Molecular and clinical characteristics of respiratory syncytial virus infections in hospitalized children

Burden of respiratory syncytial virus (RSV) infection in Germany: a systematic review

BACKGROUND

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory infection and hospitalizations among infants, young children, and the elderly. This systematic literature review aimed to summarize the epidemiological and economic burden estimates of RSV infection at any age in Germany.

METHODS

We conducted a systematic literature search to identify full-text articles published from 2003 to 2023 and reporting data on the epidemiological or economic burden of RSV in Germany. Based on pre-specified eligibility criteria, data on incidence, rates of hospital and intensive care unit (ICU) admission, clinical manifestation, underlying conditions, seasonality, health care resource use and costs were extracted.

RESULTS

After screening 315 full-text articles, we included 42 articles in the review. The characteristics of the included studies were heterogenous regarding study population, setting, age groups and RSV-related outcome measures. The most frequently reported epidemiological outcome measures were RSV detection rate (n = 33), followed by clinical manifestation (n = 19), seasonality (n = 18), and underlying conditions of RSV infection (n = 13). RSV detection rates were reported across heterogenous study populations, ranging from 5.2 to 55.4% in pediatric inpatient cases and from 2.9 to 14% in adult inpatient cases. All articles that reported RSV detection rates across several age groups demonstrated the highest burden in infants and young children. Few articles reported RSV-related outcome measures distinctively for the outpatient setting. Health care resource use, such as hospital length of stay, ICU admission rate and treatment of patients with RSV infection were described in 23 articles, of which only one study quantified associated costs from 1999 to 2003 for children ≤ 3 years. In-hospital ICU admission rates varied between 3.6 and 45%, depending on population characteristics as age and underlying conditions.

CONCLUSIONS

This systematic review revealed that RSV imposes substantial disease burden in infants, young children, and the elderly in Germany, whereby infants are particularly affected. To date, there has been limited exploration of the impact of RSV infection on healthy children or the elderly in Germany. Given their notably high reported burden in studies, the medical and economic RSV burden in these groups should move more into focus.

Burden of respiratory syncytial virus infections in China: Systematic review and meta-analysis

BACKGROUND

Respiratory syncytial virus (RSV) is the most important cause of acute respiratory tract infection (ARTI) related morbidity and mortality worldwide. However, the disease burden due to RSV has not been systematically summarized in China.

METHOD

A systematic search was performed in the Chinese BioMedical Database (CBM), China National Knowledge Infrastructure (CNKI), Wanfang database and PubMed to identify available published RSV studies in China.

RESULTS

A total of 489 641 patients with ARTIs from 135 studies were included in the analysis. Among patients with ARTIs, RSV accounted for 18.7% (95% confidence interval CI 17.1-20.5%). The prevalence of RSV was highest in infants (26.5%, 95% CI 23.7-29.5%) and lowest in those aged ≥16 years (2.8%, 95% CI 1.3-6.1). A higher prevalence of RSV was seen in inpatients (22%, 95% CI 19.9-24.2%) than in outpatients (14%, 95% CI 9.6-19.9%). RSV type A accounted for 63.1% (95% CI 52.3-72.8%) of all RSV infections. RSV infections occurred mainly in winter and spring. The most common clinical manifestations were cough, production of sputum, wheezing and fever.

CONCLUSION

RSV is the leading cause of viral ARTIs in China, particularly in infants and young children. Our findings are valuable for guiding the selection of appropriate therapies for ARTIs and implementation of preventive measures against RSV infections. Our data further supports the development of a successful RSV vaccine as a high priority.

Epidemic activity of respiratory syncytial virus is related to temperature and rainfall in equatorial tropical countries

Although viral acute lower respiratory infections (ALRIs) are a major public health problem in tropical low- and middle-income countries (LMICs), and there is growing evidence showing their relationship with meteorological parameters, studies performed in these countries are scarce. In an analytical cross-sectional study, we determined which of the main meteorological parameters (temperature, absolute humidity, rainfall, wind speed, and solar radiation) predicted respiratory syncytial virus (RSV) activity in a population of hospitalized children with ALRI during a 5-year period, from January 2009 to December 2013. Out of a total of 4559 children included in the study (mean age 9·2 ± 8·5 months), 2953 (64·8%) presented RSV infection during the 3-month period from March to May. In the multivariate analysis, after controlling for absolute humidity, wind speed, and solar radiation, temperature [incidence rate ratio (IRR) 2·25, 95% confidence interval (CI) 1·11-4·53, P = 0·024], and rainfall (IRR 1·01, 95% CI 1·00-1·02, P = 0·044) were independently associated with the monthly number of RSV infections. In conclusion, in Bogota, the capital of a tropical LMIC lying slightly above the equator, RSV activity peaks in the 3-month period from March to May, the main rainy period of the year in the city. In addition, rainfall and temperature are the two most important meteorological parameters that are independently associated with RSV activity in hospitalized children with ALRI in the city.

Influenza viruses in Thailand: 7 years of sentinel surveillance data, 2004-2010

Please cite this paper as: Chittaganpitch et al. (2012) Influenza viruses in Thailand: 7 years of sentinel surveillance data, 2004–2010. Influenza and Other Respiratory Viruses 6(4), 276–283.

Background  The re‐emergence of avian influenza A (H5N1) in 2004 and the pandemic of influenza A (H1N1) in 2009 highlight the need for routine surveillance systems to monitor influenza viruses, particularly in Southeast Asia where H5N1 is endemic in poultry. In 2004, the Thai National Institute of Health, in collaboration with the US Centers for Disease Control and Prevention, established influenza sentinel surveillance throughout Thailand.

Objectives  To review routine epidemiologic and virologic surveillance for influenza viruses for public health action.

Methods  Throat swabs from persons with influenza‐like illness and severe acute respiratory illness were collected at 11 sentinel sites during 2004–2010. Influenza viruses were identified using the standard protocol for polymerase chain reaction. Viruses were cultured and identified by immunofluorescence assay; strains were identified by hemagglutination inhibition assay. Data were analyzed to describe frequency, seasonality, and distribution of circulating strains.

Results  Of the 19 457 throat swabs, 3967 (20%) were positive for influenza viruses: 2663 (67%) were influenza A and able to be subtyped [21% H1N1, 25% H3N2, 21% pandemic (pdm) H1N1] and 1304 (33%) were influenza B. During 2009–2010, the surveillance system detected three waves of pdm H1N1. Influenza annually presents two peaks, a major peak during the rainy season (June–August) and a minor peak in winter (October–February).

Conclusions  These data suggest that March–April may be the most appropriate months for seasonal influenza vaccination in Thailand. This system provides a robust profile of the epidemiology of influenza viruses in Thailand and has proven useful for public health planning.

Respiratory viruses in children admitted to hospital intensive care units: evaluating the CLART® Pneumovir DNA array

Viruses play a significant part in children's respiratory infections, sometimes leading to hospitalization in cases of severe respiratory distress. The aim of this study was to investigate respiratory infections in children treated in a hospital intensive care unit (ICU). Assays were performed using the CLART® Pneumovir DNA array assay (Genomica, Coslada, Madrid, Spain), which makes it possible to detect 11 genus of respiratory viruses simultaneously. During the winter of 2008–2009, 73 respiratory specimens collected from 53 children under 2 years of age and admitted to an ICU were tested. At least one virus was detected in 78% (57/73) of the samples. The virological diagnosis was based on single infections in 65% (37/57) and on multiple infections in 35% (20/57) of cases. The array assay revealed respiratory syncytial virus (RSV) in 73.6% (42/57) of the samples and rhinovirus in 24.6% (14/57), either on their own or in co‐infections. All viruses identified in single and multiple infections were tested, taking into account clinical features, risk factors, and severity criteria. Children with no risk factors presented more multiple infections, up to 42% of cases, than children with at least one risk factor. RSV seemed to induce severe symptoms by itself as no difference in intubation needs was observed when RSV was detected on its own or in co‐infection. The CLART® Pneumovir DNA array was useful for examining severe viral respiratory infections, when other viruses than those detected by conventional methods could be involved, particularly in an ICU. J. Med. Virol. 83:150–155, 2011. © 2010 Wiley‐Liss, Inc.

Molecular and demographic analysis of respiratory syncytial virus infection in patients admitted to King Chulalongkorn Memorial Hospital, Thailand, 2007

Please cite this paper as: Boonyasuppayakorn et al. (2010) Molecular and demographic analysis of respiratory syncytial virus infection in King Chulalongkorn Memorial Hospital admitted patients, Thailand, 2007. Influenza and Other Respiratory Viruses 4(5), 313–323.

Objectives:  To preliminary preview the molecular character and its possible clinical correlation of RSV subgroups in Thailand.

Design:  Cross‐sectional analytic design.

Setting:  Admitted acute lower respiratory tract infection patients of King Chulalongkorn Memorial Hospital, Bangkok, during Jun–Dec, 2007 were recruited.

Sample:  Nasopharyngeal aspirations were collected.

Main outcome measures:  All samples were analyzed for the presence of RSV glycoprotein G gene by reverse transcription PCR. Molecular character of each subgroup was determined by sequencing. Admission records were also analyzed for clinical correlations.

Results:  Equal infectivity and severity of both RSV subgroups to the patients was shown. Mixed infection was shown to be as common as each single infection, higher than previously reported. GA2 of subgroup A and BA‐IV of subgroup B were the most widespread genotypes and showed their monophyletic origins. From admission records, either type of infection did not show significantly preference in demographic record or clinical severity. Comorbidity, however, was statistically significant that more congenital heart disease was found in negative RSV cases, while more chronic pulmonary disease was in positive cases. Nevertheless, the clinical severity was insignificantly different suggesting that only patients with chronic pulmonary underlying were prone to be infected with RSV.

Conclusions:  This preliminary RSV study showed prevalence of subgroups, types of infection, and common genotypes in an epidemic, uncorrelated to demography or clinical severity.

Human respiratory syncytial virus in children with acute respiratory tract infections in China

There are limited data on the prevalence and clinical and molecular characterization of human respiratory syncytial virus (HRSV) in children with acute respiratory tract infections (ARTIs) in China. From December 2006 to March 2009, 894 nasopharyngeal aspirates (NPAs) were collected from children under 14 years of age with ARTIs. Samples were screened for HRSV and genotyped by reverse transcription-PCR (RT-PCR) and sequencing. Demographic and clinical information was recorded. A total of 38.14% (341/894) of samples were positive for HRSV. Phylogenetic analysis revealed that 60.4% of the selected 227 RSV strains were GA2, 34.4% were BA, 4.8% were GB2, and 0.4% were GB3. A total of 40.47% of all of the RSV-positive samples were coinfected with other respiratory viruses, and adenovirus was the most common additional respiratory virus. No statistical differences were found in the frequency of diagnosis and symptoms between the coinfection group and monoinfection group. Additionally, no statistical differences were found in epidemiological characterizations or disease severity between genotype BA- and GA2-positive patients, except for a greater frequency of lower respiratory tract infections (LRTIs) (mostly bronchitis)with BA. HRSV is the most important viral pathogen in Chinese children with ARTIs. Four genotypes (i.e., GA2, BA, GB2, and GB3) circulate locally, and the predominant genotype may shift between seasons. Coinfection with other viruses does not affect disease severity. HRSV genotypes were not associated with different epidemiological characterizations or disease severity.

Mixed respiratory virus infections

Mixed respiratory viral infections are double negative common and evidence that they are associated with severe disease is supported by some groups. This controversial observation can be explained by the lack of sensitivity of the assessed methods used for viral identification and by the small number of patients included in the randomized cohorts studied. Most studies showed that respiratory syncytial virus (RSV) is identified in about 70% of hospitalized infants with bronchiolitis during seasonal winter epidemics, followed by human metapneumovirus (hMPV, about 3-19%) or rhinoviruses (about 20%). Other respiratory viruses have also been reported, indicating significant causes of bronchiolitis and hospitalization during seasonal epidemics. The presence of more than one pathogen, and moreover, the association of RSV with rhinoviruses and also RSV with hMPV, may influence the natural course of bronchiolitis. A better understanding of these various interactions would help future decision-making, such as the extent to which searches for co-pathogens should be conducted in severe bronchiolitis patients already infected by RSV.

The impact of dual viral infection in infants admitted to a pediatric intensive care unit associated with severe bronchiolitis

INTRODUCTION

Bronchiolitis is a major cause of morbidity and mortality in early childhood worldwide. The presence of more than one pathogen may influence the natural history of acute bronchiolitis in infants.

OBJECTIVE

To investigate the relevance of dual viral infection in infants with severe bronchiolitis hospitalized in a short-term unit compared with those in a pediatric intensive care unit (PICU).

STUDY DESIGN

One hundred eighty infants <1 year old hospitalized with bronchiolitis in a short-term unit (n = 92) or admitted to the PICU (n = 88) during 2 consecutive winter seasons 2003/2004 and 2004/2005 were evaluated. Molecular biology and standard methods were used to diagnose human respiratory viruses in nasal/throat swabs and nasal aspirates. Clinical data related to host factors and viral prevalence were compared among infants requiring or not PICU support.

RESULTS

A viral agent was identified in 96.1% of infants with bronchiolitis. Respiratory syncytial virus (70.6% and 73.6%, respectively in the short-term unit and PICU) and rhinovirus (18.5% and 25.3%, respectively in the short-term unit and PICU) were the main detected respiratory viruses in infants hospitalized in both units. No significant difference in viral prevalence was observed between the populations studied. From multivariate analysis, infants with coinfections were 2.7 times (95% CI: 1.2-6.2) more at risk for PICU admission than those with a single infection. Respiratory syncytial virus and rhinovirus were the viruses most frequently identified in mixed infections in infants hospitalized with bronchiolitis.

CONCLUSIONS

Dual viral infection is a relevant risk factor for the admission of infants with severe bronchiolitis to the PICU.