Epidemiology of RSV and hMPV in Belgium: a 10-year follow-up

Epidemiology and genetic diversity of human respiratory syncytial virus in Belgium between 2011 and 2019

BACKGROUND

Human respiratory syncytial virus (HRSV) is worldwide one of the leading causes of acute respiratory tract infections in young children and the elderly population. Two distinct subtypes of HRSV (A and B) and a multitude of genotypes have been described. The laboratory of Clinical and Epidemiological Virology (KU Leuven/University Hospitals Leuven) has a long-standing history of HRSV surveillance in Belgium.

METHODS

In this study, the seasonal circulation of HRSV in Belgium was monitored during 8 consecutive seasons prior to the SARS-CoV-2 pandemic (2011-2012 until 2018-2019). By use of a multiplex quantitative real time PCR panel, 27,386 respiratory samples were tested for HRSV. Further subtyping and sequencing of the HRSV positive samples was performed by PCR and Sanger sequencing. The prevalence and positivity rate were estimated in 4 distinct age groups and the circulating strains of each subtype were situated in a global context and in reference to the described genotypes in literature.

RESULTS

HRSV circulated in Belgium in a yearly re-occurring pattern during the winter months and both HRSV subtypes co-circulated simultaneously. All HRSV-B strains contained the 60 nt duplication in the HVR2 region of the G gene. Strains of subtype HRSV-A with a 72 nt duplication in the HVR2 region were first observed during the 2011-2012 season and replaced all other circulating strains from 2014 to 2015 onwards.

Factors associated with severe respiratory syncytial virus infection among hospitalized children in Thammasat University Hospital

Background

Respiratory syncytial virus (RSV) is one of the most significant respiratory pathogens that causes acute lower respiratory tract infections (LRTI) early in life. Most children have a history of RSV infection within 24 months of age, and recurrent infections are common throughout life.

Methods

Children under five years of age were identified through a review of medical records with a diagnosis of RSV-LRTI between 2016 and 2020. Severe RSV-LRTI was defined as a prolonged length of stay (> 7 days), admission to the intensive care unit, need for mechanical ventilation, non-invasive positive pressure ventilation, or in-hospital mortality. Factors associated with severe RSV-LRTI were investigated using univariate and multivariate analyses.

Results

During the study period, 620 patients were diagnosed with RSV-LRTI and 249 (40.16%) patients had severe RSV-LRTI. In the multivariable logistic regression analysis, the factors for severe RSV-LRTI were being under 3 months (aOR 2.18 CI 1.39-3.43, p0.001), cardiovascular disease (aOR 3.55 CI 1.56-8.06, p0.002), gastrointestinal disease (aOR 5.91 CI 1.90-18.46, p0.002), genetic disease (aOR 7.33 CI 1.43-37.54, p0.017), and pulmonary disease (aOR 9.50, CI 4.56-19.80, p<0.001). Additionally, the presence of ≥ 2 co-morbidities (aOR 6.23 CI 2.81-14.81, p<0.016), experiencing illness for more than 5 days (aOR 3.33 CI 2.19-5.06, p<0.001), co-detection of influenza (aOR 8.62 CI 1.49-38.21, p0.015), and nosocomial RSV infection (aOR 9.13 CI 1.98-41.30, p0.012), markedly increased the risk of severe RSV-LTRI. The severe RSV-LRTI group demonstrated higher hospitalization expenses (median, US $720.77 vs $278.00, respectively; p<0.001), and three infants died in-hospital.

Conclusion

Children at high risk for RSV-LRTI due to underlying genetic and gastrointestinal diseases are at an increased risk for severe RSV-LRTI. Further studies to determine the cost-effectiveness of RSV immunization in these potential co-morbidities should be initiated to prioritize RSV immunization, especially in resource-constrained regions with limited availability of nirsevimab.

Exploring Clinical Predictors of Severe Human Metapneumovirus Respiratory Tract Infections in Children: Insights from a Recent Outbreak

Human metapneumovirus (hMPV) is an important pathogen that causes both upper (URTIs) and lower respiratory tract infections (LRTIs) in children. The virus can be implicated in severe bronchiolitis and pneumonia, necessitating hospitalization, with certain cases requiring intensive care unit intervention. As part of a retrospective observational study, we aimed to identify indicators of severe hMPV respiratory tract infections in children referred to the University Children's Hospital Ljubljana and the Department of Infectious Diseases Ljubljana, Slovenia, during a recent outbreak. We analyzed clinical data from November 2022 to January 2023 and compared the characteristics of children presenting with URTIs and LRTIs. We also examined the characteristics of children with hMPV LRTIs, distinguishing between children with and without LRTI-associated hypoxemia. Of 78 hMPV-PCR-positive pediatric patients (mean age 3.1 years; 60.3% boys), 36% had a URTI, and 64% had an LRTI. Hospitalization was required in 64% (50/78), with 42% (21/50) requiring oxygen therapy. LRTI-associated hypoxemia was more common in patients with atopy who showed dyspnea, tachypnea, crackles, and wheezing on lung auscultation. In a multivariable logistic regression analysis, wheezing detected on lung auscultation was a significant predictive factor for hypoxemic hMPV-LRTI. Specifically, children presenting with wheezing were found to be ten times more likely to experience hypoxemia. Prematurity and chronic conditions did not influence the presentation or severity of hMPV infection. This study highlights wheezing and atopy as crucial indicators of severe hMPV LRTI in children, emphasizing the importance of early recognition and intervention.

Protective efficacy of a novel recombinant influenza virus carrying partial human metapneumovirus F protein epitopes

Human metapneumovirus (HMPV) is a leading cause of acute respiratory tract infections in infants and children. Currently, no approved HMPV vaccine is available. We developed a novel recombinant influenza virus, which carried partial HMPV F protein (HMPV-F) epitopes, utilizing reverse genetics. The novel single-stranded RNA virus, termed rFLU-HMPV/F-NA, was synthesized in the neuraminidase (NA) fragment of influenza virus A/PuertoRico/8/34 (PR8). The morphological characteristics of rFLU-HMPV/F-NA were consistent with the wild-type flu virus. The virus could passage in specific pathogen-free (SPF) chicken embryos for at least five consecutive generations with haemagglutinin (HA) titres of 28-9 or 8-9LogTCID50/mL. BALB/c mice were intranasally immunized at 21-day intervals with 104 TCID50 (low-dose group) or 106 TCID50 (high-dose group) rFLU-HMPV/F-NA, and PBS or PR8 vaccine was used for the control group. rFLU-HMPV/F-NA induced robust humoral, mucosal, and cellular immune responses in vivo in a dose-dependent manner. More importantly, wt clinical HMPV isolate challenge studies showed that rFLU-HMPV/F-NA provided significant immune protection against HMPV infection compared to the PBS or PR8 vaccine control group, as shown by improved histopathological changes and reduced viral titres in the lungs of immunized mice post-challenge. These findings demonstrate that rFLU-HMPV/F-NA has potential as a promising HMPV candidate vaccine and warrants further investigation into its control of HMPV infection.

Bronchiolitis Due to RSV and HMPV-Epidemiology, Clinical Course, and Prognosis: Experience of a Single Tertiary Center

Acute bronchiolitis is a leading cause of hospitalization in infants. In this retrospective study, 645 patients with acute bronchiolitis diagnosed as respiratory syncytial virus (RSV; n = 538) or human metapneumovirus (HMPV; n = 107) were compared in terms of demographic, clinical, and laboratory findings. The HMPV patients presented later in the winter, were older (20 vs 7.55 months; P < .001)), had higher levels of C-reactive protein (4.55 vs 3.03 mg/dL; P = .007), and a higher prevalence of complications (43.9% vs 32.7%; P = .03). This study highlights the similarities and differences between these 2 common respiratory viral pathogens and shows that HMPV has a slightly more severe disease course than RSV. These findings can help guide approaches to these 2 common viruses that cause bronchiolitis.

High Incidence of Respiratory Syncytial Virus in Children with Community-Acquired Pneumonia from a City in the Brazilian Pre-Amazon Region

INTRODUCTION

Although fewer children have been affected by the severe form of the coronavirus disease 2019 (COVID-19), community-acquired pneumonia (CAP) continues to be the leading global cause of child hospitalizations and deaths.

AIM

This study investigated the incidence of respiratory syncytial virus (RSV) as well its subtypes (RSV A and B), adenovirus (ADV), rhinovirus (HRV), metapneumovirus (HMPV), coronavirus (NL63, OC43, 229E and HKU1), parainfluenza virus subtypes (PI1, PI2 and PI3), bocavirus and influenza A and B viruses (FluA and FluB) in children diagnosed with CAP during the COVID-19 pandemic.

METHODS

A total of 200 children with clinically confirmed CAP were initially recruited, of whom 107 had negative qPCR results for SARS-CoV-2 and were included in this study. Viral subtypes were identified using a real-time polymerase chain reaction in the nasopharyngeal swab samples.

RESULTS

Viruses were identified in 69.2% of the patients. RSV infections were the most frequently identified (65.4%), with type RSV B being the most prevalent (63.5%). In addition, HCoV 229E and HRV were detected in 6.5% and 3.7% of the patients, respectively. RSV type B was associated with severe acute respiratory infection (ARI) and a younger age (less than 24 months).

CONCLUSIONS

New strategies for preventing and treating viral respiratory infections, particularly RSV infections, are necessary.

The emergence, impact, and evolution of human metapneumovirus variants from 2014 to 2021 in Spain

BACKGROUND

Human metapneumovirus (HMPV) is an important aetiologic agent of respiratory tract infection (RTI). This study aimed to describe the prevalence, genetic diversity, and evolutionary dynamics of HMPV.

METHODS

Laboratory-confirmed HMPV were characterised based on partial-coding G gene sequences with MEGA.v6.0. WGS was performed with Illumina, and evolutionary analyses with Datamonkey and Nextstrain.

RESULTS

HMPV prevalence was 2.5%, peaking in February-April and with an alternation in the predominance of HMPV-A and -B until the emergence of SARS-CoV-2, not circulating until summer and autumn-winter 2021, with a higher prevalence and with the almost only circulation of A2c_111dup. G and SH proteins were the most variable, and 70% of F protein was under negative selection. Mutation rate of HMPV genome was 6.95 ×10^-4 substitutions/site/year.

CONCLUSION

HMPV showed a significant morbidity until the emergence of SARS-CoV-2 pandemic in 2020, not circulating again until summer and autumn 2021, with a higher prevalence and with almost the only circulation of A2c_111dup, probably due to a more efficient immune evasion mechanism. The F protein showed a very conserved nature, supporting the need for steric shielding. The tMRCA showed a recent emergence of the A2c variants carrying duplications, supporting the importance of virological surveillance.

Retrospective comparison of respiratory syncytial virus and metapneumovirus clinical presentation in hospitalized children

Respiratory syncytial virus (RSV) and Human metapneumovirus (hMPV), members of Pneumoviridae family are common causes of acute respiratory tract infections (ARTI) among children. Study material includes routine nasopharyngeal samples obtained during 8-year period for hMPV and one single season for RSV in children hospitalized for ARTI between 0 and 15 years at the Center Hospitalier Universitaire (CHU) Saint Pierre in Brussels. Positive samples for RSV or hMPV identified by viral culture, lateral flow chromatography test for RSV or direct fluorescent assay for hMPV were selected retrospectively. Characteristics of children hospitalized for RSV or hMPV infections were compared. Children hospitalized for RSV infection were significantly younger and requiring more respiratory support, longer hospital stay and transfers in Pediatric intensive Care Units than those hospitalized for hMPV infection. Pneumonia diagnostic and antibiotics therapies were more significantly associated with hMPV infections. In conclusion, despite their genetic similarities, RSV, and hMPV present epidemiological and clinical differences in pediatric infections. Our results should be confirmed prospectively.

The burden and surveillance of RSV disease in young children in Belgium-expert opinion

Infections with respiratory syncytial virus (RSV) can cause severe disease. In young children, RSV is the most common cause of lower respiratory tract illness and life-threatening infections most commonly occur in the first years of life. In adults, elderly and immunocompromised people are most vulnerable. Recently there has been an acceleration in the development of candidate RSV vaccines, monoclonal antibodies and therapeutics which are expected to become available in Europe within the next 2-10 years. Understanding the true burden of childhood RSV disease will become very important to support public health authorities and policy makers in the assessment of new therapeutic opportunities against RSV disease. A systematic literature search was performed to map local data on the burden of RSV disease and to evaluate available RSV surveillance systems. A group of 9 paediatric infectious diseases specialists participated in an expert panel. The purpose of this meeting was to evaluate and map the burden associated with RSV infection in children, including patient pathways and the epidemiological patterns of virus circulation in Belgium. Sources of information on the burden of RSV disease in Belgium are very limited. For the outpatient setting, it is estimated that 5-10% of young patients seen in primary care are referred to the hospital. Around 3500 children between 0 and 12 months of age are hospitalized for RSV-bronchiolitis every year and represent the majority of all hospitalizations. The current Belgian RSV surveillance system was evaluated and found to be insufficient. Knowledge gaps are highlighted and future perspectives and priorities offered.

CONCLUSION

The Belgian population-based RSV surveillance should be improved, and a hospital-led reporting system should be put in place to enable the evaluation of the true burden of RSV disease in Belgium and to improve disease management in the future.

WHAT IS KNOWN

• RSV bronchiolitis is a very important cause of infant hospitalization. • The burden of disease in the community is poorly studied and underestimated.

WHAT IS NEW

• This expert opinion summarizes knowledge gaps and offers insights that allow improvement of local surveillance systems in order to establish a future-proof RSV surveillance system.

Burden of severe bronchiolitis in children up to 2 years of age in Spain from 2012 to 2017

Bronchiolitis represents a heavy burden of disease in children under 2 years of age in our society due to the high infectivity of the Respiratory Syncytial Virus [RSV] and the vulnerability of the youngest children.The objective of this retrospective epidemiological study was to show the burden of severe bronchiolitis in Spain through population-based estimates of hospitalizations due to bronchiolitis in children up to 24 months old during a 6-year period (2012-2017).A total of 100,115 cases of bronchiolitis required hospitalization in Spain from 2012 to 2017. Most cases of bronchiolitis that required hospitalization were in infants under 3 months of age. The hospitalization rate for bronchiolitis for children under 1 year of age was 3,838.27 per 100,000 healthy children. During the 6-year study period, a total of 82 deaths due to bronchiolitis were reported among hospitalized infants. Among these deaths, more than 50% were in patients younger than 3 months of age. The annual average cost to the National Health Care System was €58 M, with a mean hospitalization cost of €3,512 per case.

Role of Differences in Respiratory Syncytial Virus F and G Glycoproteins on Susceptibility to Inactivation by Antimicrobial Peptides LL-37 and Human Beta-Defensins

Antimicrobial peptides are proteins that have been found to be an important factor in the natural immune response to a variety of pathogens. Respiratory syncytial virus (RSV) is a respiratory pathogen with the capability to cause serious upper and lower respiratory infections in infants and children and is a major viral cause of infant mortality. There is currently no functional vaccine for the virus, as recent efforts have been hindered by the virus's low immunogenicity, its ability to effectively mutate, and underlying instabilities of potential vaccines. Previous studies have shown that antimicrobial peptides may affect viral replication and spread of RSV. Our study evaluates the susceptibility of chimeric strains of RSV that express different fusion (F) and attachment (G) proteins to susceptibilities to inactivation by LL-37 and human beta-defensins (hBDs) hBD-1, hBD-3, and hBD-4. We show that LL-37 and hBD-3 result in dose-dependent, strain-independent inactivation of RSV, whereas treatment with either hBD-1 or hBD-4 appears more variable between strains. This suggests a potential role of the viral structural proteins in mitigating the inhibitory effects of the peptides. This study provides the first evidence of the sensitivity of RSV to several hBDs and indicates a role of LL-37 and beta-defensins in both limiting establishment of natural RSV infections and in the therapeutic treatment of severe RSV disease.

Risk factors for disease severity and increased medical resource utilization in respiratory syncytial virus (+) hospitalized children: A descriptive study conducted in four Belgian hospitals

Background

We aimed to provide regional data on clinical symptoms, medical resource utilization (MRU), and risk factors for increased MRU in hospitalized respiratory syncytial virus (RSV)-infected Belgian pediatric population.

Methods

This prospective, multicenter study enrolled RSV (+) hospitalized children (aged ≤5y) during the 2013–2015 RSV seasons. RSV was diagnosed within 24h of hospitalization. Disease severity of RSV (+) patients was assessed until discharge or up to maximum six days using a Physical Examination Score (PES) and a derived score based on ability to feed, dyspnea and respiratory effort (PES3). MRU (concomitant medications, length of hospitalization [LOH], and oxygen supplementation) was evaluated. Kaplan-Meier survival analysis was performed to compare MRU by age and presence of risk factors for severe disease. Association between baseline covariates and MRU was analyzed using Cox regression models.

Results

In total, 75 children were included, Median (range) age was 4 (0–41) months, risk factors were present in 18.7%, and early hospitalization (≤3 days of symptom onset) was observed in 57.3% of patients. Cough (100%), feeding problems (82.2%), nasal discharge (87.8%), and rales and rhonchi (82.2%) were frequently observed. Median (range) LOH and oxygen supplementation was 5 (2–7) and 3 (1–7) days. Oxygen supplementation, bronchodilators, and antibiotics were administered to 58.7%, 64.0%, and 41.3% of the patients, respectively. Age <3 months and baseline total PES3 score were associated with probability and the duration of receiving oxygen supplementation. LOH was not associated with any covariate.

Conclusion

RSV is associated with high disease burden and MRU in hospitalized children. Oxygen supplementation but not length of hospitalization was associated with very young age and the PES3 score. These results warrant further assessment of the PES3 score as a predictor for the probability of receiving and length of oxygen supplementation in RSV hospitalized children.

Registration

NCT02133092

The A2c 111nt-dup Variants of Human Metapneumovirus Predominantly Circulating in Qingdao, China, during 2018 and 2019

BACKGROUND

Human metapneumovirus (HMPV) plays an important role in acute respiratory tract infections, especially in children. We investigated the epidemiology of HMPV associated with acute respiratory tract infections (ARTIs) among pediatric inpatients and identified HMPV genetic variations in Qingdao, China, from January 2018 to June 2019.

METHODS

HMPV-positive samples were identified from throat swabs by multiplex real-time RT-PCR. The G gene sequences of HMPV were obtained, followed by phylogenetic analysis.

RESULTS

As a result, 71 out of 1051 (6.76%) patients were HMPV positive, and the HMPV-positive rate in children under 5 years of age was three times higher than that in those aged 5-17 years. The epidemic season of HMPV was in spring, with a peak mainly in March. Thirty-two nucleotide sequences of the HMPV G gene successfully obtained were clustered into 3 genotypes, A2c (25/32, 78.13%), B1 (3/32, 9.38%) and B2 (4/32, 12.50%). In addition, 76% (19/25) of A2c viruses were identified as the emerging A2c_111nt-dup variants, which were predominantly circulating among pediatric inpatients with ARTIs between January 2018 and June 2019 in Qingdao.

CONCLUSIONS

The emerging A2c_111nt-dup variants have spread between countries and cities and might spread more widely in the future. Further prevalence monitoring of this duplication variant is needed to clarify the potentially expanding transmission and to provide a scientific basis for disease control and vaccine development. This article is protected by copyright. All rights reserved.

Burden of respiratory syncytial virus-associated lower respiratory infections in children in Spain from 2012 to 2018

BACKGROUND

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infection (ALRI) leading to infant hospitalization, morbidity and postnatal mortality in children younger than 5 years of age worldwide. The aim of this study was to collect data on hospitalizations for RSV-related ALRI in children in Spain from 2012 to 2018.

METHODS

We used the discharge reports from the Minimum Basic Data Set (MBDS) to retrospectively analyze hospital discharge data in children ≤ 14 years of age with a diagnosis of acute lower respiratory tract infection, based on the ICD-9-CM and ICD-10-CM diagnosis codes, from 2012 to 2018.

RESULTS

A total of 190,474 children, 58.1% boys and 41.9% girls, were admitted for lower respiratory tract infections in Spain, including 118,731 cases of bronchiolitis, 53,972 cases of bronchitis, 3710 cases of RSV-positive pneumonia, and 14,061 cases of RSV infections. Of these, 92,426 children (48.5%) had laboratory-confirmed RSV infection. The mean case fatality rate was almost 6 times higher for pneumonia (0.6%) than for bronchiolitis (0.1%) or bronchitis (0.1%). A significant linear increase in the mean annual hospitalization rate for pneumonia of almost 15% per year was found, with no changes in the trend over the study period.

CONCLUSIONS

RSV-related respiratory infections remain a leading cause of infant hospitalization in Spain. Effective antiviral treatments and preventive vaccines are urgently needed for the management of RSV infection in children, especially for those aged 6 to 12 months.

Comparison of the clinical features of human bocavirus and metapneumovirus lower respiratory tract infections in hospitalized children in Suzhou, China

OBJECTIVE

We compared the clinical data of hospitalized children with lower respiratory tract infections caused by human bocavirus (HBoV) and human metapneumovirus (hMPV).

METHODS

In total, 8,430 children admitted to the Department of Respiration, Children's Hospital of Soochow University for lower respiratory tract infections from January 2017 to October 2021 were enrolled. Seven common respiratory viruses, including respiratory syncytial virus, influenza virus A, influenza virus B, parainfluenza virus (PIV) I, PIV II, PIV III, and adenovirus, were detected by direct immunofluorescence assay, whereas human rhinovirus and hMPV were detected by reverse transcription-polymerase chain reaction. Mycoplasma pneumoniae (MP) and HBoV were detected by real-time fluorescence quantitative polymerase chain reaction. Bacteria was detected in blood, nasopharyngeal secretion, bronchoalveolar lavage specimen or pleural fluid by culture. In parallel, MP was detected by enzyme-linked immunosorbent assay. In addition, we performed metagenomic testing of alveolar lavage fluid from some of the patients in our study.

RESULTS

The detection rate of HBoV was 6.62% (558/8430), whereas that of hMPV was 2.24% (189/ 8430). The detection rate of HBoV was significantly higher in children aged 1 to <3 years than in other age groups, but there were no significant differences in positivity rates for hMPV by age. Before 2020, the incidence of HBoV infection peaked in summer and autumn, whereas that of hMPV peaked in spring. The epidemiology of both HBoV and hMPV has changed because of the impact of the novel coronavirus. Among the positive cases, the HBoV mixed infection rate was 51.6%, which was similar to that for hMPV mixed infection (44.4%). Comparing clinical characteristics between HBoV and hMPV single infection, the median age of children was 17 months in the HBoV group and 11 months in the hMPV group. In the HBoV single infection group, 31 patients (11.5%) had pulse oxygen saturation of less than 92% on admission, 47 (17.4%) had shortness of breath, and 26 (9.6%) presented with dyspnea. Meanwhile, four patients (3.8%) in the hMPV single infection group had pulse oxygen saturation of less than 92% on admission, eight (7.6%) displayed shortness of breath, and three (2.9%) had dyspnea. The proportion of patients requiring mechanical ventilation and the rate of PICU admission were higher in the HBoV group than in the hMPV group.

CONCLUSION

The prevalence of HBoV infection is higher than that of hMPV infection in children with lower respiratory tract infection in Suzhou, and HBoV is more likely to cause severe infection than hMPV. Public health interventions for COVID-19 outbreaks have affected the prevalence of HBoV and hMPV.

The spatial-temporal dynamics of respiratory syncytial virus infections across the east-west coasts of Australia during 2016-17

Respiratory syncytial virus (RSV) is an important human respiratory pathogen. In temperate regions, a distinct seasonality is observed, where peaks of infections typically occur in early winter, often preceding the annual influenza season. Infections are associated with high rates of morbidity and mortality and in some populations exceed that of influenza. Two subtypes, RSV-A and RSV-B, have been described, and molecular epidemiological studies have shown that both viruses mostly co-circulate. This trend also appears to be the case for Australia; however, previous genomic studies have been limited to cases from one Eastern state—New South Wales. As such, the broader spatial patterns and viral traffic networks across the continent are not known. Here, we conducted a whole-genome study of RSV comparing strains across eastern and Western Australia during the period January 2016 to June 2017. In total, 96 new RSV genomes were sequenced, compiled with previously generated data, and examined using a phylodynamic approach. This analysis revealed that both RSV-A and RSV-B strains were circulating, and each subtype was dominated by a single genotype, RSV-A ON1-like and RSV-B BA10-like viruses. Some geographical clustering was evident in strains from both states with multiple distinct sub-lineages observed and relatively low mixing across jurisdictions, suggesting that endemic transmission was likely seeded from imported, unsampled locations. Overall, the RSV phylogenies reflected a complex pattern of interactions across multiple epidemiological scales from fluid virus traffic across global and regional networks to fine-scale local transmission events.

Exploring the epidemiological changes of common respiratory viruses since the COVID-19 pandemic: a hospital study in Hangzhou, China

Adenovirus, respiratory syncytial virus, and influenza virus are common causes of respiratory infections. The COVID-19 pandemic had a significant impact on their prevalence. The aim of this study was to analyze the epidemic changes of common respiratory viruses in the Affiliated Hospital of Hangzhou Normal University in Hangzhou, China, from October of 2017 to February of 2021. We collected statistics from 121,529 patients in the outpatient and inpatient departments of the hospital who had throat or nose swabs collected for testing for four virus antigens by the colloidal gold method. Of these, 13,200 (10.86%) were positive for influenza A virus, 8,402 (6.91%) were positive for influenza B virus, 6,056 (4.98%) were positive for adenovirus, and 4,739 (3.90%) were positive for respiratory syncytial virus. The positivity rates of the influenza A virus (0-14 years old, P = 0.376; over 14 years old, P = 0.197) and respiratory syncytial virus (0-14 years old, P = 0.763; over 14 years old, P = 0.465) did not differ significantly by gender. After January of 2020, influenza virus infection decreased significantly. The positivity rate of respiratory syncytial virus remained high, and its epidemic season was similar to before. Strict respiratory protection and regulation of crowd activities have a great impact on the epidemic characteristics of viruses. After major changes in the public health environment, virus epidemics and their mutations should be monitored closely, extensively, and continuously.

Prevalence and Risk Factors of Respiratory Syncytial Virus in Children under 5 Years of Age in the WHO European Region: A Systematic Review and Meta-Analysis

A respiratory syncytial virus (RSV) is the major cause of respiratory tract infection in children under 5 years. However, RSV infection in the European Region of the World Health Organization has not been systematically reviewed. The aim was to determine the prevalence and factors associated with RSV in children under 5 years of age in European regions. A systematic review and meta-analysis was performed. CINAHL, Medline, LILACS, ProQuest, SciELO, and Scopus databases were consulted for studies published in the last 5 years, following Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. The search equation was "respiratory syncytial virus AND (newborn OR infant OR child) AND (prevalence OR risk factors)". Studies reporting the prevalence of RSV were eligible for inclusion in the meta-analysis. A total of 20 articles were included. The meta-analytic prevalence estimation of RSV, with a sample of n = 16,115 children, was 46% (95% CI 34-59%). The main risk factors were age, male gender, winter season, and environmental factors such as cold temperatures, higher relative humidity, high concentrations of benzene, exposure to tobacco, and living in urban areas. Robust age-specific estimates of RSV infection in healthy children should be promoted in order to determine the optimal age for immunization. In addition, it is necessary to analyse in greater depth the potentially predictive factors of RSV infection, to be included in prevention strategies.

Burden of respiratory syncytial virus infection in community-dwelling older adults in Europe (RESCEU): an international prospective cohort study

BACKGROUND

Respiratory syncytial virus (RSV) infection in older adults is recognised as an important health issue. We aimed to assess the community burden of RSV in Europe in older adults aged ≥60 years.

METHODS

This international, prospective, observational cohort study is part of work by the REspiratory Syncytial virus Consortium in EUrope (RESCEU). Participants were recruited through general practitioners' (GPs) offices before two independent RSV seasons. Participants reported weekly about symptoms of acute respiratory tract infection (ARTI) during one RSV season. ARTI patients were tested for RSV during home visits and completed a daily symptom diary. RSV illness included PCR-confirmed ARTI and those showing seroconversion over the season. RSV ARTI was based on PCR alone (ClinicalTrials.gov, NCT03621930).

RESULTS

We recruited 1040 participants (527 in season 2017-2018 and 513 in season 2018-2019) with a median age of 75 years (range 60-100 years). Of these, 1023 (99%) lived independently at home at baseline. RSV illness incidence was 22 out of 527 (4.2%) and 37 out of 513 (7.2%) in the respective seasons. RSV illness did not affect frailty or cardiopulmonary status during the course of the study. No patients were hospitalised or died from RSV illness. In the 36 patients with PCR confirmed RSV ARTI, symptom duration averaged 19 days, while a doctor's visit took place in 11 out of 36 cases (31%). RSV ARTI could not be differentiated clinically from all other ARTIs based on symptoms.

CONCLUSION

This European study showed that RSV is prevalent in community-dwelling older adults and rarely causes severe disease. This suggests that watchful waiting, using a continuity of care approach to identify those who do need more intensive care, is often justified when RSV is suspected in family practice.

Viral etiology and epidemiology of pediatric patients hospitalized for acute respiratory tract infections in Macao: a retrospective study from 2014 to 2017

Background

Acute respiratory infections (ARIs) are among the leading causes of hospitalization in children. Understanding the local dominant viral etiologies is important to inform infection control practices and clinical management. This study aimed to investigate the viral etiology and epidemiology of respiratory infections among pediatric inpatients in Macao.

Methods

A retrospective study using electronic health records between 2014 and 2017 at Kiang Wu Hospital was performed. Nasopharyngeal swab specimens were obtained from hospitalized children aged 13 years or younger with respiratory tract diseases. xMAP multiplex assays were employed to detect respiratory agents including 10 respiratory viruses. Data were analyzed to describe the frequency and seasonality.

Results

Of the 4880 children enrolled in the study, 3767 (77.1%) were positive for at least one of the 13 viral pathogens tested, of which 2707 (55.5%) being male and 2635 (70.0%) under 2 years old. Among the positive results, there were 3091 (82.0%) single infections and 676 (18.0%) multiple infections. The predominant viruses included human rhinovirus/enterovirus (HRV/EV 27.4%), adenovirus (ADV, 15.8%), respiratory syncytial virus B (RSVB, 7.8%) and respiratory syncytial virus A (RSVA, 7.8%). The detection of viral infection was the most prevalent in autumn (960/1176, 81.6%), followed by spring (1095/1406, 77.9%), winter (768/992, 77.4%), and summer (944/1306, 72.3%), with HRV/EV and ADV being most commonly detected throughout the 4 years of study period. The detection rate of viral infection was highest among ARI patients presented with croup (123/141, 87.2%), followed by lower respiratory tract infection (1924/2356, 81.7%) and upper respiratory tract infection (1720/2383, 72.2%). FluA, FluB and ADV were positive factors for upper respiratory tract infections. On the other hand, infection with RSVA, RSVB, PIV3, PIV4, HMPV, and EV/RHV were positively associated with lower respiratory tract infections; and PIV1, PIV2, and PIV3 were positively associated with croup.

Conclusions

This is the first study in Macao to determine the viral etiology and epidemiology of pediatric patients hospitalized for ARIs. The study findings can contribute to the awareness of pathogen, appropriate preventative measure, accurate diagnosis, and proper clinical management of respiratory viral infections among children in Macao.

Risk factors of severe hospitalized respiratory syncytial virus infection in tertiary care center in Thailand

AIM

To determine factors associated with severe hospitalized Respiratory syncytial virus (RSV)-associated LRTI and to describe management in tertiary care center.

METHODS

Retrospective medical record review was conducted among children under 5 years old hospitalized with RSV-associated LRTI at King Chulalongkorn Memorial Hospital. Severe RSV-associated LRTI was defined as death, mechanical ventilator, or positive pressure ventilation use, prolonged hospitalization >7 days. Factors associated with severe RSV were analyzed using univariate and multivariate logistic regression.

RESULTS

From January 2011 to December 2016, 427 children were hospitalized. Median age was 10 months (IQR 4.2-23.0). One hundred seventy-four (41%) patients had severe RSV (11 deaths, 56 mechanical ventilators, 19 positive pressure ventilation, and 88 prolonged hospitalization). Factors associated with severe RSV were chronic lung disease (aOR 15.16 [4.26-53.91]), cirrhosis/biliary atresia (aOR 15.01 [3.21-70.32]), congenital heart disease (aOR 5.11 [1.97-13.23]), chemotherapy (aOR 4.7 [1.34-16.56]), and pre-term (aOR 2.03 [1.13-3.67]). Oxygen therapy was mainly low flow oxygen delivery. 88% of cases received bronchodilator. Parenteral antibiotics were prescribed in 37.9% of cases.

CONCLUSIONS

Children with co-morbidities have higher risk of severe RSV-associated LRTI. More than two-third of patients received bronchodilator, of which was not recommended by American Academy of Pediatrics. The specific treatment and prevention for RSV are urgently needed.

Engineering of Live Chimeric Vaccines against Human Metapneumovirus

Human metapneumovirus (HMPV) is an important human pathogen that, along with respiratory syncytial virus (RSV), is a major cause of respiratory tract infections in young infants. Development of an effective vaccine against Pneumoviruses has proven to be particularly difficult; despite over 50 years of research in this field, no vaccine against HMPV or RSV is currently available. Recombinant chimeric viruses expressing antigens of other viruses can be generated by reverse genetics and used for simultaneous immunization against more than one pathogen. This approach can result in the development of promising vaccine candidates against HMPV, and several studies have indeed validated viral vectors expressing HMPV antigens. In this review, we summarize current efforts in generating recombinant chimeric vaccines against HMPV, and we discuss their potential optimization based on the correspondence with RSV studies.

Experiments Investigating the Competitive Growth Advantage of Two Different Genotypes of Human Metapneumovirus: Implications for the Alternation of Genotype Prevalence

Human metapneumovirus (hMPV) is an important pathogen that causes upper and lower respiratory tract infections in children worldwide. hMPV has two major genotypes, hMPV-A and hMPV-B. Epidemiological studies have shown that the two hMPV genotypes alternate in predominance worldwide in recent years. Co-circulation of the two genotypes of hMPV was usually observed and there is no study about the interaction between them, such as competitive replication, which maybe the possible mechanisms for alternating prevalence of subtypes. Our present study have used two different genotypes of hMPV (genotype A: NL/1/00; B: NL/1/99) in different proportions in animal model (BALB/c mice) and cell model (Vero-E6) separately. The result showed that the competitive growth does exist in BALB/c mice, genotype B had a strong competitive advantage. However, genotype B did not cause more severe disease than non-predominant (genotype A) or mixed strains in the study, which were evaluated by the body weight, airway hyperresponsiveness and lung pathology of mouse. In cell model, competitive growth and the two genotypes alternately prevalence were observed. In summary, we confirmed that there was a competitive replication between hMPV genotype A and B, and no difference in disease severity caused by the two subtypes. This study shows a new insight to understand the alternation of hMPV genotype prevalence through genotype competition and provide experimental evidence for disease control and vaccine design.

HMPV in Immunocompromised Patients: Frequency and Severity in Pediatric Oncology Patients

Cancer is the first cause of death by disease in childhood globally. The most frequent types of cancers in children and adolescents are leukemias, followed by brain and central nervous system tumors and lymphomas. The recovery rate of cancer in children is around 80% in developed countries and up to 30% in developing countries. Some of the main causes of complications in children and adolescents with cancer are respiratory viral infections, mainly in bone marrow-transplanted patients. Respiratory viruses have been detected in the bronchoalveolar lavage or nasal wash specimens from cancer patients with or without respiratory illness symptoms. Human metapneumovirus (HMPV) is within the ten most common viruses that are encountered in samples from pediatric patients with underlying oncology conditions. In most of cases, HMPV is found as the only viral agent, but co-infection with other viruses or with bacterial agents has also been reported. The discrepancies between the most prevalent viral agents may be due to the different populations studied or the range of viral agents tested. Some of the cases of infection with HMPV in cancer patients have been fatal, especially in those who have received a hematopoietic stem cell transplant. This review seeks to show a general view of the participation of HMPV in respiratory illness as a complication of cancer in childhood and adolescence.