Development and Validation of a New Clinical Scale for Infants with Acute Respiratory Infection: The ReSVinet Scale

Targeted metagenomics reveals association between severity and pathogen co-detection in infants with respiratory syncytial virus

Respiratory syncytial virus (RSV) is the leading cause of hospitalisation for respiratory infection in young children. RSV disease severity is known to be age-dependent and highest in young infants, but other correlates of severity, particularly the presence of additional respiratory pathogens, are less well understood. In this study, nasopharyngeal swabs were collected from two cohorts of RSV-positive infants <12 months in Spain, the UK, and the Netherlands during 2017-20. We show, using targeted metagenomic sequencing of >100 pathogens, including all common respiratory viruses and bacteria, from samples collected from 433 infants, that burden of additional viruses is common (111/433, 26%) but only modestly correlates with RSV disease severity. In contrast, there is strong evidence in both cohorts and across age groups that presence of Haemophilus bacteria (194/433, 45%) is associated with higher severity, including much higher rates of hospitalisation (odds ratio 4.25, 95% CI 2.03-9.31). There is no evidence for association between higher severity and other detected bacteria, and no difference in severity between RSV genotypes. Our findings reveal the genomic diversity of additional pathogens during RSV infection in infants, and provide an evidence base for future causal investigations of the impact of co-infection on RSV disease severity.

A Genome-Wide Association Study of Respiratory Syncytial Virus Infection Severity in Infants

BACKGROUND

Respiratory syncytial virus (RSV) is a significant cause of infant morbidity and mortality worldwide. Most children experience at least one 1 RSV infection by the age of two 2 years, but not all develop severe disease. However, the understanding of genetic risk factors for severe RSV is incomplete. Consequently, we conducted a genome-wide association study of RSV severity.

METHODS

Disease severity was assessed by the ReSVinet scale, in a cohort of 251 infants aged 1 week to 1 year. Genotyping data were collected from multiple European study sites as part of the RESCEU Consortium. Linear regression models were used to assess the impact of genotype on RSV severity and gene expression as measured by microarray.

RESULTS

While no SNPs reached the genome-wide statistical significance threshold (P < 5 × 10-8), we identified 816 candidate SNPs with a P-value of <1 × 10-4. Functional annotation of candidate SNPs highlighted genes relevant to neutrophil trafficking and cytoskeletal functions, including LSP1 and RAB27A. Moreover, SNPs within the RAB27A locus significantly altered gene expression (false discovery rate, FDR P < .05).

CONCLUSIONS

These findings may provide insights into genetic mechanisms driving severe RSV infection, offering biologically relevant information for future investigations.

Substantial Burden of Nonmedically Attended RSV Infection in Healthy-Term Infants: An International Prospective Birth Cohort Study

BACKGROUND

During the first year of life, 1 in 4 infants develops a symptomatic respiratory syncytial virus (RSV) infection, yet only half seek medical attention. The current focus on medically attended RSV therefore underrepresents the true societal burden of RSV. We assessed the burden of nonmedically attended RSV infections and compared with medically attended RSV.

METHODS

We performed active RSV surveillance until the age of 1 year in a cohort (n = 993) nested within the Respiratory Syncytial Virus Consortium in EUrope (RESCEU) prospective birth cohort study enrolling healthy term-born infants in 5 European countries. Symptoms, medication use, wheezing, and impact on family life were analyzed.

RESULTS

For 97 of 120 (80.1%) nonmedically attended RSV episodes, sufficient data were available for analysis. In 50.5% (49/97), symptoms lasted ≥15 days. Parents reported impairment in usual daily activities in 59.8% (58/97) of episodes; worries, 75.3% (73/97); anxiety, 34.0% (33/97); and work absenteeism, 10.8% (10/93). Compared with medically attended RSV (n = 102, 9 hospital admissions), Respiratory Syncytial Virus NETwork (ReSViNET) severity scores were lower (3.5 vs 4.6, P < .001), whereas duration of respiratory symptoms and was comparable.

CONCLUSIONS

Even when medical attendance is not required, RSV infection poses a substantial burden to infants, families, and society. These findings are important for policy makers when considering the implementation of RSV immunization. Clinical Trials Registration. ClinicalTrials.gov (NCT03627572).

External Validation of the Discriminative Validity of the ReSVinet Score and Development of Simplified ReSVinet Scores in Secondary Care

BACKGROUND

There is no consensus on how to best quantify disease severity in infants with respiratory syncytial virus (RSV) and/or bronchiolitis; this lack of a sufficiently validated score complicates the provision of clinical care and, the evaluation of trials of therapeutics and vaccines. The ReSVinet score appears to be one of the most promising; however, it is too time consuming to be incorporated into routine clinical care. We aimed to develop and externally validate simplified versions of this score.

METHODS

Data from a multinational (the Netherlands, Spain, and United Kingdom) multicenter case-control study of infants with RSV were used to develop simplified versions of the ReSVinet score by conducting a grid search to determine the best combination of equally weighted parameters to maximize for the discriminative ability (measured by area under the receiver operating characteristic curve [AUROC]) across a range of outcomes (hospitalization, intensive care unit admission, ventilation requirement). Subsequently discriminative validity of the score for a range of secondary care outcomes was externally validated by secondary analysis of datasets from Rwanda and Colombia.

RESULTS

Three candidate simplified scores were identified using the development dataset; they were excellent (AUROC >0.9) at discriminating for a range of outcomes, and their performance was not significantly different from the original ReSVinet score despite having fewer parameters. In the external validation datasets, the simplified scores were moderate to excellent (AUROC, 0.7-1) across a range of outcomes. In all outcomes, except in a single dataset for predicting admission to the high-dependency unit, they performed at least as well as the original ReSVinet score.

CONCLUSIONS

The candidate simplified scores developed require further external validation in larger datasets, ideally from resource-limited settings before any recommendation regarding their use.

Are lung ultrasound features more severe in infants with bronchiolitis and coinfections?

Background

The lung ultrasound (LUS) score can be a useful tool to predict the need for respiratory support and the length of hospital stay in infants with bronchiolitis.

Objective

To compare lung ultrasound features in neonates and infants up to three months of age with bronchiolitis to determine whether LUS scores (range 0-36) differ in infants with coinfections or not.

Methods

Neonates and infants younger than three months admitted to neonatal units from October 2022 to March 2023, who underwent lung ultrasound evaluation on admission, were included in this retrospective study.

Results

We included 60 patients who underwent LUS evaluation at admission. Forty-two infants (70.0%) had a single viral infection. Eighteen infants (30.0%) had a coinfection: fifteen infants (25.0%) had more than one virus at PCR; one infant (1.7%) had both a viral coinfection and a viral-bacteria coinfection; two infants (3.3%) had viral-bacteria coinfection. Infants with a single viral infection and those with coinfections had similar LUS scores globally and in different lung zones. An LUS score higher than 8 was identified to significantly predict the need for any respiratory support (p = 0.0035), whereas an LUS score higher than 13 was identified to significantly predict the need for mechanical ventilation (p = 0.024).

Conclusion

In our small cohort of neonates and infants younger than three months hospitalized with bronchiolitis, we found no statistically significant differences in the LUS score on admission between patients with a single viral infection and those with multiple infections.

Single-cell immune profiling reveals markers of emergency myelopoiesis that distinguish severe from mild respiratory syncytial virus disease in infants

Whereas most infants infected with respiratory syncytial virus (RSV) show no or only mild symptoms, an estimated 3 million children under five are hospitalized annually due to RSV disease. This study aimed to investigate biological mechanisms and associated biomarkers underlying RSV disease heterogeneity in young infants, enabling the potential to objectively categorize RSV-infected infants according to their medical needs. Immunophenotypic and functional profiling demonstrated the emergence of immature and progenitor-like neutrophils, proliferative monocytes (HLA-DRLow , Ki67+), impaired antigen-presenting function, downregulation of T cell response and low abundance of HLA-DRLow B cells in severe RSV disease. HLA-DRLow monocytes were found as a hallmark of RSV-infected infants requiring hospitalization. Complementary transcriptomics identified genes associated with disease severity and pointed to the emergency myelopoiesis response. These results shed new light on mechanisms underlying the pathogenesis and development of severe RSV disease and identified potential new candidate biomarkers for patient stratification.

Risk Factors Associated with Severe RSV Infection in Infants: What Is the Role of Viral Co-Infections?

The respiratory syncytial virus (RSV) represents the leading cause of viral lower respiratory tract infections (LRTI) in children worldwide and is associated with significant morbidity and mortality rates. The clinical picture of an RSV infection differs substantially between patients, and the role of viral co-infections is poorly investigated. During two consecutive winter seasons from October 2018 until February 2020, we prospectively included children up to 2 years old presenting with an acute LRTI, both ambulatory and hospitalized. We collected clinical data and tested nasopharyngeal secretions for a panel of 16 different respiratory viruses with multiplex RT-qPCR. Disease severity was assessed with traditional clinical parameters and scoring systems. A total of 120 patients were included, of which 91.7% were RSV positive; 42.5% of RSV-positive patients had a co-infection with at least one other respiratory virus. We found that patients suffering from a single RSV infection had higher pediatric intensive care unit (PICU) admission rates (OR = 5.9, 95% CI = 1.53 to 22.74), longer duration of hospitalization (IRR = 1.25, 95% CI = 1.03 to 1.52), and a higher Bronchiolitis Risk of Admission Score (BRAS) (IRR = 1.31, 95% CI = 1.02 to 1.70) compared to patients with RSV co-infections. No significant difference was found in saturation on admission, O2 need, or ReSViNET-score. In our cohort, patients with a single RSV infection had increased disease severity compared to patients with RSV co-infections. This suggests that the presence of viral co-infections might influence the course of RSV bronchiolitis, but heterogeneity and small sample size in our study prevents us from drawing strong conclusions. IMPORTANCE RSV is worldwide the leading cause of serious airway infections. Up to 90% of children will be infected by the age of 2. RSV symptoms are mostly mild and typically mimic a common cold in older children and adolescents, but younger children can develop severe lower respiratory tract disease, and currently it is unclear why certain children develop severe disease while others do not. In this study, we found that children with a single RSV infection had a higher disease severity compared to patients with viral co-infections, suggesting that the presence of a viral co-infection could influence the course of an RSV bronchiolitis. As preventive and therapeutic options for RSV-associated disease are currently limited, this finding could potentially guide physicians to decide which patients might benefit from current or future treatment options early in the course of disease, and therefore, warrants further investigation.

Maternal-Neonatal Outcomes of Obstetric Deliveries Performed in Negative Pressure Isolation Rooms during the COVID-19 Omicron Variant Pandemic in Taiwan: A Retrospective Cohort Study of a Single Institution

Objective: To investigate the maternal−neonatal outcomes of obstetric deliveries performed in negative pressure isolated delivery rooms (NPIDRs) during the coronavirus disease 2019 (COVID-19) omicron variant pandemic period in a single tertiary center in northern Taiwan. Methods: Confirmed positive and suspected-positive COVID-19 cases delivered in NPIDRs and COVID-19-negative mothers delivered in conventional delivery rooms (CDRs) in the period of 1 May 2022 to 31 May 2022 during the COVID-19 omicron variant pandemic stage were reviewed. The maternal−neonatal outcomes between the two groups of mothers were analyzed. All deliveries were performed following the obstetric and neonatologic protocols conforming to the epidemic prevention regulations promulgated by the Taiwan Centers for Disease Control (T-CDC). Multiple gestations, deliveries at gestational age below 34 weeks, and major fetal anomalies were excluded from this study. Results: A total of 213 obstetric deliveries were included. Forty-five deliveries were performed in NPIDRs due to a positive COVID-19 polymerase chain reaction (PCR) test (n = 41) or suspected COVID-19 positive status (n = 4). One hundred and sixty-eight deliveries with negative COVID-19 PCR tests were performed in CDRs. There was no statistical difference in maternal characteristics between the two groups of pregnant women. All COVID-19-confirmed cases either presented with mild upper-airway symptoms (78%) or were asymptomatic (22%); none of these cases developed severe acute respiratory syndrome. The total rate of cesarean section was not statistically different between obstetric deliveries in NPIDRs and in CDRs (38.1% vs. 40.0%, p = 0.82, respectively). Regardless of delivery modes, poorer short-term perinatal outcomes were observed in obstetric deliveries in NPIDRs: there were significant higher rates of neonatal respiratory distress (37.8% vs. 10.7%, p < 0.001, respectively), meconium-stained amniotic fluid (22.2% vs. 4.2%, p < 0.001, respectively) and newborn intensive care unit admission (55.6% vs. 8.3%, p < 0.001, respectively) in obstetric deliveries performed in NPIDRs than in CDRs. Maternal surgical outcomes were not significantly different between the two groups of patients. There was no vertical transmission or nosocomial infection observed in COVID-19 confirmed cases in this study period. Conclusions: Our study demonstrates that obstetric deliveries for positive and suspected COVID-19 omicron-variant cases performed in NPIDRs are associated with poorer short-term perinatal outcomes. Reasonable use of personal protective equipment in NPIDRs could effectively prevent nosocomial infection during obstetric deliveries for pregnant women infected with the COVID-19 omicron variant.

Measuring respiratory syncytial virus infection severity in hospitalized children using the Pediatric Respiratory Syncytial Virus Electronic Severity and Outcome Rating System (PRESORS)

BACKGROUND

The Pediatric Respiratory Syncytial Virus Electronic Severity and Outcome Rating System (PRESORS) was developed to assess the severity of respiratory syncytial virus (RSV) infection in children. Because young children cannot report how they feel or function, ratings are based on observations by the child's caregiver (Observer-Reported Outcome questionnaire [ObsRO]) and clinician (Clinician-Reported Outcome questionnaire [ClinRO]). This prospective study aimed to evaluate the psychometric properties of the PRESORS.

METHODS

The PRESORS version 6 ObsRO and ClinRO were evaluated in children with RSV infection requiring hospitalization in centers in the United States, Argentina, and Chile. Assessments were performed from days 1 to 7 by the child's caregiver and clinician. To assess inter-rater reliability, two clinicians independently performed the ClinRO near in time.

RESULTS

A total of 124 children aged ≤36 months were enrolled (mean age, 8 months). Factor analysis demonstrated that RSV severity consists of two dimensions, respiratory signs and illness behavior, and that these dimensions were consistent over time. The inter-rater reliability for the ClinRO was 0.66 (95% confidence interval [CI], 0.55-0.75) but improved to 0.79 (95% CI, 0.71-0.86) after removing one outlying site, suggesting that quantifying RSV severity is not trivial, even using qualified raters, but that an adequate inter-rater reliability is achievable with the PRESORS through adequate training. ClinRO and ObsRO displayed acceptable internal consistency and acceptable convergent validity with the Respiratory Syncytial Virus Network Scale, global impression scores, and key hospital characteristics.

CONCLUSIONS

The PRESORS is relevant and appropriate for assessing the severity of RSV infection in infants requiring hospitalization.

Clinical and Viral Factors Associated With Disease Severity and Subsequent Wheezing in Infants With Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in infants and young children worldwide. Here we evaluated host demographic and viral factors associated with RSV disease severity in 325 RSV-infected infants under 1 year of age from 3 European countries during 2017-2020. Younger infants had a higher clinical severity (ReSViNET) score and were more likely to require hospitalization, intensive care, respiratory support, and/or mechanical ventilation than older infants (<3 months vs 3 to <6 months and 3 to <6 months vs ≥6 months). Older age (≥6 months vs <3 months), higher viral load, and RSV-A were associated with a greater probability of fever. RSV-A and RSV-B caused similar disease severity and had similar viral dynamics. Infants with a more severe RSV infection, demonstrated by having a higher ReSViNET score, fever, and requiring hospitalization and intensive care, were more likely to have developed subsequent wheezing at 1 year of age.

CLINICAL TRIALS REGISTRATION

NCT03756766.

Clinical pneumonia in the hospitalised child in Malawi in the post-pneumococcal conjugate vaccine era: a prospective hospital-based observational study

OBJECTIVE

Assess characteristics of clinical pneumonia after introduction of pneumococcal conjugate vaccine (PCV), by HIV exposure status, in children hospitalised in a governmental hospital in Malawi.

METHODS AND FINDINGS

We evaluated 1139 children ≤5 years old hospitalised with clinical pneumonia: 101 HIV-exposed, uninfected (HEU) and 1038 HIV-unexposed, uninfected (HUU). Median age was 11 months (IQR 6-20), 59% were male, median mid-upper arm circumference (MUAC) was 14 cm (IQR 13-15) and mean weight-for-height z score was -0.7 (±2.5). The highest Respiratory Index of Severity in Children (RISC) scores were allocated to 10.4% of the overall cohort. Only 45.7% had fever, and 37.2% had at least one danger sign at presentation. The most common clinical features were crackles (54.7%), nasal flaring (53.5%) and lower chest wall indrawing (53.2%). Compared with HUU, HEU children were significantly younger (9 months vs 11 months), with lower mean birth weight (2.8 kg vs 3.0 kg) and MUAC (13.6 cm vs 14.0 cm), had higher prevalence of vomiting (32.7% vs 22.0%), tachypnoea (68.4% vs 49.8%) and highest RISC scores (20.0% vs 9.4%). Five children died (0.4%). However, clinical outcomes were similar for both groups.

CONCLUSIONS

In this post-PCV setting where prevalence of HIV and malnutrition is high, children hospitalised fulfilling the WHO Integrated Management of Childhood Illness criteria for clinical pneumonia present with heterogeneous features. These vary by HIV exposure status but this does not influence either the frequency of danger signs or mortality. The poor performance of available severity scores in this population and the absence of more specific diagnostics hinder appropriate antimicrobial stewardship and the rational application of other interventions.

Wisconsin Upper Respiratory Symptom Survey for Kids: Validation of an Illness-specific Quality of Life Instrument

BACKGROUND

Acute respiratory infections (ARIs) are the most common illness seen in the pediatric ambulatory setting. Research in this area is hampered by the lack of validated ARI measures. The aim of this study was to assess the reliability and validity of the Wisconsin Upper Respiratory Symptom Survey for Kids (WURSS-K), a 15-item instrument, which measures illness-specific symptoms and impact on quality of life during an ARI.

METHODS

WURSS-K was administered to two populations: (1) children aged 4-10 years recruited from the local community and (2) 9- and 10-year-old children from an ongoing study, the Urban Environment and Childhood Asthma.

RESULTS

Overall, 163 children with 249 ARI episodes completed WURSS-K. WURSS-K was analyzed using multiple models to evaluate reliability and validity for a two-factor structure (symptom and functionality) and a single global structure. These models provided evidence of reliability and validity with omega of 0.72 and 0.91 for symptoms and functionality along with the single structure with omega of 0.90.

CONCLUSIONS

WURSS-K shows strong psychometric properties for validity and reliability as either a single global factor or a two-factor structure. This instrument will be useful in both therapeutic trials and observational studies among children with ARI in ambulatory settings.

IMPACT

WURSS-K is a valid and reliable illness-specific quality of life instrument that evaluates the impacts of ARIs on children. WURSS-K is designed for children 4-10 years of age, for whom there is a lack of validated assessment tools. This now validated instrument will be useful for future observational studies and therapeutic trials among children with ARIs in ambulatory settings.

Field testing two existing, standardized respiratory severity scores (LIBSS and ReSViNET) in infants presenting with acute respiratory illness to tertiary hospitals in Rwanda - a validation and inter-rater reliability study

INTRODUCTION

There is a substantial burden of respiratory disease in infants in the sub-Saharan Africa region. Many health care providers (HCPs) that initially receive infants with respiratory distress may not be adequately skilled to differentiate between mild, moderate and severe respiratory symptoms, which may contribute to poor management and outcome. Therefore, respiratory severity scores have the potential to contributing to address this gap.

OBJECTIVES

to field-test the use of two existing standardized bronchiolitis severity scores (LIBSS and ReSViNET) in a population of Rwandan infants (1-12 months) presenting with respiratory illnesses to urban, tertiary, pediatric hospitals and to assess the severity of respiratory distress in these infants and the treatments used.

METHODS

A cross-sectional, validation study, was conducted in four tertiary hospitals in Rwanda. Infants presenting with difficulty in breathing were included. The LIBSS and ReSViNET scores were independently employed by nurses and residents to assess the severity of disease in each infant.

RESULTS

100 infants were recruited with a mean age of seven months. Infants presented with pneumonia (n = 51), bronchiolitis (n = 36) and other infectious respiratory illnesses (n = 13). Thirty-three infants had severe disease and survival was 94% using nurse applied LIBSS. Regarding inter-rater reliability, the intra-class correlation coefficient (ICC) for LIBSS and ReSViNET between nurses and residents was 0.985 (95% CI: 0.98-0.99) and 0.980 (0.97-0.99). The convergent validity (Pearson's correlation) between LIBSS and ReSViNET for nurses and residents was R = 0.836 (p<0.001) and R = 0.815 (p<0.001). The area under the Receiver Operator Curve (aROC) for admission to PICU or HDU was 0.956 (CI: 0.92-0.99, p<0.001) and 0.880 (CI: 0.80-0.96, p<0.001) for nurse completed LIBSS and ReSViNET respectively.

CONCLUSION

LIBSS and ReSViNET were designed for infants with bronchiolitis in resource-rich settings. Both LIBSS and ReSViNET demonstrated good reliability and validity results, in this cohort of patients presenting to tertiary level hospitals. This early data demonstrate that these two scores have the potential to be used in conjunction with clinical reasoning to identify infants at increased risk of clinical deterioration and allow timely admission, treatment escalation and therefore support resource allocation in Rwanda.

Distinct patterns of within-host virus populations between two subgroups of human respiratory syncytial virus

Human respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infection in young children globally, but little is known about within-host RSV diversity. Here, we characterised within-host RSV populations using deep-sequencing data from 319 nasopharyngeal swabs collected during 2017-2020. RSV-B had lower consensus diversity than RSV-A at the population level, while exhibiting greater within-host diversity. Two RSV-B consensus sequences had an amino acid alteration (K68N) in the fusion (F) protein, which has been associated with reduced susceptibility to nirsevimab (MEDI8897), a novel RSV monoclonal antibody under development. In addition, several minor variants were identified in the antigenic sites of the F protein, one of which may confer resistance to palivizumab, the only licensed RSV monoclonal antibody. The differences in within-host virus populations emphasise the importance of monitoring for vaccine efficacy and may help to explain the different prevalences of monoclonal antibody-escape mutants between the two subgroups.

Low Sensitivity of BinaxNOW RSV in Infants

BACKGROUND

Respiratory syncytial virus (RSV) is a major cause of hospitalization in infants. Early detection of RSV can optimize clinical management and minimize use of antibiotics. BinaxNOW RSV (BN) is a rapid antigen detection test that is widely used. We aimed to validate the sensitivity of BN in hospitalized and nonhospitalized infants against the gold standard of molecular diagnosis.

METHODS

We evaluated the performance of BN in infants with acute respiratory tract infections with different degrees of disease severity. Diagnostic accuracy of BN test results were compared with molecular diagnosis as reference standard.

RESULTS

One hundred sixty-two respiratory samples from 148 children from October 2017 to February 2019 were studied. Sixty-six (40.7%) samples tested positive for RSV (30 hospitalizations, 31 medically attended episodes not requiring hospitalization, and 5 nonmedically attended episodes). Five of these samples tested positive with BN, leading to an overall sensitivity of BN of 7.6% (95% confidence interval [CI], 3.3%-16.5%) and a specificity of 100% (95% CI, 96.2%-100%). Sensitivity was low in all subgroups.

CONCLUSIONS

We found a low sensitivity of BN for point-of-care detection of RSV infection. BinaxNOW RSV should be used and interpreted with caution.

Presumed Risk Factors and Biomarkers for Severe Respiratory Syncytial Virus Disease and Related Sequelae: Protocol for an Observational Multicenter, Case-Control Study From the Respiratory Syncytial Virus Consortium in Europe (RESCEU)

Respiratory syncytial virus (RSV) is the leading viral pathogen associated with acute lower respiratory tract infection and hospitalization in children < 5 years of age worldwide. While there are known clinical risk factors for severe RSV infection, the majority of those hospitalized are previously healthy infants. There is consequently an unmet need to identify biomarkers that predict host response, disease severity, and sequelae. The primary objective is to identify biomarkers of severe RSV acute respiratory tract infection (ARTI) in infants. Secondary objectives include establishing biomarkers associated with respiratory sequelae following RSV infection and characterizing the viral load, RSV whole-genome sequencing, host immune response, and transcriptomic, proteomic, metabolomic and epigenetic signatures associated with RSV disease severity. Six hundred thirty infants will be recruited across 3 European countries: the Netherlands, Spain, and the United Kingdom. Participants will be recruited into 2 groups: (1) infants with confirmed RSV ARTI (includes upper and lower respiratory tract infections), 500 without and 50 with comorbidities; and (2) 80 healthy controls. At baseline, participants will have nasopharyngeal, blood, buccal, stool, and urine samples collected, plus complete a questionnaire and 14-day symptom diary. At convalescence (7 weeks ± 1 week post-ARTI), specimen collection will be repeated. Laboratory measures will be correlated with symptom severity scores to identify corresponding biomarkers of disease severity.

CLINICAL TRIALS REGISTRATION

NCT03756766.

Simultaneous Viral Whole-Genome Sequencing and Differential Expression Profiling in Respiratory Syncytial Virus Infection of Infants

Targeted metagenomics using strand-specific libraries with target enrichment is a sensitive, generalized approach to pathogen sequencing and transcriptome profiling. Using this method, we recovered 13 (76%) complete human respiratory syncytial virus (RSV) genomes from 17 clinical respiratory samples, reconstructed the phylogeny of the infecting viruses, and detected differential gene expression between 2 RSV subgroups, specifically, a lower expression of the P gene and a higher expression of the M2 gene in RSV-A than in RSV-B. This methodology can help to relate viral genetics to clinical phenotype and facilitate ongoing population-level RSV surveillance and vaccine development. Clinical Trials Registration. NCT03627572 and NCT03756766.

Respiratory Syncytial Virus Consortium in Europe (RESCEU) Birth Cohort Study: Defining the Burden of Infant Respiratory Syncytial Virus Disease in Europe

BACKGROUND

Respiratory syncytial virus (RSV) causes significant morbidity and mortality in infants worldwide. Although prematurity and cardiopulmonary disease are risk factors for severe disease, the majority of infants hospitalized with RSV are previously healthy. Various vaccines and therapeutics are under development and expected to be available in the near future. To inform the use of these new vaccines and therapeutics, it is necessary to determine the burden of RSV disease in Europe. We will prospectively follow-up a birth cohort to obtain incidence data on RSV acute respiratory tract infection (ARTI).

METHODS

Multicenter prospective study of a birth cohort consisting of 10 000 healthy infants, recruited during 3 consecutive years. RSV associated hospitalization in the first year of life will be determined by questionnaires and hospital chart reviews. A nested cohort of 1000 infants will be actively followed. In case of ARTI, a respiratory sample will be collected for RSV molecular diagnosis.

RESULTS

The primary outcome is the incidence rate of RSV-associated hospitalization in the first year of life. In the active cohort the primary outcome is RSV associated ARTI and MA-ARTI.

CONCLUSIONS

We will provide key information to fill the gaps in knowledge about the burden of RSV disease in healthy infants.

CLINICAL TRIALS REGISTRATION

NCT03627572.

Biomarkers for Disease Severity in Children Infected With Respiratory Syncytial Virus: A Systematic Literature Review

BACKGROUND

Clinical manifestations of respiratory syncytial virus (RSV) infection vary widely from mild, self-limiting illness to severe life-threatening disease. There are gaps in knowledge of biomarkers to objectively define severe disease and predict clinical outcomes.

METHODS

A systematic search was performed, 1945-March 2019 in databases Ovid Medline, Embase, Global health, Scopus, and Web of Science. Risk of bias was assessed using the Cochrane tool.

RESULTS

A total of 25 132 abstracts were screened and studies were assessed for quality, risk of bias, and extracted data; 111 studies met the inclusion criteria. RSV severity was correlated with antibody titers, reduced T and B cells, dysregulated innate immunity, neutrophil mobilization to the lungs and blood, decreased Th1 response, and Th2 weighted shift. Microbial exposures in respiratory tract may contribute to neutrophil mobilization to the lungs of the infants with severe RSV compared with mild RSV disease.

CONCLUSIONS

Although a wide range of biomarkers have been associated with RSV disease severity, robust validated biomarkers are lacking. This review illustrates the broad heterogeneity of study designs and high variability in the definition of severe RSV disease. Prospective studies are required to validate biomarkers. Additional research investigating epigenetics, metabolomics, and microbiome holds promise for novel biomarkers.

Age-dependent Interactions Among Clinical Characteristics, Viral Loads and Disease Severity in Young Children With Respiratory Syncytial Virus Infection

BACKGROUND

Age-dependent differences in clinical presentation and viral loads in infants and young children with respiratory syncytial virus (RSV) infection, and their correlation with disease severity are poorly defined.

METHODS

Previously healthy children <2 years old with mild (outpatients) and severe (inpatients) RSV infection were enrolled and viral loads measured by polymerase chain reaction in nasopharyngeal swabs. Patients were stratified by age in 0-<3, 3-6 and >6-24 months, and multivariable analyses were performed to identify clinical and viral factors associated with severe disease.

RESULTS

From 2014 to 2018, we enrolled 534 children with RSV infection, 130 outpatients with mild RSV infection and 404 inpatients with severe RSV disease. Median duration of illness was 4 days for both groups, yet viral loads were higher in outpatients than in inpatients (P < 0.001). In bivariate analyses, wheezing was more frequent in outpatients of older age (>3 months) than in inpatients (P < 0.01), while fever was more common in inpatients than outpatients (P < 0.01) and its frequency increased with age. Adjusted analyses confirmed that increased work of breathing and fever were consistently associated with hospitalization irrespective of age, while wheezing in infants >3 months, and higher RSV loads in children >6-24 months were independently associated with reduced disease severity.

CONCLUSIONS

Age had a significant impact defining the interactions among viral loads, specific clinical manifestations and disease severity in children with RSV infection. These observations highlight the importance of patient stratification when evaluating interventions against RSV.

Testing and Psychometric Validation of a Pediatric Instrument to Self-Assess Symptoms of the Common Cold

OBJECTIVES

Given the lack of validated patient-reported outcomes (PRO) instruments assessing cold symptoms, a new pediatric PRO instrument was developed to assess multiple cold symptoms: the Child Cold Symptom Questionnaire (CCSQ). The objective of this research was to evaluate the measurement properties of the CCSQ.

METHODS

This observational study involved daily completion of the self-report CCSQ by children aged 6-11 years in their home for 7 days. These data were used to develop a scoring algorithm and item-scale structure and evaluate the psychometric properties of the resulting scores. Analyses included evaluation of item and dimensionality performance (item response distributions and confirmatory factor analysis) and assessment of test-retest reliability in stable patients, construct validity (convergent and known groups validity), and preliminary responsiveness. Qualitative exit interviews in a subgroup of the children with colds and their parents were conducted.

RESULTS

More than 90% of children had no missing data during the testing period, reflecting an excellent completion rate. For most items, responses were distributed across the options, with approximately normal distributions. Test-retest reliability was adequate, with intra-class correlation coefficients ranging from 0.63 to 0.83. A logical pattern of correlations with the validated Strep-PRO instrument provided evidence supporting convergent validity. Single- and multi-item symptom scores distinguished between children who differed in their cold severity based on global ratings, providing evidence of known groups validity. Preliminary evidence indicates the CCSQ is responsive to changes over time.

CONCLUSIONS

The findings demonstrate that the CCSQ items and multi-item scores provide valid and reliable patient-reported measures of cold symptoms in children aged 6-11 years. They provide strong evidence supporting the validity of these items and multi-item scores for inclusion as endpoints in clinical trials to evaluate the efficacy of cold medicines.

Use of the ReSVinet Scale for parents and healthcare workers in a paediatric emergency service: a prospective study

INTRODUCTION

Most scales for acute respiratory infection (ARI) are limited to healthcare worker (HCW) use for clinical decision-making. The Respiratory Syncytial Virus network (ReSVinet) Scale offers a version for parents that could potentially help as an early warning system.

OBJECTIVE

To determine whether or not the ReSVinet Scale for ARI in infants can be reliably used by HCWs and parents in an emergency service.

METHODS

A prospective study was done of infants with ARI who were admitted to a paediatric emergency room to assess the ReSVinet Scale when used by faculty (paediatric doctor-professors), residents (doctors doing their first specialty in paediatrics) and parents. Spearman's correlation and a weighted kappa coefficient were used to measure interobserver agreement. Internal consistency was also tested by Cronbach's alpha test.

RESULTS

Overall, 188 patients, 58% male, were enrolled. A Spearman's correlation of 0.92 for faculty and resident scoring and 0.64 for faculty or resident and parent scoring was found. The weighted kappa coefficients were 0.78 for faculty versus residents, 0.41 for faculty versus parents, and 0.41 for residents versus parents. Cronbach's alpha test was 0.67 for faculty, 0.62 for residents and 0.69 for parents.

CONCLUSION

There was good correlation in the ReSVinet scores between health professionals when used in the paediatric emergency area. Agreement between parents and health professionals was found to be more variable. Future studies should focus on finding ways to improve its reliability when used by parents before the scale is used in the emergency room.

Nebulised ALX-0171 for respiratory syncytial virus lower respiratory tract infection in hospitalised children: a double-blind, randomised, placebo-controlled, phase 2b trial

BACKGROUND

Respiratory syncytial virus (RSV) is the most common cause of severe lower respiratory tract infection, with a high global health burden. There are no effective treatments available. ALX-0171 is a novel trivalent Nanobody with antiviral properties against RSV. We aimed to assess the safety and antiviral activity of nebulised ALX-0171 in children admitted to hospital with RSV lower respiratory tract infection.

METHODS

This double-blind, randomised, placebo-controlled, phase 2b trial was done in 50 hospital paediatric departments across 16 countries. Previously healthy children aged between 28 days to younger than 24 months who were admitted to hospital with RSV acute severe lower respiratory tract infection were randomly assigned in three sequential safety cohorts (3:1) to receive nebulised ALX-0171 (cohort 1 received 3 mg/kg, cohort 2 received 6 mg/kg, and cohort 3 received 9 mg/kg) or placebo once daily for 3 days using web-based randomisation in the sequential safety part (first block size 12, subsequently four). In a parallel part of the study, participants (cohort 4) were randomly assigned (parallel 1:1:1:1) to receive nebulised ALX-0171 3 mg/kg, 6 mg/kg, 9 mg/kg, or placebo (blocks of eight by restricted randomisation). Study drug masking was by two consecutive nebulisations (each either ALX-0171 or placebo) depending on assigned treatment group. The primary outcome was to evaluate time for the RSV viral load to drop to below quantifiable limit, measured by plaque assay on mid-turbinate nasal swabs. Safety, clinical efficacy, pharmacokinetics, viral load by RT-qPCR, and immunogenicity were secondary outcomes. Analysis, including of the primary outcome, was by modified intention to treat (participants receiving at least one dose of study drug as assigned), and safety was assessed in all children who received at least one administration of study drug, as treated. This trial is registered with EudraCT, 2016-001651-49.

FINDINGS

Between Jan 10, 2017, and April 26, 2018, 175 children (median age 4·8 months [IQR 2·0-10·8]), received at least one dose of study drug (45 received 3 mg/kg of ALX-0171, 43 received 6 mg/kg of ALX-0171, 45 received 9 mg/kg of ALX-0171, and 42 received placebo; the modified intention-to-treat population) commencing at a mean 3·3 days (SD 1·1) from symptom onset. Median time for the viral load to drop to below quantifiable limit on plaque assay was significantly faster for the 3 mg/kg group (median 14·2 h [IQR 5·0-28·0]), 6 mg/kg group (5·1 h [4·7-28·5]), and 9 mg/kg group (5·1 h [4·6-5·9]) than the placebo group (46·1 h [25·2-116·7]; hazard ratio [HR] all ALX-0171 groups vs placebo 2·6 [1·7-3·9]; p<0·0001). Median time for the viral load to drop below quantification limit with RT-qPCR was 95·9 h (IQR 26·7 to not estimable) for the placebo group (n=35) versus 49·4 h (25·1 to 351·4) for all ALX-0171 groups (n=118). Clinical outcomes were not improved by ALX-0171 compared with placebo, with no difference in time to clinical response (oxygen saturation >92% for 4 h in room air and adequate oral feeding) in ALX-0171 groups and the placebo group (median 43·8 h [IQR 21·7-68·5] vs 47·9 h [22·5-76·4]; HR 1·1 [95% CI 0·8-1·6]) or change in the global severity score from baseline to 5 h post-dose on day 2 (-4 [IQR -6 to -2] vs -4 [-6 to -1]; difference in least-squares mean -0·45 [95% CI -1·39 to 0·49]). Serum concentrations of ALX-0171 on day 2 exceeded the concentration estimated to give full RSV neutralisation in the lung at 6 mg/kg and 9 mg/kg doses. Treatment-emergent antidrug antibodies were detected at day 14 in 46 (34%) of 135 patients who received ALX-0171 and ten (26%) of 39 patients who received placebo. Serious adverse events were reported in five (13%) of 40 children in the placebo group and ten (7%) of 135 children in all ALX-0171 groups, leading to study drug discontinuation in three children (two in the 3 mg/kg group and one in the 6 mg/kg group). 13 of 15 serious adverse events (three of four in the 3 mg/kg group, two of three in the 6 mg/kg group, three of three in the 9 mg/kg group, and five of five in the placebo group) were related to worsening respiratory status, and none were considered to be related to the study drug.

INTERPRETATION

Antivirals against RSV might be unable to improve clinical course once RSV lower respiratory tract infection is established. Future studies of RSV antivirals should focus on earlier intervention and more precise measurement of objective outcomes before the onset of significant lower respiratory tract inflammation.

FUNDING

Ablynx, a Sanofi Company.

Metabolomic Profiling of Infants With Recurrent Wheezing After Bronchiolitis

Background

Bronchiolitis is associated with a greater risk of developing recurrent wheezing, but with currently available tools, it is impossible to know which infants with bronchiolitis will develop this condition. This preliminary prospective study aimed to assess whether urine metabolomic analysis can be used to identify children with bronchiolitis who are at risk of developing recurrent wheezing.

Methods

Fifty-two infants <1 year old treated in the emergency department at University Hospital of Padova for acute bronchiolitis were enrolled (77% tested positive for respiratory syncytial virus [RSV]). Follow-up visits were conducted for 2 years after the episode of bronchiolitis. Untargeted metabolomic analyses based on mass spectrometry were performed on urine samples collected from infants with acute bronchiolitis. Data modeling was based on univariate and multivariate data analyses.

Results

We distinguished children with and those without postbronchiolitis recurrent wheeze, defined as ≥3 episodes of physician-diagnosed wheezing. Pathway overrepresentation analysis pointed to a major involvement of the citric acid cycle (P < .001) and some amino acids (lysine, cysteine, and methionine; P ≤ .015) in differentiating between these 2 groups of children.

Conclusion

This is the first study showing that metabolomic profiling of urine specimens from infants with bronchiolitis can be used to identify children at increased risk of developing recurrent wheezing.

Nebulised hypertonic saline in children with bronchiolitis admitted to the paediatric intensive care unit: A retrospective study

AIM

Bronchiolitis is one of the most common lower respiratory tract infections in young children, associated with significant morbidity, but limited therapeutic options. Nebulised hypertonic saline (HS) has been a supportive treatment until current guidelines advised against its routine use. Accordingly, the University Hospital of Antwerp recently changed their policies to stop using it, allowing us to evaluate retrospectively if HS influences the duration of respiratory support. Because, to our knowledge, the effect of HS on children with severe bronchiolitis admitted to a paediatric intensive care unit (PICU) has not been studied yet, we aimed to investigate the effect in this specific patient group.

METHODS

Retrospective study including children up to the age of 2, admitted to the PICU with bronchiolitis from October 2013 until March 2016. The primary end point is the duration of respiratory support, including high flow nasal cannula, continuous positive airway pressure and invasive ventilation.

RESULTS

A total of 104 children admitted to the PICU with bronchiolitis were included, with an average age of 3.4 months. In respiratory syncytial virus (RSV) positive patients, the use of nebulised HS was correlated with a decrease in the duration of respiratory support and the length of stay by factors 0.72 (P = 0.01) and 0.81 (P = 0.04), respectively.

CONCLUSIONS

A significant correlation was found between the use of HS and a decreased duration of respiratory support and admission in the PICU in patients with RSV bronchiolitis. This finding may warrant new prospective studies investigating HS specifically in children with severe bronchiolitis.

Delivery of ALX-0171 by inhalation greatly reduces respiratory syncytial virus disease in newborn lambs

Respiratory syncytial virus (RSV) is a common cause of acute lower respiratory disease in infants and young children worldwide. Currently, treatment is supportive and no vaccines are available. The use of newborn lambs to model hRSV infection in human infants may provide a valuable tool to assess safety and efficacy of new antiviral drugs and vaccines. ALX-0171 is a trivalent Nanobody targeting the hRSV fusion (F) protein and its therapeutic potential was evaluated in newborn lambs infected with a human strain of RSV followed by daily ALX-0171 nebulization for 3 or 5 consecutive days.

Colostrum-deprived newborn lambs were infected with hRSV-M37 before being treated by daily nebulization with either ALX-0171 or placebo. Two different treatment regimens were examined: day 1–5 or day 3–5 post-infection. Lambs were monitored daily for general well-being and clinical parameters. Respiratory tissues and bronchoalveolar lavage fluid were collected at day 6 post-inoculation for the quantification of viral lesions, lung viral titers, viral antigen and lung histopathology.

Administration by inhalation of ALX-0171 was well-tolerated in these hRSV-infected newborn lambs. Robust antiviral effects and positive effects on hRSV-induced lung lesions and reduction in symptoms of illness were noted. These effects were still apparent when treatment start was delayed and coincided with peak viral loads (day 3 post-infection) and at a time point when signs of RSV disease were apparent. The latter design is expected to have high translational value for planned clinical trials. These results are indicative of the therapeutic potential of ALX-0171 in infants.

Respiratory syncytial virus hospitalization in children in northern Spain

OBJECTIVES

Understanding respiratory syncytial virus (RSV) morbidity may help to plan health care and future vaccine recommendations. We aim to describe the characteristics and temporal distribution of children diagnosed with RSV admitted in a Spanish hospital.

METHODS

Descriptive study for which the hospital discharges of children < 5 years of age with RSV infection were analyzed. The information was extracted from the hospital discharge database of a reference pediatric hospital in northern Spain for the 2010-2011 to 2014-2015 RSV seasons.

RESULTS

Six hundred and forty-seven hospitalizations of children with RSV infection were analyzed, 94% of which occurred between the second week of November and the last week of March. Most children (72%) were under one year of age and 95% were previously healthy infants. Infants born from October to December had the highest risk of hospitalization in the first year of life. The median length of hospital stay of children with and without comorbidities was six and three days, respectively. 6.5% of the hospitalized cases were admitted to the pediatric intensive care unit; this percentage was higher among children < 2 months (adjusted odds ratio 4.15; 95% confidence interval: 1.37-12.61) or with comorbidities (adjusted odds ratio 4.15; 95% confidence interval: 1.53-11.28). The case lethality was 0.3%.

CONCLUSIONS

The risk of hospitalizations for RSV is high during the first year of life and increases among infants born in the fall. Being under two months of age and presenting comorbidities are the main risk factors associated to pediatric intensive care unit admission.

Bronchiolitis in children: The Saudi initiative of bronchiolitis diagnosis, management, and prevention (SIBRO)

Bronchiolitis is the leading cause of admissions in children less than two years of age. It has been recognized as highly debated for many decades. Despite the abundance of literature and the well-recognized importance of palivizumab in the high risk groups, and despite the existence of numerous, high-quality, recent guidelines on bronchiolitis, the number of admissions continues to increase. Only supportive therapy and few therapeutic interventions are evidence based and proved to be effective. Since Respiratory Syncytial Virus (RSV) is the major cause of bronchiolitis, we will focus on this virus mostly in high risk groups like the premature babies and children with chronic lung disease and cardiac abnormalities. Further, the prevention of RSV with palivizumab in the high risk groups is effective and well known since 1998; we will discuss the updated criteria for allocating infants to this treatment, as this medication is expensive and should be utilized in the best condition. Usually, diagnosis of bronchiolitis is not challenging, however there has been historically no universally accepted and validated scoring system to assess the severity of the condition. Severe RSV, especially in high risk children, is unique because it can cause serious respiratory sequelae. Currently there is no effective curative treatment for bronchiolitis. The utility of different therapeutic interventions is worth a discussion.

Whole Exome Sequencing reveals new candidate genes in host genomic susceptibility to Respiratory Syncytial Virus Disease

Respiratory syncytial virus (RSV) is an important cause of serious lower respiratory tract disease in infants. Several studies have shown evidence pointing to the genome of the host as an important factor determining susceptibility to respiratory disease caused by RSV. We sequenced the complete exomes of 54 patients infected by RSV that needed hospitalization due to development of severe bronchiolitis. The Iberian sample (IBS) from The 1000 Genomes Project (1000G) was used as control group; all the association results were pseudo-replicated using other 1000G-European controls and Spanish controls. The study points to SNP rs199665292 in the olfactory receptor (OR) gene OR13C5 as the best candidate variant (P-value = 1.16 × 10-12; OR = 5.56). Genetic variants at HLA genes (HLA-DQA1, HLA-DPB1), and in the mucin 4 gene (MUC4) also emerge as susceptibility candidates. By collapsing rare variants in genes and weighing by pathogenicity, we obtained confirmatory signals of association in the OR gene OR8U1/OR8U8, the taste receptor TAS2R19, and another mucin gene (MUC6). Overall, we identified new predisposition variants and genes related to RSV infection. Of special interest is the association of RSV to olfactory and taste receptors; this finding is in line with recent evidence pointing to their role in viral infectious diseases.

[Validation study of an acute bronchiolitis severity scale to determine admission to a Paediatric Intensive Care Unit]

INTRODUCTION

At present, there are few validated scoring tests for assessing acute bronchiolitis (AB) severity, and limited information on their test power. The aim of the present study is to evaluate the validity of an acute bronchiolitis severity score (ABSS) to help in deciding PICU admission.

PATIENTS AND METHOD

Prospective, descriptive, observational study of previously healthy infants under 1 year of age with AB, where the ABSS was used to compare severity as regards the need for PICU admission. The sample size was estimated as at least 175 patients. The research team was trained in the use of ABSS. All patients in the study were evaluated with ABSS daily, as well as in the case of clinical deterioration. The initial and maximum ABSS scores were contrasted to the need for PICU admission. A receiver operative curve was constructed, and the area under the curve was calculated, and the optimum point of sensitivity / specificity was estimated.

RESULTS

The study included a total of 190 patients (male / female: 58% / 42%). PICU was required in 11 (6%). The mean± SD ABSS-maximal score for patients who required and did not require PICU was 10.55± 1.12 and 6.35± 2.3, respectively (P<.001). The AUC for ABSS-maximal was 0.94 (P<.001, 95% CI: 0.90-0.98). The optimal cut-off point was set at ≥10 points for a sensitivity of 82% and a specificity of 91%.

CONCLUSIONS

ABSS estimates the severity of AB regarding the need for PICU admission, with a sensitivity and specificity of clinical usefulness.

Clinical respiratory scales: which one should we use?

INTRODUCTION

There are countless clinical respiratory scales for acute dyspnoea. Most healthcare professionals choose one based on previous personal experience or following local practice, unaware of the implications of their choice. The lack of critical comparisons between those different tools has been a widespread problem that only recently has begun to be addressed via score validation studies. Here we try to assess and compare the quality criteria of measurement properties of acute dyspnoea scores. Areas covered: A literature review was conducted by searching the PubMed database. Forty-five documents were deemed eligible as they reported the use or building of clinical scales, using at least two parameters, and applied these to an acute episode of respiratory dyspnoea. Our primary focus was the description of the validity, reliability and utility of 41 suitable scoring instruments. Differences in sample selection, study design, rater profiles and potential methodological shortcomings were also addressed. Expert commentary: All acute dyspnoea scores lack complete validation. In particular, the areas of measurement error and interpretability have not been addressed correctly by any of the tools reviewed. Frequent modification of pre-existing scores (in items composition and/or name), differences in study design and discrepancies in reviewed sources also hinder the search for an adequate tool.

Bacteremia in Children Hospitalized with Respiratory Syncytial Virus Infection

BACKGROUND

The risk of bacteremia is considered low in children with acute bronchiolitis. However the rate of occult bacteremia in infants with RSV infection is not well established. The aim was to determine the actual rate and predictive factors of bacteremia in children admitted to hospital due to confirmed RSV acute respiratory illness (ARI), using both conventional culture and molecular techniques.

METHODS

A prospective multicenter study (GENDRES-network) was conducted between 2011-2013 in children under the age of two admitted to hospital because of an ARI. Among those RSV-positive, bacterial presence in blood was assessed using PCR for Meningococcus, Streptococcus pneumoniae, Haemophilus influenzae, Streptococcus pyogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, in addition to conventional cultures.

RESULTS

66 children with positive RSV respiratory illness were included. In 10.6% patients, bacterial presence was detected: H. influenzae (n = 4) and S. pneumoniae (n = 2). In those patients with bacteremia, there was a previous suspicion of bacterial superinfection and had received empirical antibiotic treatment 6 out of 7 (85.7%) patients. There were significant differences in terms of severity between children with positive bacterial PCR and those with negative results: PICU admission (100% vs. 50%, P-value = 0.015); respiratory support necessity (100% vs. 18.6%, P-value < 0.001); Wood-Downes score (mean = 8.7 vs. 4.8 points, P-value < 0.001); GENVIP scale (mean = 17 vs. 10.1, P-value < 0.001); and length of hospitalization (mean = 12.1 vs. 7.5 days, P-value = 0.007).

CONCLUSION

Bacteremia is not frequent in infants hospitalized with RSV respiratory infection, however, it should be considered in the most severe cases.