefficient between the weekly measures of pollens and viral infections was checked to determine which time point had the most influence. The association of atmospheric substances in that time, with the number of viral infections/week was investigated using multiple linear regression analysis to identify factors with the greatest influence.

RESULTS

In spring the tree pollen average concentration one week earlier (t-1) had the greatest correlation with the average virus infection of a given week (t) (ρXY (h) =0.5210). The number of viral infections showed a statistically significant correlation with especially tree pollen concentration of 1 week prior (adj R²=0.2280). O₃ concentration was correlated to the number of viral infections within that week (adj R²=0.2552) in spring, and weed pollen and CO concentration correlated (adj R²=0.1327) in autumn.

CONCLUSIONS

Seasonal co-exposure to air pollutants and allergenic pollens may enhance respiratory viral infection susceptibility in children. Therefore, reducing the concentrations of air pollutants and pollens may help prevent future epidemics.

The relationship between mothers' knowledge and practice level of cough etiquette and their children's practice level in South Korea

Purpose

This study investigated the relationships between mothers' knowledge and practice level of cough etiquette and their children's practice level of cough etiquette as perceived by their mothers.

Methods

This study was a descriptive correlational study. The data were collected from 160 mothers with preschoolers attending daycare centers and kindergartens in Gwangju, South Korea using self-reported questionnaires.

Results

The correct answer rate for cough etiquette knowledge in mothers was 86.0%, mothers' average practice score was 33.65±4.14, and their children's average practice score was 28.39±4.85 out of 48. The correlation between mothers' cough etiquette knowledge and practice level was not statistically significant. However, mothers' cough etiquette practice was positively correlated with children's cough etiquette level as perceived by mothers (r=.35, p<.001).

Conclusion

The development of a systematic cough etiquette education program and measurements for both mothers and children according to their developmental stages is important to effectively prevent respiratory infections.

Human respiratory syncytial virus: prevalence, viral co-infections and risk factors for lower respiratory tract infections in children under 5 years of age at a general hospital in the Democratic Republic of Congo

PURPOSE

This study aimed to determine the prevalence of human respiratory syncytial virus (HRSV) acute respiratory infection (ARI) in children under the age of 5 years at the Provincial General Hospital of Bukavu (PGHB), and to analyse factors associated with the risk of ARI being diagnosed as lower respiratory tract infection (LRTI).

METHODOLOGY

A total of 146 children under 5 years visiting the PGHB for ARI between August and December 2016 were recruited, and socio-demographic information, clinical data and nasopharyngeal swabs were collected. The samples were analysed by a multiplex reverse transcriptase polymerase chain reaction targeting 15 different viruses.

RESULTS

Of 146 samples collected, 84 (57.5 %) displayed a positive result of at least one of the 15 viruses. The overall prevalence of HRSV was 21.2 %. HRSV A (30, 20.5 %) was the virus the most detected, followed by HRV (24, 16.4 %), PIV3 (20, 16.6) and ADV (7, 4.79 %). The other viruses were detected in three or fewer cases. There were only 11 (7.5 %) cases of co-infection. HRSV infection, malnutrition, younger age, rural settings, low income and mother illiteracy were associated with the risk of ARI being diagnosed as LRTI in bivariate analyses but, after adjusting for the confounding factors, only HRSV infection and younger age were independently associated with LRTI.

CONCLUSION

The prevalence of HRSV is high among children visiting the PGHB for ARI. HRSV infection and lower age are independently associated with the risk of ARI being diagnosed as LRTI.

Clinical Impact of Mixed Respiratory Viral Infection in Children with Adenoviral Infection

Background

Although adenovirus (ADV) infection occurs steadily all year round in Korea and the identification of respiratory viral coinfections has been increasing following the introduction of multiplex real-time polymerase chain reaction tests, the clinical impact of viral coinfection in children with ADV infection has rarely been reported.

Materials and Methods

Medical records of children diagnosed with ADV infection were retrospectively reviewed. The enrolled children were divided into two groups based on the identified respiratory viruses: ADV group and coinfection group. Clinical and laboratory parameters were compared between the two groups.

Results

In total, 105 children (60 males and 45 females) with a median age of 29 months (range: 0-131 months) diagnosed with an ADV infection were enrolled. Fever (99.0%) was by far the most frequent symptom, followed by respiratory (82.9%), and gastrointestinal (22.9%) symptoms. Upper and lower respiratory tract infections were diagnosed in 56 (53.3%), and 32 (30.5%) children, respectively. Five (4.8%) children received oxygen therapy, and no child died due to ADV infection. Coinfection was diagnosed in 32 (30.5%) children, with rhinovirus (46.9%), and respiratory syncytial virus (21.9%) being the most frequent. The proportions of children younger than 24 months (P <0.001), with underlying medical conditions (P = 0.020), and diagnosed with lower respiratory tract infection (P = 0.011) were significantly higher in the coinfection group than in the ADV group. In a multivariate analysis, only the younger age was significantly associated with coinfection (P <0.001). Although more children in the coinfection group received oxygen therapy (P = 0.029), the duration of fever and hospitalization was not significantly different between the two groups.

Conclusion

Respiratory viral coinfection with ADV occurred more frequently in children younger than 24 months of age compared with children aged 24 months or older. Respiratory viral coinfection may increase the severity of ADV infection, however, appropriate therapy prevented prolonged hospitalization and poor prognosis due to coinfection.

Hospitalization for Influenza A Versus B

BACKGROUND

The extent to which influenza A and B infection differs remains uncertain.

METHODS

Using active surveillance data from the Canadian Immunization Monitoring Program Active at 12 pediatric hospitals, we compared clinical characteristics and outcomes of children ≤16 years admitted with laboratory-confirmed influenza B or seasonal influenza A. We also examined factors associated with ICU admission in children hospitalized with influenza B.

RESULTS

Over 8 nonpandemic influenza seasons (2004-2013), we identified 1510 influenza B and 2645 influenza A cases; median ages were 3.9 and 2.0 years, respectively (P < .0001). Compared with influenza A patients, influenza B patients were more likely to have a vaccine-indicated condition (odds ratio [OR] = 1.30; 95% confidence interval [CI] = 1.14-1.47). Symptoms more often associated with influenza B were headache, abdominal pain, and myalgia (P < .0001 for all symptoms after adjustment for age and health status). The proportion of deaths attributable to influenza was significantly greater for influenza B (1.1%) than influenza A (0.4%); adjusted for age and health status, OR was 2.65 (95% CI = 1.18-5.94). A similar adjusted OR was obtained for all-cause mortality (OR = 2.95; 95% CI = 1.34-6.49). Among healthy children with influenza B, age ≥10 years (relative to <6 months) was associated with the greatest odds of ICU admission (OR = 5.79; 95% CI = 1.91-17.57).

CONCLUSIONS

Mortality associated with pediatric influenza B infection was greater than that of influenza A. Among healthy children hosptialized with influenza B, those 10 years and older had a significant risk of ICU admission.

Parainfluenza Virus Infection

Human parainfluenza viruses (HPIVs) are single-stranded, enveloped RNA viruses of the Paramyoviridaie family. There are four serotypes which cause respiratory illnesses in children and adults. HPIVs bind and replicate in the ciliated epithelial cells of the upper and lower respiratory tract and the extent of the infection correlates with the location involved. Seasonal HPIV epidemics result in a significant burden of disease in children and account for 40% of pediatric hospitalizations for lower respiratory tract illnesses (LRTIs) and 75% of croup cases. Parainfluenza viruses are associated with a wide spectrum of illnesses which include otitis media, pharyngitis, conjunctivitis, croup, tracheobronchitis, and pneumonia. Uncommon respiratory manifestations include apnea, bradycardia, parotitis, and respiratory distress syndrome and rarely disseminated infection. Immunity resulting from disease in childhood is incomplete and reinfection with HPIV accounts for 15% of respiratory illnesses in adults. Severe disease and fatal pneumonia may occur in elderly and immunocompromised adults. HPIV pneumonia in recipients of hematopoietic stem cell transplant (HSCT) is associated with 50% acute mortality and 75% mortality at 6 months. Though sensitive molecular diagnostics are available to rapidly diagnose HPIV infection, effective antiviral therapies are not available. Currently, treatment for HPIV infection is supportive with the exception of croup where the use of corticosteroids has been found to be beneficial. Several novel drugs including DAS181 appear promising in efforts to treat severe disease in immunocompromised patients, and vaccines to decrease the burden of disease in young children are in development.

Evaluation of case definitions for estimation of respiratory syncytial virus associated hospitalizations among children in a rural community of northern India

BACKGROUND

The burden estimation studies for respiratory syncytial virus (RSV) have been based on varied case definitions, including case-definitions designed for influenza surveillance systems. We used all medical admissions among children aged 0-59 months to study the effect of case definitions on estimation of RSV-associated hospitalizations rates.

METHODS

The hospital-based daily surveillance enrolled children aged 0-59 months admitted with acute medical conditions from July 2009-December 2012, from a well-defined rural population in Ballabgarh in northern India. All study participants were examined and nasal and throat swabs taken for testing by real-time polymerase chain reaction (RT-PCR) for RSV and influenza virus. Clinical data were used to retrospectively evaluate World Health Organization (WHO) case definitions (2011) commonly used for surveillance of respiratory pathogens, ie, acute respiratory illness (WHO-ARI), severe ARI (SARI) and influenza-like illness (ILI), for determination of RSV-associated hospitalization. RSV-associated hospitalization rates adjusted for admissions at non-study hospitals were calculated.

FINDINGS

Out of 505 children enrolled, 82 (16.2%) tested positive for RSV. Annual incidence rates of RSV-associated hospitalization per 1000 children were highest among infants aged 0-5 months (15.2; 95% confidence interval (CI) 8.3-26.8), followed by ages 6-23 months (5.3, 95% CI 3.2-8.7) and lowest among children 24-59 months (0.5, 95% CI 0.1-1.5). The RSV positive children were more likely to have signs of respiratory distress like wheeze, chest in-drawing, tachypnea, and crepitation compared to RSV-negative based on bivariate comparisons. Other less commonly seen signs of respiratory distress, ie, nasal flaring, grunting, accessory muscle usage were also significantly associated with being RSV positive. Compared to the estimated RSV hospitalization rate based on all medical hospitalizations, the WHO-ARI case definition captured 86% of the total incidence, while case definitions requiring fever like ILI and SARI underestimated the incidence by 50-80%.

CONCLUSIONS

Our study suggests that RSV is a substantial cause of hospitalization among children aged <24months especially those aged <6 months. The WHO-ARI case definition appeared to be the most suitable screening definition for RSV surveillance because of its high sensitivity.

Characterization of acute respiratory infections among 340 infants in Wuxi, Jiangsu Province

BACKGROUND

To investigate the etiological and epidemiological features of acute respiratory infections among children in Wuxi, Jiangsu Province.

METHODS

Nasopharyngeal swab specimens were collected from 340 pediatric patients from Wuxi Second People's Hospital from June 2012 to May 2014. Seven respiratory viruses including influenza virus A (FA), influenza virus B (FB), parainfluenza virus I (PIVI), parainfluenza virus II (PIVII), parainfluenza virus III (PIVIII), adenovirus (ADV), and respiratory syncytial virus (RSV) were detected using direct immunofluorescence method. Epidemiological analysis was performed in terms of gender, age, and seasonal distribution.

RESULTS

Among these 340 patients, viral pathogens were detected in 116 cases (34.12%), with the leading three viruses being RSV (16.18%; 55/340), FB (5.29%; 18/340), and FA (5.00%; 17/340). The positive rate was not significantly different between male (36.32%; 73/201) and female (31.65%; 44/139) patients (P>0.05). The positive rate was highest in the 0-1-year-old group (48.48%; 32/66) and in winter (42.72%; 44/103).

CONCLUSIONS

RSV is the most commonly detected respiratory virus in Wuxi. Infants aged 0-1 year should be a priority population during disease prevention and control. Respiratory infections among children are more common in winter.

Seasonal Variation in Flares of Intestinal Behçet's Disease

BACKGROUND

There have been numerous investigations into the seasonality of several autoimmune diseases and inflammatory bowel disease in an effort to better understand the epidemiology and pathogenesis of these conditions. However, the relationship between the season and disease activity of intestinal Behçet's disease has not been investigated.

AIMS

This study aimed to evaluate the seasonal pattern of exacerbations of intestinal Behçet's disease.

METHODS

We evaluated 268 consecutive patients with intestinal Behçet's disease who were diagnosed and treated between November 1990 and March 2010 at Severance Hospital, Yonsei University, Seoul, Korea. Patient demographics, onset of symptoms, total number of relapses, and the month of each relapse were recorded. The relationship between the season and flares of intestinal Behçet's disease was analyzed.

RESULTS

A total of 339 relapses occurred in 142 patients (53 %). The median age at diagnosis was 39 (10-73) years; the median follow-up duration was 74 (7-372) months. The peak seasons for relapse were spring and autumn, especially the months of May and September (p value <0.001). Compared with winter, spring and autumn had higher rates of flares (HR 1.92 and 1.91, respectively, p value <0.001).

CONCLUSIONS

In this study, intestinal Behçet's disease demonstrated a biphasic pattern (peaks in spring and autumn) in exacerbations of disease, suggesting that seasonal or exogenous factors may be involved in the flares of intestinal Behçet's disease.

Prevalence and correlation of infectious agents in hospitalized children with acute respiratory tract infections in Central China

Acute respiratory tract infections (ARTIs) are associated with significant morbidity and mortality worldwide, especially in children under the age of 5 years. Almost 2 million children die from ARTIs each year, and most of them are from developing countries. The prevalence and correlation of pathogens in ARTIs are poorly understood, but are critical for improving case prevention, treatment, and management. In this study, we investigated the prevalence and correlation of infectious agents in children with ARTIs. A total of 39,756 children with one or more symptoms, including fever, cough, sore throat, tonsillitis, pharyngitis, herpangina, pneumonia, and bronchiolitis, were enrolled in the study. All patients were hospitalized in Wuhan Children’s Hospital between October 1, 2010 and September 30, 2012, and were evaluated for infectious agents. Pathogens, including Mycoplasma pneumoniae, influenza A virus, influenza B virus, adenoviruses, respiratory syncytial virus, parainfluenza virus, Legionella pneumophila, Chlamydophila pneumoniae, and Coxiella burnetii, were screened simultaneously in patient blood samples using anti-pathogen IgM tests. Regression analysis was used to reveal correlations among the pathogens. Our results showed that one or more pathogens were identified in 10,206 patients, and that Mycoplasma pneumoniae, adenoviruses, and influenza B virus were the leading infectious agents. Mixed-infections of pathogens were detected in 2,391 cases, with Mycoplasma pneumoniae as the most frequent pathogen. The most common agents in the co-infections were Mycoplasma pneumoniae and influenza B virus. Regression analysis revealed a linear correlation between the proportion of mixed infections and the incidence of multi-pathogen infections. The prevalence of infectious agents in children with ARTIs was determined. Equations were established to estimate multiple infections by single-pathogen detection. This revealed a linear correlation for pathogens in children with ARTIs. This study provides useful information for improving case prevention and management.

Genetic analysis of human parainfluenza viruses circulating in Korea, 2006

Human parainfluenza viruses (HPIV) are important causes of respiratory tract infections in young children. To characterize the molecular epidemiology of an HPIV outbreak occurring in Korea during 2006, genetic analysis of 269 cell culture isolates from HPIV-infected children, was conducted using nested reverse transcription-PCR (RT-PCR). HPIV-1 was detected in 70.3% of tested samples (189/269). The detection rate of HPIV-2 and HPIV-3 was 1.5% (4/269) and 9.3% (25/269), respectively. Mixed HPIV-1, -2 and -3 infections were detected in 19.0% (51/269): HPIV-1 and HPIV-2 in 15, HPIV-1 and HPIV-3 in 26, HPIV-2 and HPIV-3 in 6, and HPIV-1, -2 and -3 in 4. Of these positive samples for three different types HIPV-1, -2, and -3, two each representative strains were selected, the full length of hemagglutinin-neuraminidase (HN) gene for HPIV was amplified by RT-PCR, and sequenced. Multiple alignment analysis, based on reference sequence of HPIV-1, -2, and -3 strains available in GenBank, showed that the identity of nucleotide and deduced amino acid sequences was 92.4-97.6% and 92.7-97.9%, respectively, for HPIV-1, 88.5-99.8% and 88.6-100% for HPIV-2, and 96.3-99.5% and 95.0-99.3% for HPIV-3, respectively. Phylogenetic analysis showed that HPIV-1, -2, and -3 strains identified in this study were closely related among the strains in the same type with no significant genetic variability. These results show that HPIV of multiple imported sources was circulating in Korea.

Seasonal variation in months of birth and symptom flares in Korean patients with inflammatory bowel disease

Background/Aims

Seasonal variation may influence the development and exacerbation of inflammatory bowel disease (IBD). However, most epidemiologic studies on this topic have been conducted in Western countries. The purpose of this study was to determine whether birth dates and symptom flares follow a seasonal pattern in Korean patients with IBD.

Methods

Patients with a diagnosis of IBD established between January 2003 and December 2010 were investigated at six university hospitals in Korea. The expected births and flares, with a uniform distribution during the year and considering differences in the number of days in the months of 1 year, were calculated.

Results

A total of 411 patients with ulcerative colitis (UC) and 316 patients with Crohn disease (CD) were included in the study. Birth during the winter period, and especially in January and February, was associated with an increased risk of IBD, especially in UC patients. The symptom flares of CD patients occurred most frequently in the spring, with a nadir in the autumn. However, no disease flare seasonality was noted for UC patients.

Conclusions

Our data suggest that seasonally varying environmental factors during pregnancy and the postpartum period are associated with a susceptibility to IBD later in life and that exacerbations of CD are influenced by seasonal factors.

The burden of influenza B: a structured literature review

We reviewed the epidemiology, clinical characteristics, disease severity, and economic burden of influenza B as reported in the peer-reviewed published literature. We used MEDLINE to perform a systematic literature review of peer-reviewed, English-language literature published between 1995 and 2010. Widely variable frequency data were reported. Clinical presentation of influenza B was similar to that of influenza A, although we observed conflicting reports. Influenza B-specific data on hospitalization rates, length of stay, and economic outcomes were limited but demonstrated that the burden of influenza B can be significant. The medical literature demonstrates that influenza B can pose a significant burden to the global population. The comprehensiveness and quality of reporting on influenza B, however, could be substantially improved. Few articles described complications. Additional data regarding the incidence, clinical burden, and economic impact of influenza B would augment our understanding of the disease and assist in vaccine development.

Comparison of diagnostic tools with multiplex polymerase chain reaction for pediatric lower respiratory tract infection: a single center study

BACKGROUND/PURPOSE

Acute respiratory tract infections are a leading cause of morbidity and mortality in children worldwide. Most have a viral etiology, with pneumococcus as an important pathogen. This single-center study compared the use of conventional diagnostic tools and two multiplex polymerase chain reaction (PCR) examinations for determining pathogens in lower respiratory tract infections (LRTIs) among children aged <5 years.

METHODS

From July to October 2010, 45 patients aged 2 months to 60 months and diagnosed as having LRTIs were enrolled. Their nasopharyngeal aspirates were evaluated through viral culture and two multiplex PCR examinations. The patients' clinical course, symptoms, signs, and laboratory findings were recorded and analyzed.

RESULTS

Among the 45 patients, 38 (84.4%) had detectable pathogens. Conventional viral and blood cultures had 35.6% positive rate, which increased to 51.1% when the quick antigen tests (Influenza A+B test and respiratory syncytial virus) and urine pneumococcal antigen test were combined. The positive rate further increased to 84.4% when the two multiplex PCR methods were combined. Twelve patients had co-infection, including 10 detected by the multiplex PCR methods. The co-infection rate was 26.7% (12/45).

CONCLUSION

Most LRTIs in children have a viral etiology. Multiplex PCR tests are rapid assays that can increase the diagnostic yield rate and detect slow-growing viruses and can detect more pathogens than conventional viral culture to enable, thereby helping clinicians to provide appropriate and timely treatment.

Adenovirus infection with serious pulmonary sequelae in Korean children

INTRODUCTION

Varying clinical progress and long-term pulmonary sequelae have been associated with different adenoviral serotypes.

OBJECTIVE

The purpose of this study was to determine the association between serotype and clinical profiles of pediatric adenoviral pneumonia cases that occurred in Korea from 1996-1998.

METHODS

Nasopharyngeal aspirate samples from 44 adenovirus-positive patients presenting with acute severe respiratory disease were sent to reference laboratories for serotyping. Clinical course and chest X-rays were analyzed during the acute phase, and HRCTs were performed during the convalescent phase to identify long-term pulmonary complications.

RESULTS

Ad-7 was associated with the most severe clinical course and resultant long-term pulmonary sequelae, followed by milder clinical course and lower frequency of sequelae in Ad-3 cases, and even milder outcomes in children infected with Ad-5.

CONCLUSIONS

In complicated adenoviral pneumonia, certain serotypes prevail with Ad-7 being the most severe. Continued serotyping with the eventual goal of creating a database for the early diagnosis, treatment and prognostication of adenoviral pneumonia is needed.

Newly identified respiratory viruses associated with acute lower respiratory tract infections in children in Lanzou, China, from 2006 to 2009

Nasopharyngeal aspirates were collected from 813 children ≤ 14 years old with acute lower respiratory tract infections in Lanzhou, China, from December 2006 to November 2009. PCR or RT-PCR was used to screen for the presence of 10 respiratory viruses. Viral agents were identified in 73.92% (601/813) of specimens, including RSV in 40.71%, hMPV in 6.15%, IFVA in 7.13%, IFVB in 0.98%, PIV1-3 in 7.87%, HCoV-HKU1 in 2.21%, HCoV-NL63 in 3.81%, HRV in 19.93%, AdV in 7.50% and HBoV in 11.56%. Two or more viruses were detected in 34.44% (280/813) of cases. The newly identified respiratory viruses, HBoV, hMPV, HCoV-HKU1 and HCoV-NL63, accounted for 22.01% of the detected viral pathogens. RSV and HRV were frequently detected in patients with bronchiolitis, and hMPV was frequently associated with pneumonia. HCoV-NL63 was found to be one of the causative agents of acute respiratory wheezing in young children. No seasonal variation was found in the incidence of detection of HCoV-HKU1, HCoV-NL63 or HBoV. This 3-year study demonstrated that viral pathogens play an important role in children with ALRTIs, and more attention should be paid to these newly identified viral agents.

A naturally occurring human adenovirus type 7 variant with a 1743 bp deletion in the E3 cassette

Human adenovirus type 7 (HAdV-7) is an important cause of acute respiratory disease (ARD). Different genomic variants of HAdV-7 have been described, designated 7a-7l. In a previous study to investigate risk factors for ARD and wheezing, nasopharyngeal samples were collected from 90 ill children seeking medical attention in Ribeirão Preto, São Paulo, Brazil. HAdVs were identified in 31 samples and were characterized by serum neutralization and genome restriction analysis. Eleven HAdVs were identified as being HAdV-7, five of which were classified as being of genome type 7p (Gomen). Six other HAdV-7 isolates gave new restriction profiles with all enzymes used and were classified as being a new genomic variant, 7m. These isolates were further characterized by sequencing. The hexon and fiber genes of the 7m variant were nearly identical to the prototype, 7p. However, nucleotide sequences from the E3 cassette revealed a 1743 bp deletion affecting the 16.1K, 19K, 20.1K and 20.5K ORFs.

Outcomes of palivizumab prophylaxis for respiratory syncytial virus infection in preterm children with bronchopulmonary dysplasia at a single hospital in Korea from 2005 to 2009

This study was performed to evaluate the utilization and outcomes of palivizumab in high risk children born prematurely with chronic lung disease (CLD). A retrospective review of 128 patients was conducted from September 2004 to March 2009 at the Ajou University Hospital. All patients were diagnosed with CLD, were born at Collapse

Key Words

• Chronic Lung Disease
• Hospitalization
• Palivizumab Prophylaxis, Respiratory Syncytial Viruses
• Preterm Children

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MESH Headings

• Antibodies, Monoclonal/therapeutic use
• Antibodies, Monoclonal, Humanized
• Antiviral Agents/therapeutic use
• Bronchopulmonary Dysplasia/complications
• Bronchopulmonary Dysplasia/diagnosis
• Demography
• Hospitalization
• Humans
• Infant
• Infant, Newborn
• Palivizumab
• Premature Birth
• Republic of Korea
• Respiratory Syncytial Virus Infections/complications
• Respiratory Syncytial Virus Infections/prevention & control
• Retrospective Studies
• Risk Factors
• Treatment Outcome

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Affiliation(s)

Seung Gu Chang Department of Pediatric, Ajou University School of Medicine, Suwon, Korea
Moon Sung Park Department of Pediatric, Ajou University School of Medicine, Suwon, Korea
Jae Eun Yu Department of Pediatric, Ajou University School of Medicine, Suwon, Korea

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The burden of influenza in East and South-East Asia: a review of the English language literature

Abstract  While human infections with avian influenza A (H5NI) viruses in Asia have prompted concerns about an influenza pandemic, the burden of human influenza in East and Southeast Asia has received far less attention. We conducted a review of English language articles on influenza in 18 countries in East and Southeast Asia published from 1980 to 2006 that were indexed on PubMed. Articles that described human influenza‐associated illnesses among outpatients or hospitalized patients, influenza‐associated deaths, or influenza‐associated socioeconomic costs were reviewed. We found 35 articles from 9 countries that met criteria for inclusion in the review. The quality of articles varied substantially. Significant heterogeneity was noted in case definitions, sampling schemes and laboratory methods. Early studies relied on cell culture, had difficulties with specimen collection and handling, and reported a low burden of disease. The recent addition of PCR testing has greatly improved the proportion of respiratory illnesses diagnosed with influenza. These more recent studies reported that 11–26% of outpatient febrile illness and 6‐14% of hospitalized pneumonia cases had laboratory‐confirmed influenza infection. The influenza disease burden literature from East and Southeast Asia is limited but expanding. Recent studies using improved laboratory testing methods and indirect statistical approaches report a substantial burden of disease, similar to that of Europe and North America. Current increased international focus on influenza, coupled with unprecedented funding for surveillance and research, provide a unique opportunity to more comprehensively describe the burden of human influenza in the region.

Comparison of cytokine responses in nasopharyngeal aspirates from children with viral lower respiratory tract infections

Aim: To determine whether nasopharyngeal aspirates (NPAs) cytokine response is different according to the causative viruses in children with lower respiratory tract infections (LRTI).

Methods: NPAs from 277 children with LRTI caused by respiratory virus were evaluated. Based on the proven viral agents, LRTI patients were divided into four groups. Levels of IL‐4, IL‐5 and IFN‐γ were determined by ELISA.

Results: Patients with influenza virus infection demonstrated significantly lower IL‐4 and IL‐5 levels than those with other three groups. Patients with respiratory syncytial virus (RSV) infection showed an increase in production of IL‐4 and IL‐5, and a decrease in the IFN‐γ level when compared to patients with influenza virus infection. Interestingly, a similar Th2 response was seen in patients with parainfluenza virus or adenovirus infection.

Conclusion: These results demonstrate that respiratory viruses can induce different local cytokine responses. However, Th2 biased responses are not unique for RSV but seem to be predominant in respiratory viruses of young children.

Burden of viral respiratory disease hospitalizations among children in a community of Seoul, Republic of Korea, 1995 - 2005

Our objective was to describe respiratory disease hospitalizations among children in a community of Seoul, Republic of Korea. Discharge data (January 1995-December 2005) from Guro Hospital (Seoul, Republic of Korea) were collected from the hospital medical records office. Respiratory virus test results (March 2004-December 2005) and hospitalization charges to the National Health Insurance Corporation (January 2002-December 2005) were provided by hospital laboratory and administrative departments. Variations in hospitalizations, test results and total hospitalization-associated medical charges were described by age, clinical complaint, discharge month and length of stay. Over the 11-y period, 4247 paediatric hospitalizations for lower respiratory disease occurred. Semi-annual epidemics were identified in October-December and April-May. Among a subset (n=400) of patients, 48% had respiratory syncytial virus, 16% parainfluenza virus, 19% influenza viruses and 17% adenovirus infection. On admission, children had respiratory problems (53%), fever (39%), or other systemic problems (8%). The median charge of a lower respiratory disease hospitalization was highest in January ($1334) and lowest in October ($1076). Median hospitalization charges were highest among children 8-15 years of age compared with younger children </=2 years and those 3-7 years of age. Respiratory disease hospitalizations among children demonstrated annual variations reflecting patterns of children with laboratory-confirmed respiratory viral infections. In the Republic of Korea, prospective studies that use standardized laboratory testing for respiratory pathogens in children will help to estimate the total burden of viral lower respiratory tract disease.

Influenza A and respiratory syncytial virus hospital burden in young children in East London

Epidemiological studies have demonstrated high hospitalization rates attributable to influenza and RSV in children aged 6 months and those aged <12 months, respectively (43 and 92.5/10 000 person-months, respectively). In conclusion, these high paediatric RSV and influenza incidence rates can be used to inform UK policy on childhood influenza immunization and subsequent RSV immunization in the future.

High isolation rate of adenovirus serotype 7 from South Korean military recruits with mild acute respiratory disease

Adenovirus is a major cause of acute respiratory disease (ARD) in military recruits. When South Korean military recruits with ARD were surveyed, adenovirus was identified in 122 (61.0%) of the 200 recruits studied. Moreover, all cases of ARD involving adenovirus were caused by serotype 7.

Finnish adenoidectomy and tympanostomy rates in children; national variation

OBJECTIVES

To assess upper respiratory surgery rates in Finnish children and compare the rates of adenoidectomy and tympanostomy tubes in 2002 with the 1987 cohort.

METHODS

Descriptive study of national upper respiratory surgery in Finland in 1987 and 2002; adenoidectomies, tympanostomy tubes and combination of these two. Surgical rates were viewed in the light of child density and number of primary care physicians and otorhinolaryngologists.

RESULTS

Rates of adenoidectomy and tympanostomy tubes were highest in Western Finland and lowest in Eastern Finland (p<0.00001). Peak-age for adenoidectomy and tympanostomy tubes was in the second year of life. Surgery was most common in boys (p<0.00001). Both the numbers of otorhinolaryngologists and operations increased from 1987 to 2002; the largest surgery increase, 7.3%, was found in Western Finland.

CONCLUSION

Large national differences in rates of paediatric adenoidectomy and tympanostomy tubes in Finland propose that national guidelines have not had an impact on the selection of children for surgery.

Epidemiology and clinical characteristics of respiratory syncytial virus infections in Jordan

This study was carried out to determine the prevalence, seasonal distribution of RSV, the signs and symptoms associated with it in Jordan. A total of 200 nasopharyngeal aspirates were obtained from hospitalized children (below 2 years old). RSV was detected in 12.5% of patients using direct immunofluorescence technique. Most infections were associated with bronchilolitis, and higher rates of hypoxemia, retractions, tachypnea, hyperinflation and interstitial infiltrates in 1 to 3 months old children. RSV showed a clear temporal periodicity. The epidemic began in December and disappeared in March with a peak of incidence during February 2003 and January 2004. The seasonal distribution showed a significant correlation with temperature, rainfall and relative humidity. This study provides further information on RSV epidemiology which could help in planning of prevention and control programs in Jordan, distinguishing RSV infections on the basis of the clinical picture and considering RSV between December and March each year.

Is influenza vaccination in asthmatic children helpful?

The rationale for influenza vaccination in asthmatic children theoretically lies in prevention of exacerbations and serious complications like pneumonia. Solid evidence from randomized clinical trials of its preventive effects on these clinical endpoints is, however, lacking. Nevertheless, most Western guidelines advise to vaccinate these children. In the real life situation this advice isn't very well followed: vaccine coverage for this indication is low. To assess the usefulness of influenza vaccination in children with asthma a set of fundamental questions regarding this activity is presented and answered. This leads to the conclusion that, given the evidence, influenza vaccination in children with mild to moderate disease should be reconsidered.

Frequency of detection of picornaviruses and seven other respiratory pathogens in infants

BACKGROUND

Previous studies in which molecular-based techniques have been used to identify the causative pathogens of respiratory tract infection have investigated hospitalized children only. We report a prospective study designed to determine the frequency and clinical presentation of community-acquired respiratory illness in infancy associated with 8 common respiratory pathogens.

METHODS

Eighty-eight infants were monitored through their first winter. With each respiratory illness, infants were examined, and a nasal lavage specimen was collected. Individual reverse transcription-polymerase chain reactions were performed to detect infection with picornaviruses (rhinoviruses and enteroviruses), coronaviruses (serotypes OC43 and 229E), adenoviruses, parainfluenza viruses 1-3, influenza viruses (types A and B), respiratory syncytial virus (RSV), Chlamydia pneumoniae and Mycoplasma pneumoniae.

RESULTS

Picornaviruses were the most frequently detected pathogen identified in 46% (56 of 123) of episodes, followed by RSV (27%), parainfluenza viruses (13%) and coronaviruses (9%). Dual pathogen infections were identified in 20% of episodes, predominantly caused by picornaviruses together with either RSV or parainfluenza viruses. RSV infection was significantly associated with a diagnosis of bronchiolitis. No other associations were found between pathogen and clinical diagnosis. Dual infection did not predispose infants to a more severe clinical course.

CONCLUSIONS

Picornaviruses are the predominant cause of community-acquired respiratory tract infection in the first year of life. Large prospective community-based studies will be needed to fully evaluate the contribution of picornaviruses, both in isolation and in combination with other respiratory pathogens, to the various clinical syndromes of respiratory infection observed during infancy.

Viral respiratory infection in Curitiba, Southern Brazil

OBJECTIVE

Viral infection is the major cause of respiratory tract pathology affecting individuals of all ages, especially children and immunocompromised patients. There is a paucity of data on etiological and epidemiological infection caused by virus, in Southern Brazil. The aim of this study was to evaluate the seasonality, and the incidence of the viruses involved in respiratory infections in Curitiba, South Brazil.

METHODS

Two hundred seventy-three nasopharyngeal aspirates (NPA) from primary care health units and 1348 NPA or bronchoalveolar lavages from a tertiary-care teaching hospital were studied. Viruses were identified by indirect immunofluorescence and cellular culture.

RESULTS

Thirty percent of tested samples scored positive for the presence of virions. The percentages of infection for each virus from outpatients and hospitalized, respectively, were 3.3, 19.3 for respiratory syncytial virus; 13.9, 3.5 for influenza A, 3.0, 1.7 for influenza B; 3.3, 5.6 for parainfluenza virus and 2.2, 0.8 for adenovirus. A higher incidence of positive results was found during the winter season, thus showing a pattern of seasonality.

CONCLUSION

Viral agents are one of the main etiologies of respiratory tract pathology in the population studied.

Incidence of influenza and associated illness in children aged 0-19 years: a systematic review

A systematic review was conducted to estimate the incidence of influenza and concomitant morbidity and mortality in children from 0 to 19 years (0-19 years). Medline was searched for observational studies and placebo or non-treated arms of experimental studies providing occurrence rates of laboratory-proven influenza illness. From the 2758 titles identified, 356 full papers were reviewed based on the abstract or title; after searching their reference lists an additional 16 papers were found. Finally 28 studies met our inclusion criteria, reporting a varying seasonal incidence of influenza of up to 46%. However, when analysing two long-term observational studies and averaging seasonal fluctuations, the overall incidence of influenza was found to range from 5% to 9.5% per year. Serious morbidity was seldom reported and no cases of mortality were found. Our review shows influenza as an infection with a moderate average incidence and a self-limiting character that is associated with mild morbidity and rare cases of mortality in children. This systematic review may be subject to two contrasting biases. First, the limited number of children reported in the literature with proven influenza infections would tend to under-represent the incidence of uncommon but serious complications such as death. Second, the preferential reporting of influenza outbreak seasons may over-estimate the importance of influenza. Future population based studies should focus on consecutive influenza seasons and capture indirect benefits of vaccinations such as interruption of transmission in the community so that preventive strategies for children can be reconsidered with special attention to their cost effectiveness.

Respiratory viruses seasonality in children under five years of age in Buenos Aires, Argentina: a five-year analysis

OBJECTIVES

During the winter months there is a remarkable increase in paediatric hospitalisations due to viral acute lower respiratory infections (ALRI). We aimed to perform a five-year retrospective analysis (1998-2002) of ALRI viral aetiology in children under 5 years of age admitted to public hospitals in Buenos Aires city to evaluate its seasonality.

MATERIALS AND METHODS

Nasopharyngeal aspirates (NPA) were analysed by indirect immunofluorescence to determine viral aetiology. A Spearman's rank correlation test between meteorological parameters and viral frequencies was performed.

RESULTS

Viruses were identified in 6083 (32.8%) of 18,561 NPA tested. Among the former 4796 (78.8%) were RSV, 508 (8.3%) IA, 473 (7.8%) AV, 293 (4.8%) PIV and 13 (0.2%) IB. RSV and IA peaked during the coldest and dampest months, whereas PIV did so in early spring and AV lasted throughout the year. For RSV and IA an inverse correlation with mean monthly temperature (r = -0.9 and r = -0.87, respectively, p<0.0001) and solar UVB radiation (r = -0.92 and r = -0.80, respectively, p<0.0001) was detected, while it was positive when relative humidity was considered (r = 0.6, p<0.0001 and r = 0.47, p=0.0068, respectively).

CONCLUSIONS

This study highlights the seasonal variation of ALRI and allows the implementation of adequate healthcare strategies and practice guidelines.

Parainfluenza viruses

Human parainfluenza viruses (HPIV) were first discovered in the late 1950s. Over the last decade, considerable knowledge about their molecular structure and function has been accumulated. This has led to significant changes in both the nomenclature and taxonomic relationships of these viruses. HPIV is genetically and antigenically divided into types 1 to 4. Further major subtypes of HPIV-4 (A and B) and subgroups/genotypes of HPIV-1 and HPIV-3 have been described. HPIV-1 to HPIV-3 are major causes of lower respiratory infections in infants, young children, the immunocompromised, the chronically ill, and the elderly. Each subtype can cause somewhat unique clinical diseases in different hosts. HPIV are enveloped and of medium size (150 to 250 nm), and their RNA genome is in the negative sense. These viruses belong to the Paramyxoviridae family, one of the largest and most rapidly growing groups of viruses causing significant human and veterinary disease. HPIV are closely related to recently discovered megamyxoviruses (Hendra and Nipah viruses) and metapneumovirus.

Respiratory syncytial virus epidemics: the ups and downs of a seasonal virus

Respiratory syncytial virus (RSV) is the most common pathogen causing lower respiratory tract infections in infants worldwide. Lower respiratory tract infections caused by RSV occur epidemically, and the appearance of epidemics seems to vary with latitude, altitude and climate. This study uses a review of the literature on RSV seasonality to investigate whether a global pattern in RSV epidemics can be found. A comparison of morbidity and mortality caused by RSV in developed vs. developing countries is also presented. The seasons in which RSV epidemics occur typically depend on geographic location and altitude. During these seasons the epidemics tend to appear in clusters. Although the appearance pattern of these epidemics varies from one continent to another, they usually begin in coastal areas. RSV is the cause of one-fifth of lower respiratory infections worldwide. Generally RSV mortality is low, with a median value of zero. However, RSV mortality in developing countries is significantly higher than RSV mortality in developed countries.

Bedside diagnosis of influenzavirus infections in hospitalized children

OBJECTIVE

For preventing nosocomial influenza infections and to facilitate prompt antiviral therapy, an accessible, rapid diagnostic method for influenzavirus is needed. We evaluated the performance of a lateral-flow immunoassay (QuickVue Influenza Test) completed at the bedside of hospitalized children during the influenza season.

METHODS

All children who were evaluated at a large teaching hospital during the 1999 to 2000 influenza season were eligible if they were 1) younger than 19 years and hospitalized with respiratory symptoms or 2) younger than 3 years and hospitalized with fever. Each study child had 2 nasal swabs obtained--1 for influenzavirus culture and polymerase chain reaction (PCR) and the other for the QuickVue Influenza Test. The performance of the rapid diagnostic test was compared with the results of culture or PCR for influenza A or B.

RESULTS

Of 303 eligible children, 233 (77%) were enrolled. In this population, 19 children had culture- and/or PCR-confirmed influenza A infection, prevalence of 8%. The QuickVue Influenza Test had a sensitivity of 74%, specificity of 98%, positive predictive value of 74%, and negative predictive value of 98%.

CONCLUSIONS

Among children hospitalized with fever/respiratory symptoms during the influenza season, negative bedside QuickVue Influenza Tests indicated very low likelihood of influenza infection, whereas positive tests greatly increased the probability of influenza-associated illness.