Defining the Epidemiology and Burden of Severe Respiratory Syncytial Virus Infection Among Infants and Children in Western Countries

Bronchiolitis: Impact of Age and Etiology on Morbidity and Mortality in Previously Healthy Critically Ill Children

This retrospective, multicenter observational study analyzed data from 257 children under 2 years old admitted with viral bronchiolitis to pediatric intensive care units (PICU) at Wolfson Children's Hospital and UFHealth Shands Children's Hospital from January 2020 to March 2022. The study explores viral etiologies and their associations with hospital length of stay (H-LOS), PICU length of stay (P-LOS), and severity markers and scores. Younger age was associated with longer H-LOS and P-LOS (P < .001). Respiratory syncytial virus (RSV) was associated with younger age but not with H-LOS when controlled for age. RSV's impact on H-LOS varied by age (P = .018). Markers of severity did not differ between patients infected with RSV versus those without RSV, or in patients with co-infection versus single infection. In our population, pSOFA performed better than PELOD-2 in disease severity assessment.

Impact of Nirsevimab immunoprophylaxis on professional exhaustion during two epidemics of respiratory syncytial virus

OBJECTIVE

We aimed to assess the impact of introducing immunoprophylaxis against respiratory syncytial virus in infants (healthy infants up to 6 months of age and vulnerable children up to 24 months) on the professional quality of life of pediatric healthcare providers, and to analyze its association with factors such as sex, age, work experience, workplace setting, professional role, and involvement in pediatric emergency departments.

METHODS

We conducted an observational, analytical, cross-sectional, multicenter study in Valencia and Castellon Health Departments. The Professional Quality of Life Scale (ProQOL-21) was used to assess compassion satisfaction, burnout, and secondary traumatic stress, the latter two being components of compassion fatigue. Data were collected during two bronchiolitis periods: 2022-2023 (pre-Nirsevimab) and 2023-2024 (post-Nirsevimab). These three dimensions were analyzed across both periods and in relation to demographic and professional variables.

RESULTS

A total of 213 surveys were collected (113 pre-Nirsevimab and 100 post-Nirsevimab). The results revealed a significant decrease in burnout and secondary traumatic stress, along with an increase in compassion satisfaction. Improvements were particularly notable among professionals working in emergency departments, hospitals, those under 35 years of age, women, and those with less than 10 years of work experience. No significant improvements were observed in men or residents across any of the dimensions.

IMPLICATIONS FOR PRACTICE

The implementation of immunoprophylaxis against respiratory syncytial virus has not only improved patient outcomes but has also positively impacted the emotional well-being of pediatric healthcare providers, highlighting the importance of implementing preventive strategies to support healthcare professionals.

Recent advances in natural products and derivatives with antiviral activity against respiratory syncytial virus (RSV)

Respiratory syncytial virus (RSV) is a widespread viral infection that causes millions of high-risk illnesses annually. Medicinal herbs such as ginseng root, echinacea purpurea, and radix astragali have a positive effect on antiviral activity by preventing viral adhesion, syncytial development, inhibiting viral internalization, relieving respiratory inflammation, strengthening the immune system, and stimulating the release of interferons. The potential benefits of natural products in terms of lower costs, better patient outcomes, and fewer adverse effects are discussed. This review examines the current evidence on the prevention and control of RSV with natural ingredients and the challenges and opportunities in clinical practice.

Genotypic and phenotypic characterisation of respiratory syncytial virus after nirsevimab breakthrough infections: a large, multicentre, observational, real-world study

BACKGROUND

Nirsevimab, a long-acting monoclonal antibody, has been approved for the prevention of respiratory syncytial virus (RSV) infection in infants. In France, more than 210 000 single doses were administered in infants younger than 1 year during the 2023-24 season. In this context, the selection and spread of escape variants might be a concern. Here, we aimed to characterise RSV associated with breakthrough infection.

METHODS

We did a multicentre, national, observational study in France during the 2023-24 RSV season in RSV-infected infants (aged <1 year) who either received or did not receive a dose of nirsevimab before their first RSV season. We excluded infants with insufficient information about nirsevimab treatment or without parental consent. We used respiratory samples collected in each laboratory for full-length RSV RNA sequencing to analyse changes in the nirsevimab binding site Ø. We tested clinical RSV isolates for neutralisation by nirsevimab. We analysed F candidate substitutions by fusion-inhibition assay.

FINDINGS

Of the 695 RSV infected infants, we analysed 545 (78%) full-length RSV genome sequences: 260 (48%) from nirsevimab-treated breakthrough infections (236 [91%] RSV-A and 24 [9%] RSV-B) and 285 (52%) from untreated RSV-infected infants (236 [83%] RSV-A and 49 [17%] RSV-B). Analysis of RSV-A did not reveal any substitution in site Ø known to be associated with resistance to nirsevimab. Two (8%) of 24 RSV-B breakthrough infections had resistance-associated substitutions: F:N208D (dominant resistance-associated substitution) and a newly described F:I64M plus F:K65R combination (minority resistance-associated substitution), both of which induced high levels of resistance in the fusion-inhibition assay.

INTERPRETATION

This study is, to the best of our knowledge, the largest genotypic and phenotypic surveillance study of nirsevimab breakthrough infections to date. Nirsevimab breakthrough variants remain very rare despite the drug's widespread use. The detection of resistance-associated substitutions in the RSV-B F protein highlights the importance of active molecular surveillance.

FUNDING

ANRS Maladies Infectieuses Emergentes and the French Ministry of Health and Prevention.

Economic Impact of Respiratory Syncytial Virus Infections in Children Under 5 Years of Age Attending Primary Care in Italy: A Prospective Cohort Study in Two Regions

BACKGROUND

Accurate cost estimates of respiratory syncytial virus (RSV) infections in primary care are limited, despite the majority of cases being managed in this setting. This study aims to estimate healthcare costs for children with RSV in primary care and the related costs of parental work absence.

METHODS

Children < 5 years of age with symptoms of acute respiratory infections were recruited via primary care paediatricians in two Italian regions for a prospective cohort study on the RSV burden in primary care, during the 2019/2020 winter. Healthcare utilization, medication use and parental work absence were assessed during a 14-day follow-up period. Average costs were estimated per RSV episode for the overall study population, as well as per age group.

RESULTS

Two hundred ninety three children were recruited, of which 119 tested RSV positive (41%) and 109 were included. In total, 89% of RSV-positive children (97/109) had ≥ 1 repeat paediatrician visit(s), and 10% (11/109) visited the ED. The mean number of repeat visits was 3.8 (SD: 4.0) and the mean duration of work absence 4.0 days (SD: 5.0). Average costs per RSV episode were €730 (95% CI: €691-€771), with direct medical costs accounting for 25% (€183 [95% CI: €174-€191]) and indirect costs related to work absence for 75% (€547 [95% CI: €509-€587]).

CONCLUSIONS

Costs associated with RSV infections in young children in primary care are considerable due to a substantial number of paediatrician visits and high rates of parental work absence. These costs are important to include in decision-making regarding the implementation of new RSV immunization strategies in national immunization programmes.

Inpatient service utilization amongst infants diagnosed with Respiratory Syncytial Virus infection (RSV) in the United States

INTRODUCTION

Respiratory syncytial virus (RSV) is the leading cause of hospitalization among US infants. Characterizing service utilization during infant RSV hospitalizations may provide important information for prioritizing resources and interventions.

OBJECTIVE

The objective of this study was to describe the procedures and services received by infants hospitalized during their first RSV episode in their first RSV season, in addition to what proportion of infants died during this hospitalization.

METHODS

In this retrospective observational study, we analyzed three different administrative claims datasets to examine healthcare service utilization during RSV hospitalizations among infants. The study population included infants born between July 2016 and February 2020 who experienced an RSV episode during their first RSV season and had an associated inpatient hospitalization. We stratified infants into three comorbidity groups: healthy term, palivizumab-eligible, and other comorbidities. Outcomes included extracorporeal membrane oxygenation, supplemental oxygen use (in-hospital and post-discharge), mechanical ventilation (invasive and non-invasive), chest imaging, infant mortality, length of inpatient stay, intensive care unit (ICU) admission, and number of days in the ICU.

RESULTS

Chest imaging was the most frequently administered procedure during RSV-associated hospitalizations, with approximately 34-38% of infants receiving it. Around one-quarter of infants were admitted to the ICU during their first RSV hospitalization. Median lengths of stay in the hospital were 3-4 days, extending to 4-6 days in the presence of ICU admission. Palivizumab-eligible infants had higher utilization of healthcare services and spent more time in the hospital or ICU compared to healthy infants or those with other comorbidities.

CONCLUSIONS

This study provides insights into the utilization of healthcare services during RSV hospitalizations among infants. Understanding service utilization patterns can aid in improved management and resource allocation for infants in the United States, ultimately contributing to better outcomes and reduced healthcare costs overall. However, likely under-ascertainment of ventilation and oxygen-related services in insurance claims remains an impediment to studying these outcomes.

Economic and clinical burden associated with respiratory syncytial virus and impact of universal immunization with nirsevimab in Italy

Objectives

To describe the seasonal respiratory syncytial virus (RSV) burden in Italy considering the current prophylaxis strategy with palivizumab recommended only for high-risk infants (representing only 4.4% of an estimated birth cohort) and to evaluate the potential benefits of a new prophylaxis strategy targeting all infants with nirsevimab.

Methods

A static decision analytic model previously used in the US was adapted to evaluate the RSV-related health and cost outcomes associated with nirsevimab versus standard of care (SoC) for the prevention of RSV medically attended lower respiratory tract infections (RSV-MA-LRTIs). Monthly probabilities of RSV infections, health events, mortality, and complications associated with RSV infections were obtained from the literature. Costs associated with each event were obtained using the available literature and through real-world data analysis of National Hospital Discharge Records.

Results

For one RSV season, in the current SoC, the model estimated 216,100 RSV-MA-LRTIs, 15,121 associated complications, and 16 RSV-deaths-corresponding to an economic burden of approximately €50.5 million related to RSV-MA-LRTIs management, €10.9 million associated with potential complications due to RSV and €3 million in lost productivity due to RSV-deaths. Nirsevimab is expected to prevent 100,208 RSV-MA-LRTIs, 6,969 complications, and 6 deaths due to RSV infections, corresponding to an economic saving of about €23.3, €5, and €1.2 million, respectively.

Conclusion

Nirsevimab is a new prophylaxis strategy that helps to protect all infants against RSV disease and could substantially reduce the clinical and economic burden of RSV in Italy in infants experiencing their first RSV season.

Respiratory syncytial virus immunization patterns in Germany, 2015-2020

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection (LRTI) in infants and young children worldwide. Using routine statutory health insurance claims data including patients from all regions of Germany, we investigated the health-care resource use and costs associated with RSV prophylaxis with palivizumab in Germany. In the database, infants from the birth cohorts 2015-2019 eligible for palivizumab immunization were identified using codes of the 10th revision of the International Classification of Diseases (ICD-10). Health-care resource use and costs related to immunization were determined by inpatient and outpatient administrations. Over the study period, only 1.3% of infants received at least one dose of palivizumab in their first year of life. The mean number of doses per immunized infant was 4.6. From a third-party payer perspective, the mean costs of palivizumab per infant who received at least one dose in the first year of life was €5,435 in the birth cohorts 2015-2019. Despite the substantial risk of severe RSV infection, we found low rates of palivizumab utilization. Novel preventive interventions, featuring broader indications and single-dose administration per season, contribute to mitigating the burden of RSV disease across a more extensive infant population.

[Nirsevimab effectiveness against hospital admission for respiratory syncytial virus bronchiolitis in infants]

OBJECTIVE

Respiratory syncytial virus (RSV) bronchiolitis is the leading cause of hospitalization in infants. This season, a long half-life monoclonal antibody (Nirsevimab) is available to prevent this disease for all infants born from 1 April-30 September to 2023 and all those born during RSV season (October2023- March 2024). The aim of this study was to evaluate the impact of the implementation of this antibody on RSV admissions in a tertiary hospital.

METHODS

Observational, retrospective and analytical study. All patients <6 months in October admitted for bronchiolitis at 2 time points were included: T1 or Pre-nirsevimab time: 1 September 2015-30 September 2023 and T2 or Nirsevimab time: 1 October-31 December 2023. Total admissions due to any cause of infants <6 months in the same period were used as the reference population. To assess the impact of the implementation of nirsevimab, we calculated the reduction in the percentage of admissions due to RSV with respect to total admissions in both periods, and also in the 2023-2024 season we calculated the double negative test to calculate the effectiveness of the intervention (1-Odds ratio) x 100.

RESULTS

In infants under 6 months of age, we found significant differences in the number of admissions for RSV bronchiolitis between the last season and the previous 7 seasons [574/1195 (48%) vs 6/138 (4.3%); p<0.01, RPI: 91%). In the 2023/2024 season, the effectiveness of nirsevimab in preventing admission for RSV bronchiolitis in children under 6 months of age was 85% (CI 95%: 32-97%).

CONCLUSIONS

The implementation of nirsevimab has had an important impact on the number of hospital admissions for RSV bronchiolitis. There were no differences in the severity of bronchiolitis.

Biology of human respiratory syncytial virus: Current perspectives in immune response and mechanisms against the virus

Human respiratory syncytial virus (hRSV) remains a leading cause of morbidity and mortality in infants, young children, and older adults. hRSV infection's limited treatment and vaccine options significantly increase bronchiolitis' morbidity rates. The severity and outcome of viral infection hinge on the innate immune response. Developing vaccines and identifying therapeutic interventions suitable for young children, older adults, and pregnant women relies on comprehending the molecular mechanisms of viral PAMP recognition, genetic factors of the inflammatory response, and antiviral defense. This review covers fundamental elements of hRSV biology, diagnosis, pathogenesis, and the immune response, highlighting prospective options for vaccine development.

Parental knowledge about respiratory syncytial virus and attitudes toward infant immunization with monoclonal antibodies in France

BACKGROUND AND AIM

Respiratory syncytial virus (RSV) is a leading cause of hospitalization of infants with respiratory infections. A new immunization using monoclonal antibodies (mAbs) may offer protection against RSV infections. A study was conducted across eight countries to gain insight into parental awareness of RSV, their sources of child health information, and attitudes toward infant immunization against RSV using mAbs. This paper presents the findings from France.

METHODS

In 2021, a survey was conducted in eight countries among expecting and current parents with children younger than 24 months of age. Eligible respondents included parents who were open to childhood immunizations, i.e., they had given or planned to give their children "all," "most," or "some" immunizations.

RESULTS

In France, the survey respondents had high adoption rates for childhood immunizations. Key drivers behind these high rates were the desire to protect their children from severe diseases and adherence to mandatory immunizations, whereas concerns about safety were the main barriers. While general practitioners and pediatricians were key sources of advice on child health, many parents also requested information about immunizations from health authorities and nurses. Sources of advice varied with parental age, gender, educational level, and income. The majority of parents had no knowledge about mAbs or passive immunization, and the overall awareness of RSV was low. When informed about RSV and mAbs, most parents held neutral to positive attitudes toward nirsevimab for their infants if recommended by a healthcare professional and/or included in the immunization program. These findings were further confirmed by the 60 %-80 % uptake rates of nirsevimab following the introduction in September 2023.

Key Challenges to Understanding the Burden of Respiratory Syncytial Virus in Older Adults in Southeast Asia, the Middle East, and North Africa: An Expert Perspective

INTRODUCTION

Respiratory syncytial virus (RSV) is a common, highly contagious pathogen and a leading cause of serious illness among infants and older adults. While existing scientific evidence has predominantly focused on the epidemiology and disease burden of RSV in infants, data in older adults remain limited in some countries, including those in Southeast Asia (SEA) and the Middle East and North Africa (MENA) region. Here, we outline the key challenges for understanding the burden of RSV in older adults in SEA and the MENA region and we propose opportunities for improving understanding and eventually reducing the impact of RSV.

MAIN FINDINGS AND CONCLUSIONS

A key challenge identified by the expert group, particularly in older adults, is a lack of awareness (among healthcare professionals, policy makers, and the public) of RSV burden and the associated risks for severe outcomes. This is often confounded by the complexities of underdiagnosis, surveillance limitations, and comorbidities. To address these issues, we suggest medical education initiatives for physicians in SEA and the MENA region to better understand the need to protect older adults from RSV, and encourage more widespread routine testing to better understand the burden of RSV. We also recommend surveillance studies in these regions to provide comprehensive and accurate epidemiological data on RSV in older adults. Finally, in the absence of current surveillance data in these regions, we propose extrapolating existing global data and local pediatric data to inform the likely burden of RSV in older adults. A graphical abstract is available with this article.

Trends in SARS-CoV-2-related pediatric hospitalizations reported to the Canadian Nosocomial Infection Surveillance Program, March 2020 to December 2022

Objective

This study describes trends in COVID-19 hospitalizations and healthcare-associated (HA) COVID-19 in Canada among pediatric (age <18 years) patients during pre-Omicron and Omicron-dominant periods.

Design

Prospective surveillance for COVID-19 infection.

Setting

The Canadian Nosocomial Infection Surveillance Program is a sentinel surveillance system with 45 hospitals providing COVID-19 data on pediatric patients, including all 13 pediatric tertiary care facilities in Canada.

Patients

Pediatric patients hospitalized with laboratory-confirmed COVID-19 at a participating hospital between March 1, 2020, and December 31, 2022.

Methods

Analyzed case-level data on pediatric patients with COVID-19, including demographics, acquisition source, and outcomes.

Results

Among 5,143 pediatric cases, the majority (81%) were reported during the Omicron-dominant period (beginning December 26, 2021). However, a lower proportion required intensive care during the Omicron wave (11% vs 14%, P < 0.05); no difference in mortality was observed. Of those patients admitted to hospital due to COVID-19 (n = 2,700), 45% had at least one pre-existing comorbidity. The majority (90%) of patients with HA-COVID-19 were reported during the Omicron period. There was no difference in mortality between patients with HA and community-associated (CA) infection, although a greater proportion of CA infections led to intensive care unit admission (6% vs 13%, P < 0.01).

Conclusions

Surveillance findings indicate that both HA- and CA-COVID-19 hospitalizations in Canada increased among pediatric patients following the emergence of the Omicron variant, although disease severity decreased. Pre-existing health conditions were common among pediatric patients hospitalized with COVID-19, highlighting the importance of preventing severe illness in this sub-population.

Healthcare resource utilisation and costs in infants with confirmed respiratory syncytial virus infections: a national population cohort study

BACKGROUND

Respiratory syncytial virus (RSV) is the leading cause of severe respiratory infections in infants worldwide, significantly affecting their health and contributing to the global healthcare burden. We aimed to examine healthcare resource utilisation patterns and costs for infants under one year old with confirmed RSV infection across subgroups of different gestational ages and health conditions and the cost implications of RSV infections over time, thereby demonstrating the economic burden of the disease.

METHODS

This retrospective cohort study utilised nationwide claims data from the Korea Health Insurance Review and Assessment Service for infants under one year of age with confirmed RSV infection in the first year of life from January 2017 to April 2022. The infants were stratified into three subgroups based on their gestational age and health status: unhealthy preterm, healthy preterm, and full-term infants. A descriptive analysis was conducted to estimate healthcare utilization by type of resource and costs related to the treatment of RSV.

RESULTS

Out of 93,585 RSV infections identified, 31,206 patients met the inclusion criteria; these included 963 unhealthy preterm, 1,768 healthy preterm and 28,475 full-term infants. In our study, 76.3% of the infants with confirmed RSV infection required intensive care, including hospitalisation and more critical interventions such as intensive care unit (ICU) or mechanical ventilation (MV). The total average cost of RSV management was notably higher for unhealthy preterm infants ($ 6,325; 95% confidence interval (CI): $ 5,484-7,165) than for healthy preterm ($ 1,134; 95% CI: $ 1,006 - 1,261) and full-term infants ($ 606; 95% CI: 583-630). Our findings confirmed a significant epidemiological and economic burden, with infants at greater risk-shorter gestational age and poorer health conditions. Furthermore, we observed a marked increase in the total average cost of RSV management during COVID-19, reflecting the complex interplay between RSV and pandemic-related healthcare dynamics.

CONCLUSION

Our findings provide evidence for the significant economic burden of RSV infection among infants, with considerable disparities based on gestational age and health status subgroups. However, RSV prevention policies should also recognise that healthy preterm or full-term infants who receive intensive care face a significant disease burden.

Burden of disease and cost of illness of infants less than 6 months of age hospitalised with respiratory syncytial virus in Denmark - a 10-year national register-based study

BACKGROUND

Respiratory syncytial virus (RSV) is the most common cause of hospitalisation in infants aged ≤ 6 months in Western countries. Nearly 1,500 infants under six months of age are hospitalised with RSV annually in Denmark. This nationwide study describes the healthcare resource utilisation and costs related to RSV hospitalisation in this vulnerable age group.

METHODS

RSV cases were identified in the Danish National Patient Register. Infants were included if they at the age of 0-5 months had a (1) respiratory related hospital admission (duration > 12 h), (2) within 10 days of a positive RSV test, (3) between January 2013 and December 2022. Each case was matched with five individuals never diagnosed with RSV on age, sex, region of residence, birth (pre/full term), number of siblings < 7 years old, and parents' education. An episode of RSV was defined as the seven days prior to hospitalisation to 30 days after initial hospitalisation. Study outcomes included contacts with hospital and primary care, and total healthcare costs defined as the sum cost of hospital care, primary care, and prescription medicine. Cost and contacts attributable to RSV was calculated in a diff-in-diff framework, as the difference between case and reference group.

RESULTS

The study population comprised of 8,428 RSV cases and 41,725 reference individuals. Cases generated 1.58 (p < 0.001) attributable inpatient contacts, 0.84 (p < 0.001) outpatient contacts, and 1.19 (p < 0.001) primary care contacts during their RSV episode. An additional 0.6 (p < 0.001) inpatient, 1.08 (p < 0.001) outpatient and 2.42 (p < 0.001) primary care contacts were attributed to RSV in the year following the RSV episode. Total cost of an RSV episode was EUR 2,997 (p < 0.001) with an additional EUR 1,428 (p < 0.001) in the following year.

CONCLUSION

RSV hospitalisations of infants are associated with substantial healthcare utilisation and costs. The same pattern was observed in the year following the RSV episode. If the new RSV prevention options are introduced nationwide, the overall burden of RSV is expected to be substantially reduced in the future.

Hospitalizations due to respiratory syncytial virus (RSV) infections in Germany: a nationwide clinical and direct cost data analysis (2010-2019)

PURPOSE

Clinical and direct medical cost data on RSV-related hospitalizations are relevant for public health decision-making. We analyzed nationwide data on RSV-coded hospitalizations from Germany in different age and risk groups.

METHODS

Assessment of RSV-coded hospitalizations (ICD-10-GM RSV-code J12.1/J20.5/J21.0 as primary discharge diagnosis) from 01/2010 to 12/2019, using remote data retrieval from the Hospital Statistics Database of the German Federal Statistical Office.

RESULTS

Overall, 205,352 RSV-coded hospitalizations (198,139 children < 18 years, 1,313 adults, 5,900 seniors > 59 years) were reported (median age < 1 year, IQR 0; 1; 56% males, 32% with RSV pneumonia). Annual median RSV-coded hospitalization incidence was 24.8/100,000 persons (IQR 21.3; 27.5); children reported a median incidence of 145.8 (IQR 130.9; 168.3). Between 2010 and 2019, hospitalization incidence increased 1.7-fold/15.1-fold/103-fold in children/adults/seniors. Adults and seniors reported higher rates of underlying chronic conditions, complications, and intensive care treatment than children; of 612 in-hospital fatalities, 103/51/458 occurred in children/adults/seniors. Per-patient mean costs varied between 3286€ ± 4594 in 1-4-year-olds and 7215€ ± 13,564 among adults. Increased costs were associated with immune disorders (2.55-fold increase compared to those without), nervous system disorders (2.66-fold), sepsis (7.27-fold), ARDS (12.85-fold), intensive care (4.60-fold) and ECMO treatment (16.88-fold).

CONCLUSION

The economic burden of RSV-related hospitalizations in Germany is substantial, even when only considering cases with RSV-coded as the primary discharge diagnosis. Children represented the vast majority of RSV-coded hospitalizations. However, adults and seniors hospitalized for RSV were at a higher risk of severe complications, required more costly treatments, and had higher fatality rates; although their RSV-coded hospitalization incidence showed a clear upward trend since 2017, their true hospitalization incidence is still likely to be underestimated due to lack of routine RSV testing in these age groups. Hence, new treatments and vaccines for RSV ideally should also target adults and seniors in addition to children.

Inpatient burden of respiratory syncytial virus (RSV) in Switzerland, 2003 to 2021: an analysis of administrative data

BackgroundRespiratory syncytial virus (RSV) is a leading cause of acute respiratory infections and hospitalisations in infants (age < 1 year) and young children. Little is known on RSV epidemiology and related inpatient healthcare resource use (HCRU) in Switzerland.AimTo explore RSV-related hospitalisations, inpatient HCRU and medical costs in all age groups, and risk factors for infant hospitalisations in Switzerland.MethodsWe used national hospital registry data from 2003 to 2021 identifying RSV cases with ICD-10-GM codes, and described demographic characteristics, HCRU and associated medical costs of RSV inpatients. The effect of risk factors on infant hospitalisation was estimated with logistic regression.ResultsWe observed a general increase and biannual pattern in RSV hospitalisations between 2003/04 and 2018/19, with 3,575 hospitalisations in 2018/19 and 2,487 in 2019/20 before numbers declined in 2020/21 (n = 902). Around two thirds of all hospitalisations occurred in infants. Mean (median) age was 118 (85) days in hospitalised infants and 74 (77) years in hospitalised adult patients (> 18 years); 7.2% of cases required intensive care unit stay. Mean inpatient medical costs were estimated at EUR 8,046. Most (90.8%) hospitalised infants with RSV were born after 35 weeks of gestation without bronchopulmonary dysplasia or congenital heart disease. Low birth weight, gestational age and congenital disorders were associated with a higher risk for hospitalisation.ConclusionsRSV leads to a substantial number of hospitalisations and peaks in hospital capacity utilisation. Measures to protect all infants from an RSV hospitalisation are essential in addressing this public health challenge.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Genome-wide Association Study of Susceptibility to Respiratory Syncytial Virus Hospitalization in Young Children <5 Years of age

BACKGROUND

Worldwide, respiratory syncytial virus (RSV) infections are among the most common causes of infant hospitalization. Host genetic factors influencing the risk and severity of RSV infection are not well known.

METHODS

We conducted a genome-wide association study (GWAS) to investigate single-nucleotide polymorphisms (SNPs) associated with severe RSV infections using a nested case-control design based on 2 Danish cohorts. We compared SNPs from 1786 children hospitalized with RSV to 45 060 controls without an RSV-coded hospitalization. We performed gene-based testing, tissue enrichment, gene-set enrichment, and a meta-analysis of the 2 cohorts. Finally, an analysis of potential associations between the severity of RSV infection and genetic markers was performed.

RESULTS

We did not detect any significant genome-wide associations between SNPs and RSV infection or the severity of RSV. We did find potential loci associated with RSV infections on chromosome 5 in 1 cohort but failed to replicate any signals in both cohorts.

CONCLUSIONS

Despite being the largest GWAS of severe RSV infection, we did not detect any genome-wide significant loci. This may be an indication of a lack of power or an absence of signal. Future studies might include mild illness and need to be larger to detect any significant associations.

Impact of twelve immunization-preventable infectious diseases on population health using disability-adjusted life years (DALYs) in Spain

BACKGROUND

The objective of this study is to estimate the burden of selected immunization-preventable infectious diseases in Spain using the Burden of Communicable Diseases in Europe (BCoDE) methodology, as well as focusing on the national immunization programme and potential new inclusions.

METHODS

The BCoDE methodology relies on an incidence and pathogen-based approach to calculate disease burden via disability-adjusted life year (DALY) estimates. It considers short and long-term sequelae associated to an infection via outcome trees. The BCoDE toolkit was used to populate those trees with Spanish-specific incidence estimates, and de novo outcome trees were developed for four infections (herpes zoster, rotavirus, respiratory syncytial virus [RSV], and varicella) not covered by the toolkit. Age/sex specific incidences were estimated based on data from the Spanish Network of Epidemiological Surveillance; hospitalisation and mortality rates were collected from the Minimum Basic Data Set. A literature review was performed to design the de novo models and obtain the rest of the parameters. The methodology, assumptions, data inputs and results were validated by a group of experts in epidemiology and disease modelling, immunization and public health policy.

RESULTS

The total burden of disease amounted to 163.54 annual DALYs/100,000 population. Among the selected twelve diseases, respiratory infections represented around 90% of the total burden. Influenza exhibited the highest burden, with 110.00 DALYs/100,000 population, followed by invasive pneumococcal disease and RSV, with 25.20 and 10.57 DALYs/100,000 population, respectively. Herpes zoster, invasive meningococcal disease, invasive Haemophilus influenza infection and hepatitis B virus infection ranked lower with fewer than 10 DALYs/100,000 population each, while the rest of the infections had a limited burden (< 1 DALY/100,000 population). A higher burden of disease was observed in the elderly (≥ 60 years) and children < 5 years, with influenza being the main cause. In infants < 1 year, RSV represented the greatest burden.

CONCLUSIONS

Aligned with the BCoDE study, the results of this analysis show a persisting high burden of immunization-preventable respiratory infections in Spain and, for the first time, highlight a high number of DALYs due to RSV. These estimates provide a basis to guide prevention strategies and make public health decisions to prioritise interventions and allocate healthcare resources in Spain.

How Does the Burden of Respiratory Syncytial Virus Compare to Influenza in Spanish Adults?

BACKGROUND

Respiratory syncytial virus (RSV) and influenza infections cause significant annual morbidity and mortality worldwide in at-risk populations. This study is aimed at assessing hospital burden and healthcare resource utilization (HRU) of RSV and influenza in adults in Spain.

METHODS

Data were obtained from the Projected Hospitalisation Database of inpatient episodes (ages: younger adults 18-50 and 51-64 years; older adults 65-74, 75-84, and ≥ 85 years) during 2015, 2017, and 2018 in Spanish public hospitals. Incidence, mean hospitalization, and HRU assessments, including length of stay (LOS), intensive care unit (ICU) usage, and age-standardized mortality rates, were collected and stratified by age group, with analyses focusing on the adult population (≥ 18 years old).

RESULTS

Mean hospitalization rate in the population across all years was lower in individuals with RSV versus influenza (7.2/100,000 vs. 49.7/100,000 individuals). ICU admissions and median LOS were similar by age group for both viruses. Age-standardized mortality was 6.3/100,000 individuals and 6.1/100,000 individuals in patients with RSV and influenza, respectively, and mortality rates were similar in older adults (≥ 65 years) for both viruses.

CONCLUSIONS

RSV and influenza infection were associated with considerable HRU. There is a substantial disease burden for RSV infection in older adults ≥ 65 years. While RSV hospitalization rates in adults reported here appeared lower than influenza, RSV is still underdiagnosed in the hospital setting and its incidence might be similar to, or higher than, influenza.

Epidemiology of respiratory syncytial virus in hospitalized children over a 9-year period and preventive strategy impact

Background: Respiratory Syncytial Virus (RSV) is the primary cause of respiratory infections and hospitalizations in young children globally, leading to substantial disease burden and mortality. The aim of the present study was to review and provide updates on how the SARS-CoV-2 pandemic have significantly influenced RSV epidemiology on hospitalized children due to RSV infection. A potential impact of the available preventive strategies on the same population were provided. Methods: All children aged 0-6 years hospitalized at Meyer Children's Hospital IRCCS for RSV infection from September 2014 to March 2023 were retrospectively recorded. Seasonal trends before and after SARS-CoV-2 pandemic, age distribution, ICU admission and co-infections, comorbidities and prematurity were retrieved. Predictions on the number of hospitalizations avoided by the deployment of different preventive strategies were provided. Results: A total of 1,262 children with RSV infection were included in the study. The 70% of them had less than 1 year-of-age at the moment of hospitalization and almost 50% less than 3 months. In the post-pandemic seasons, a 317% increase in the number of hospitalizations was recorded with a significant increase in older children compared to the pre-pandemic seasons. ICU support was required for 22% of children, the majority of whom were under 3 months of age. Almost 16% of hospitalized children were born preterm and only 27% of hospitalized children had prior comorbidities. The rate of comorbidities among RSV hospitalized children increased with age. Nirsevimab prophylaxis could have prevented more than 46% of hospitalizations in this cohort. A preventive strategy addressing also children aged 7 months to 6 years of age with co-existing comorbidities would increase that rate above 57%. Discussion: The identification of RSV hospitalization-related features is informing the decision-maker for the deployment of the wisest preventive approach on a population scale.

Epidemiology of Respiratory Syncytial Virus Hospitalizations in Poland: An Analysis from 2015 to 2023 Covering the Entire Polish Population of Children Aged under Five Years

BACKGROUND

Respiratory syncytial virus (RSV) is an important cause of childhood hospitalizations. The aim of the study was to estimate the rates of RSV-related hospitalizations in children aged less than 5 years in Poland.

METHODS

This retrospective observational cohort study was based on data obtained from the National Health Fund in Poland regarding all acute respiratory tract infections and RSV-coded admissions of children (age < 5 years) to public hospitals between July 2015 and June 2023. Patients were stratified based on the following age groups: 0-1 month, 2-3 months, 4-6 months, 7-12 months, 13-24 months, and 25-60 months.

RESULTS

The number of RSV-related hospitalizations increased every season, both before and through the ending phase of the coronavirus disease 2019 (COVID-19) pandemic. The COVID-19 pandemic was associated with a shift in the seasonality pattern of RSV infection. Hospitalization rates per 1000 inhabitants were the highest for children aged 0-12 months, reaching 47.3 in the 2022/23 season. Within this group, the highest hospitalization rate was observed for children aged 2-3 months-94.9 in the 2022/23 season. During the ending phase of the COVID-19 pandemic, the observed increase in admission rates was 2-, 4-, and 5-fold the pre-COVID rate for children aged <12 months, 12-24 months, and 25-60 months, respectively.

CONCLUSIONS

In Poland, RSV infections cause a significant burden in hospitalized children aged less than 5 years. RSV-related hospitalizations were most frequent in children aged less than 1 year. The COVID-19 pandemic was associated with a shift in the seasonality pattern of RSV infections. After the pandemic, more RSV-related hospitalizations were observed in older children (aged 13 months and older) vs. the pre-pandemic phase.

Outpatient respiratory syncytial virus infections and novel preventive interventions

PURPOSE OF REVIEW

With interventions to prevent respiratory syncytial virus (RSV) infection within reach, this review aims to provide healthcare professionals with the latest information necessary to inform parents and assess the potential impact of RSV prevention on everyday practice. We address frequently asked questions for parental counseling.

RECENT FINDINGS

Numerous studies emphasize the major burden of RSV on young children, parents, healthcare and society. In the first year of life, about 14% of healthy term infants visit a doctor and 2% require hospitalization due to RSV. In older children (1--5 years), RSV infections and associated morbidity (wheeze, acute otitis media) are major drivers of outpatient visits. A novel maternal RSV vaccine and long-acting mAb can provide protection during infants' first months of life. This maternal vaccine showed 70.9% efficacy against severe RSV infection within 150 days after birth; the mAb nirsevimab reduces medically attended RSV infections by 79.5% within 150 days after administration. Both gained regulatory approval in the USA (FDA) and Europe (EMA).

SUMMARY

Novel RSV immunizations hold promise to reduce the RSV burden in infants, with substantial impact on everyday practice. Tailored parental guidance will be instrumental for successful implementation. Awaiting pediatric vaccines, RSV infections beyond infancy will still pose a significant outpatient burden.

An epidemiological investigation of high-risk infants for Respiratory Syncytial Virus infections: a retrospective cohort study

BACKGROUND

Respiratory Syncytial Virus (RSV) infections may lead to severe consequences in infants born preterm with breathing problems (such as bronchopulmonary dysplasia (BPD) and respiratory distress syndrome (RDS)) or congenital heart diseases (CHD). Since studies investigating the influence of different gestational age (WGA) and concomitant specific comorbidities on the burden of RSV infections are scarce, the present study aimed to better characterize these high-risk populations in the Italian context.

METHODS

This retrospective, longitudinal and record-linkage cohort study involved infants born between 2017 and 2019 in Lazio Region (Italy) and is based on data extracted from administrative databases. Each infant was exclusively included in one of the following cohorts: (1) BPD-RDS (WGA ≤35 with or without CHD) or (2) CHD (without BPD and/or RDS) or (3) Preterm (WGA ≤35 without BPD (and/or RDS) or CHD). Each cohort was followed for 12 months from birth. Information related to sociodemographic at birth, and RSV and Undetermined Respiratory Agents (URA) hospitalizations and drug consumption at follow-up were retrieved and described.

RESULTS

A total of 8,196 infants were selected and classified as 1,084 BPD-RDS, 3,286 CHD and 3,826 Preterm. More than 30% of the BPD-RDS cohort was composed by early preterm infants (WGA ≤ 29) in contrast to the Preterm cohort predominantly constitute by moderate preterm infants (98.2%), while CHD infants were primarily born at term (83.9%). At follow-up, despite the cohorts showed similar proportions of RSV hospitalizations, in BPD-RDS cohort hospitalizations were more frequently severe compared to those occurred in the Preterm cohort (p<0.01), in the BPD-RDS cohort was also found the highest proportion of URA hospitalizations (p<0.0001). In addition, BPD-RDS infants, compared to those of the remaining cohorts, received more frequently prophylaxis with palivizumab (p<0.0001) and were more frequently treated with adrenergics inhalants, and glucocorticoids for systemic use.

CONCLUSIONS

The assessment of the study clinical outcomes highlighted that, the demographic and clinical characteristics at birth of the study cohorts influence their level of vulnerability to RSV and URA infections. As such, continuous monitoring of these populations is necessary in order to ensure a timely organization of health care system able to respond to their needs in the future.

No association between disease severity and respiratory syncytial virus subtypes RSV-A and RSV-B in hospitalized young children in Norway

OBJECTIVE

There is conflicting evidence whether subtypes of Respiratory syncytial virus have different seasonality or are differentially associated with clinical severity. We aimed to explore the associations between disease severity and RSV subtypes RSV-A and RSV-B and to describe the circulation of RSV subtypes pattern by season and age.

METHODS

Active prospective hospital surveillance for RSV-A and RSV-B in children <59 months of age was conducted during 2015-2018. All febrile children 12-59 months of age were enrolled, whereas children <12 months were eligible if presenting with fever or respiratory symptoms. Risk factors and upper and lower respiratory tract infection was identified by linkage to national registry data and analyzed using penalized maximum likelihood logistic regression.

RESULTS

Both RSV-A and B were found to co-circulate throughout all three study seasons, and no clear seasonal pattern was identified. Likewise, we found no association between sex or measures of severity with RSV-A or RSV-B. There was significantly more RSV-A than RSV-B among children with comorbidities.

CONCLUSIONS

No association was found between disease severity or sex and RSV subtypes RSV-A and RSV-B in hospitalized young children in Norway.

Vitamin D and viral infections: Infectious diseases, autoimmune diseases, and cancers

Viruses can cause many human diseases. Three types of human diseases caused by viruses are discussed in this chapter: infectious diseases, autoimmune diseases, and cancers. The infectious diseases included in this chapter include three respiratory tract diseases: influenza, COVID-19, and respiratory syncytial virus. In addition, the mosquito-borne dengue virus diseases are discussed. Vitamin D can reduce risk, severity, and mortality of the respiratory tract diseases and possibly for dengue virus. Many autoimmune diseases are initiated by the body's reaction to a viral infection. The protective role of vitamin D in Epstein-Barr virus-related diseases such as multiple sclerosis is discussed. There are a few cancers linked to viral infections. Such cancers include cervical cancer, head and neck cancers, Hodgkin's and non-Hodgkin's lymphoma, and liver cancer. Vitamin D plays an important role in reducing risk of cancer incidence and mortality, although not as strongly for viral-linked cancers as for other types of cancer.

Impact of COVID‑19 pandemic restrictions and subsequent relaxation on the prevalence of respiratory virus hospitalizations in children

BACKGROUND

The COVID-19 pandemic and the consequently adopted worldwide control measures have resulted in global changes in the epidemiology and severity of other respiratory viruses. We compared the number and severity of viral acute lower respiratory tract infection (ALRTI) hospitalizations and determined changes in causative respiratory pathogens before, during, and after the pandemic among young children in Qatar.

METHODS

In this single-center retrospective study, we reviewed data of children ≤ 36 months old who were admitted to Sidra Medicine in Qatar with a viral ALRTI during winter seasons (September-April) between 2019 and 2023. The study period was divided into three distinct seasons based on the pandemic-imposed restrictions as follows: (1) the period between September 2019 and April 2020 was considered the pre-COVID-19 pandemic season; (2) the periods between September 2020 and April 2021, and the period between January and April 2022 were considered the COVID-19 pandemic seasons; and (3) the periods between September 2022 and April 2023 was considered the post-COVID-19 pandemic season.

RESULTS

During the COVID-19 season, 77 patients were admitted, compared with 153 patients during the pre-COVID-19 season and 230 patients during the post-COVID-19 season. RSV was the dominant virus during the pre-COVID-19 season, with a detection rate of 50.9%. RSV infection rate dropped significantly during the COVID-19 season to 10.4% and then increased again during the post-COVID-19 season to 29.1% (P < 0.001). Rhinovirus was the dominant virus during the COVID-19 (39.1%) and post-COVID-19 seasons (61%) compared to the pre-COVID-19 season (31.4%) (P < 0.001). The average length of hospital stay was significantly longer in the post-COVID-19 season than in the pre-COVID-19 and COVID-19 seasons (P < 0.001). No significant differences in the pediatric intensive care unit (PICU) admission rate (P = 0.22), PICU length of stay (p = 0.479), or respiratory support requirements were detected between the three seasons.

CONCLUSION

Our study showed reduced viral ALRTI hospitalizations in Qatar during the COVID-19 pandemic with reduced RSV detection. An increase in viral ALRTI hospitalizations accompanied by a resurgence of RSV circulation following the relaxation of COVID-19 restrictions was observed without changes in disease severity.

Epidemiology of Bronchiolitis and Respiratory Syncytial Virus and Analysis of Length of Stay from 2015 to 2022: Retrospective Observational Study of Hospital Discharge Records from an Italian Southern Province before and during the COVID-19 Pandemic

BACKGROUND

Severe respiratory infections, including pneumonia or bronchiolitis, caused by RSV can range from mild upper respiratory tract infections to those leading to hospitalization and serious complications such as respiratory failure in children. High-risk groups, such as premature infants and infants with underlying medical conditions, have a higher susceptibility to severe RSV disease. We conducted a retrospective study from years 2015 to 2022 in the Local Health Authority (LHA) of Pescara that counts about 320,000 inhabitants, with the aim to evaluate the burden of RSV infection, focusing on the incidence, hospitalization, and characteristics that may prolong hospital stays.

METHODS

All hospitalizations from 2015 to 2022 were extracted from the hospital discharge record. The monthly hospitalization rates were calculated and standardized by gender and age for the population resident in the Province of Pescara on 1 January 2015.

RESULTS

During the study period, 31,837 admissions were reported among patients aged less than 6 years. Of those, 520 hospitalizations were referred for bronchiolitis. Monthly admission rates highlighted the seasonality of bronchiolitis admissions, with higher rates in the months from December to March in all study years included. The winter seasons of years 2021 and 2022 reported a surge in bronchiolitis incidence, with a rate of 4.0/1000 (95% CI 2.964-5.146) in December 2021 and 4.0 (95% CI 2.891-5.020) in December 2022.

CONCLUSIONS

Bronchiolitis represents an important cause of hospitalization among patients aged less than 6 years. The incidence was particularly increased during the winter seasons in years 2021 and 2022.

Epidemiology and clinical features of respiratory syncytial virus (RSV) infection in hospitalized children during the COVID-19 pandemic in Gorgan, Iran

Background and Aims

Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infection in infants and young children. Given the altered circulation patterns of respiratory viruses during the coronavirus disease pandemic-2019 (COVID-19), the study aimed to evaluate epidemiology and clinical features of RSV infections in hospitalized children during the COVID-19 pandemic in Gorgan, northeastern Iran. Molecular epidemiology studies on respiratory viral infections are necessary to monitor circulating viruses, disease severity, and clinical symptoms, in addition to early warning of new outbreaks.

Methods

Overall, 411 respiratory swab samples from hospitalized children from October 2021 to March 2022 were collected at Taleghani Children's Hospital, Gorgan, Iran. The incidence of RSV, as well as the circulating subgroups and genotypes, were investigated and confirmed using PCR methods. Additionally, all samples tested for severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2) and influenza, and demographic and clinical data were analyzed using SPSS software.

Results

The share of RSV, SARS-CoV-2, and influenza among hospitalized children with acute lower respiratory infections (ALRI) were 27%, 16.5%, and 4.1%, respectively. The RSV subgroup A (genotype ON1) was dominant over subgroup B (genotype BA9), with more severe clinical symptoms. Compared with the prepandemic era there were high numbers of hospitalized SARS-CoV-2 positive children and low numbers of other respiratory viruses. Despite this, the prevalence of ALRI-related RSV-disease among hospitalized children in our specialized pediatric center was higher than COVID-19 disease in the same cohort.

Conclusions

Studying the epidemiology of respiratory viruses and determining the circulating strains can contribute to effective infection control and treatment strategies.

Burden of disease of respiratory syncytial virus in infants, young children and pregnant women and people

Background

Passive immunization products for infants and pregnant women and people have sparked interest in understanding Canada's respiratory syncytial virus (RSV) burden. This rapid review examines RSV burden of disease in infants, young children and pregnant women and people.

Methods

Electronic databases were searched to identify studies and systematic reviews reporting data on outpatient visits, hospitalizations, intensive care unit admissions, deaths and preterm labour associated with RSV. We also contacted Canadian respiratory virus surveillance experts for additional data.

Results

Overall, 17 studies on infants and young children and 10 studies on pregnant women and people were included, in addition to primary surveillance data from one Canadian territory (Yukon). There were higher rates of medical utilization for infants than older children. Hospitalization rates were highest in infants under six months (more than 1% annually), with 5% needing intensive care unit admission, but mortality was low. Severe outcomes often occurred in healthy full-term infants and burden was higher than influenza. Respiratory syncytial virus attack rate was 10%-13% among pregnant women and people. Only one study found a higher hospitalization rate in pregnant women and people compared to non-pregnant women and people. Limited evidence was found on intensive care unit admission, death and preterm birth for pregnant women and people.

Conclusion

While risk of severe outcomes is larger in high-risk infants and children, healthcare burden is greatest in healthy term infants. The RSV severity for pregnant women and people appears to be similar to that for non-pregnant women and people.

Controlled Human Infection Challenge Studies with RSV

Despite considerable momentum in the development of RSV vaccines and therapeutics, there remain substantial barriers to the development and licensing of effective agents, particularly in high-risk populations. The unique immunobiology of RSV and lack of clear protective immunological correlates has held back RSV vaccine development, which, therefore, depends on large and costly clinical trials to demonstrate efficacy. Studies involving the deliberate infection of human volunteers offer an intermediate step between pre-clinical and large-scale studies of natural infection. Human challenge has been used to demonstrate the potential efficacy of vaccines and antivirals while improving our understanding of the protective immunity against RSV infection. Early RSV human infection challenge studies determined the role of routes of administration and size of inoculum on the disease. However, inherent limitations, the use of highly attenuated/laboratory-adapted RSV strains and the continued evolutionary adaptation of RSV limits extrapolation of results to present-day vaccine testing. With advances in technology, it is now possible to perform more detailed investigations of human mucosal immunity against RSV in experimentally infected adults and, more recently, older adults to optimise the design of vaccines and novel therapies. These studies identified defects in RSV-induced humoral and CD8+ T cell immunity that may partly explain susceptibility to recurrent RSV infection. We discuss the insights from human infection challenge models, ethical and logistical considerations, potential benefits, and role in streamlining and accelerating novel antivirals and vaccines against RSV. Finally, we consider how human challenges might be extended to include relevant at-risk populations.

Burden of Respiratory Syncytial Virus in the European Union: estimation of RSV-associated hospitalizations in children under 5 years

BACKGROUND

No overall estimate of respiratory syncytial virus (RSV)-associated hospitalizations in children aged under 5 years has been published for the European Union (EU). We aimed to estimate the RSV hospitalization burden in children aged under 5 years in EU countries and Norway, by age group.

METHODS

We collated national RSV-associated hospitalization estimates calculated using linear regression models via the RESCEU project for Denmark, England, Finland, Norway, the Netherlands, and Scotland, 2006-2018. Additional estimates were obtained from a systematic review. Using multiple imputation and nearest neighbor matching methods, we estimated overall RSV-associated hospitalizations and rates in the EU.

RESULTS

Additional estimates for 2 countries (France and Spain) were found in the literature. In the EU, an average of 245 244 (95% confidence interval [CI], 224 688-265 799) yearly hospital admissions with a respiratory infection per year were associated with RSV in children aged under 5 years, with most cases occurring among children aged under 1 year (75%). Infants aged under 2 months represented the most affected group (71.6 per 1000 children; 95% CI, 66.6-76.6).

CONCLUSIONS

Our findings will help support decisions regarding prevention efforts and represent an important benchmark to understand changes in the RSV burden following the introduction of RSV immunization programs in Europe.

Comparison of Easy-to-Use Bronchiolitis Scores in the Post-COVID-19 Era-An Observational Study

In the post-restrictions COVID-19 period, the incidence of bronchiolitis in infants has increased considerably. Several scores determine the degree of severity of the bronchiolitis episode, but few are clinician-friendly. The main aim of this research was to find the easy-to-use score that most accurately estimated the severity of patients' infections according to their clinical situations and most accurately predicted the need for hospital admission. An observational cross-sectional study was performed in a reference pediatric hospital during the post-restrictions period of the COVID-19 pandemic (2021 and 2022). A comparison was made between the severity estimate provided by five international acute bronchiolitis scales and the clinical severity of the acute bronchiolitis episode. Three hundred and seventy-seven patients participated in the investigation, with a mean age of 5.68 months; 68.7% of the participants had a mild episode of bronchiolitis, 24.5% had a moderate episode, and 6.9% had a severe episode. The severity estimated by the Tal scale modified by McCallum showed a statistically significant correlation with the clinical severity established by clinical criteria (0.836; p < 0.001). It showed a high correlation with other international scores, such as the Wang score (0.820; p < 0.05) and the Wood-Downes-Ferrés score (0.936; p < 0.001). In the multivariate analysis, the constituent variables of the modified Tal score appeared in the final model that predicts the need for hospital admission. In the context of increased incidence after COVID-19, the Tal score modified by McCallum is an easy-to-use measuring instrument that presents an excellent concordance with the clinical severity estimated at first care contact. It also offers a more significant prediction of the need for hospital admission.

Respiratory syncytial virus infection and novel interventions

The large global burden of respiratory syncytial virus (RSV) respiratory tract infections in young children and older adults has gained increased recognition in recent years. Recent discoveries regarding the neutralization-specific viral epitopes of the pre-fusion RSV glycoprotein have led to a shift from empirical to structure-based design of RSV therapeutics, and controlled human infection model studies have provided early-stage proof of concept for novel RSV monoclonal antibodies, vaccines and antiviral drugs. The world's first vaccines and first monoclonal antibody to prevent RSV among older adults and all infants, respectively, have recently been approved. Large-scale introduction of RSV prophylactics emphasizes the need for active surveillance to understand the global impact of these interventions over time and to timely identify viral mutants that are able to escape novel prophylactics. In this Review, we provide an overview of RSV interventions in clinical development, highlighting global disease burden, seasonality, pathogenesis, and host and viral factors related to RSV immunity.

Multicenter epidemiological investigation and genetic characterization of respiratory syncytial virus and metapneumovirus infections in the pre-pandemic 2018-2019 season in northern and central Italy

Respiratory syncytial virus (RSV) and human metapneumovirus (HMPV) cause a high burden of disease, particularly in children and the elderly. With the aim to add knowledge on RSV and HMPV infections in Italy, a prospective, multicenter study was conducted by eight centers of the Working Group on Respiratory Virus Infections (GLIViRe), from December 2018-April 2019. Weekly distribution and patients' demographic and clinical data were compared in 1300 RSV and 222 HMPV-positive cases. Phylogenetic analysis of the G-glycoprotein coding region was performed to characterize circulating strains. RSV positivity ranged from 6.4% in outpatients of all ages to 31.7% in hospitalized children; HMPV positivity was 4-1.2% with no age-association. RSV season peaked in February and ended in mid-April: HMPV circulation was higher when RSV decreased in early spring. RSV was more frequent in infants, whereas HMPV infected comparatively more elderly adults; despite, their clinical course was similar. RSV-B cases were two-thirds of the total and had similar clinical severity compared to RSV-A. Phylogenetic analysis showed the circulation of RSV-A ON1 variants and the predominance of RSV-B genotype BA10. HMPV genotype A2c was the prevalent one and presented insertions of different lengths in G. This first multicenter Italian report on seasonality, age-specific distribution, and clinical presentation of RSV and HMPV demonstrated their substantial disease burden in young patients but also in the elderly. These data may provide the basis for a national respiratory virus surveillance network.

RSV Burden and Its Impact on Pediatric Inpatient Bed Occupancy in Belgium: An Analysis of National Hospital Claims Data

BACKGROUND

Respiratory syncytial virus (RSV) infections represent a substantial burden on pediatric services during winter. While the morbidity and financial burden of RSV are well studied, less is known about the organizational impact on hospital services (ie, impact on bed capacity and overcrowding and variation across hospitals).

METHODS

Retrospective analysis of the population-wide Belgian Hospital Discharge Data Set for the years 2017 and 2018 (including all hospital sites with pediatric inpatient services), covering all RSV-associated (RSV-related International Classification of Diseases, 10th Version, Clinical Modification diagnoses) inpatient hospitalization by children under 5 years old as well as all-cause acute hospitalizations in pediatric wards.

RESULTS

RSV hospitalizations amount to 68.3 hospitalizations per 1000 children less than 1 year and 5.0 per 1000 children 1-4 years of age and are responsible for 20%-40% of occupied beds during the peak period (November-December). The mean bed occupancy rate over the entire year (2018) varies across hospitals from 22.8% to 85.1% and from 30.4% to 95.1% during the peak period. Small-scale pediatric services (<25 beds) are more vulnerable to the volatility of occupancy rates. Forty-six hospital sites have daily occupancy rates above 100% (median of 9 days). Only in 1 of 23 geographically defined hospital networks these high occupancy rates are on the same calendar days.

CONCLUSIONS

Pediatric services tend to be over-dimensioned to deal with peak activity mainly attributable to RSV. RSV immunization can substantially reduce pediatric capacity requirements. Enhanced collaboration in regional networks is an alternative strategy to deal with peaks and reduce capacity needs.

The disease burden of respiratory syncytial virus in Infants

PURPOSE OF REVIEW

To describe the current global burden of respiratory syncytial virus (RSV) in infants and its implications for morbidity, health resources and economic costs.

RECENT FINDINGS

New prophylactic therapies are on the horizon for RSV in the form of long-acting monoclonal antibodies suitable for healthy infants and maternal immunizations.

SUMMARY

Despite being responsible for significant global infant morbidity and mortality, until recently there have been no effective therapeutics available for healthy infants to protect them from RSV. Several new drugs are likely to be available within the next few years which could help relieve a huge burden on healthcare systems over the coming winters.

Human Respiratory Syncytial Virus Epidemiological Burden in Pediatric Outpatients in Italy: A Systematic Review

BACKGROUND

Human respiratory syncytial virus (hRSV) is a key contributor to lower respiratory tract infections (LRTIs), affecting children aged 0-5 years and often leading to outpatient visits, emergency department utilization, and hospitalization. With the development of hRSV vaccines for mitigation, understanding the epidemiological impact of hRSV infections among 0-5-year-old pediatric outpatients in Italy is crucial.

METHODS

This systematic review conducted searches on PubMed, Embase, Scopus, and the International HTA Database, yielding 20,845 English and Italian records from January 2000 to July 2022.

RESULTS

Six eligible articles were identified following inclusion and exclusion criteria. These studies demonstrated hRSV-positivity proportions ranging from 18% to 41% in pediatric outpatients with respiratory infections. However, data comparability was hindered by diverse diagnostic approaches, data sources, sample populations, and study designs. Notably, hRSV-positivity showed temporal variability, rising from 23.8% (2001-2002) to 40.6% (2019-2020). This trend could stem from evolving epidemiological factors, heightened clinician awareness in hRSV diagnosis, or more sensitive molecular techniques.

CONCLUSION

As the first review of its kind, this study underscores the need for more comprehensive data to inform effective preventive strategies against hRSV-related burdens in pediatric outpatients.

The Path Towards Effective Respiratory Syncytial Virus Immunization Policies: Recommended Actions

The respiratory syncytial virus (RSV) causes a substantial burden worldwide. After over six decades of research, there is finally a licensed immunization option that can protect the broad infant population, and other will follow soon. RSV immunization should be in place from season 2023/2024 onwards. Doing so requires thoughtful but swift steps. This paper reflects the view of four immunization experts on the efforts being made across the globe to accommodate the new immunization options and provides recommendations organized around five priorities: (I) documenting the burden of RSV in specific populations; (II) expanding RSV diagnostic capacity in clinical practice; (III) strengthening RSV surveillance; (IV) planning for the new preventive options; (V) achieving immunization targets. Overall, Spain has been a notable example of converting RSV prevention into a national desideratum and has pioneered the inclusion of RSV in some of the regional immunization calendars for infants facing their first RSV season.

Bronchiolitis in Infants; Five Years' Experience of a Teaching Hospital

Background

Bronchiolitis is a clinical syndrome affecting the lower respiratory tract of infants and toddlers <2 years old. Variability in clinical profile and response to therapy in children with Bronchiolitis calls for studying the different clinical aspects of local patient population.

Aim

The goal of our study is to determine the clinical presentation, past medical history, hospitalization course and prognosis in children below two years of age who have been hospitalized in King Fahad University Hospital over the last five years.

Materials and Methods

A retrospective chart review based on electronic health records of all Bronchiolitis-related hospitalization of infants and toddlers below two years of age, covering the period between January 1, 2015, to April 26, 2020.

Results

Out of a total of 446 children <2 years of age, 202 were female (45.4%), and 243 were male (54.6%). Although the length of hospital stay was almost equal between the sexes, there was a significant (p-value=0.01) increase in length of intensive care unit stay among females compared to males. Furthermore, there was a significant prolongation in the duration of ventilator usage among females (p value = 0.062). Out of fifty-five patients admitted to the ICU, 83.63% of them were 12 months of age and below.

Conclusion

Our results show a significant increase in length of ICU and ventilator use among females compared to males. It also shows that infants younger than 12 months account for most ICU admissions. These findings, among many others, may help pediatricians formulate a better diagnostic and therapeutic pathways.

Evaluation of Bronchiolitis in the Pediatric Population in the United States of America and Canada: A Ten-Year Review

Bronchiolitis is a well-known viral infection among the pediatric population, significantly impacting hospitalization rates. The COVID-19 pandemic profoundly affected respiratory viral infections, including bronchiolitis, as various mitigation measures were implemented. In this study, we analyzed bronchiolitis cases during the pandemic and post-pandemic period, aiming to identify changes in management guidelines and their incidence and management over the last 10 years. Moreover, we explored the relationship between bronchiolitis and COVID-19, a virus that gained rapid notoriety worldwide. By analyzing data from pediatric populations in Canada and the USA, we sought to understand the role of varying seasons in the peak periods of bronchiolitis infections. The comprehensive review's results will provide valuable insights into bronchiolitis dynamics within the context of the COVID-19 pandemic. Our aim is to better comprehend the interplay between bronchiolitis, COVID-19, and seasonal variations, ultimately contributing to a deeper understanding of this respiratory viral infection and informing future management strategies. Furthermore, these findings can assist healthcare professionals in preparing for and responding to potential fluctuations in bronchiolitis cases in the post-pandemic era.

Worldwide research trends on bronchiolitis in pediatrics

BACKGROUND

The COVID-19 pandemic has led to a significant increase in cases of bronchiolitis among children. As a result, there has been a corresponding increase in the number of publications on this topic. It is essential to examine the main areas of focus within the scientific literature to understand the current trends in research on pediatric bronchiolitis. This research aims to analyze the types of scientific advances related to pediatric bronchiolitis, the research trends being pursued, and the countries and research institutions leading these efforts. By understanding these aspects of bronchiolitis research, we can better understand the current state of knowledge and identify areas where further research is needed.

METHODS

To conduct a bibliometric analysis of the scientific literature on pediatric bronchiolitis, all relevant publications were retrieved from the Scopus database. The Scopus API and the SW VosViewer software with optimized modularity functions were used. This analysis was intended to provide a comprehensive overview of the current state of research on this topic, including the types of scientific advances being developed, the research trends being pursued, and the countries and research institutions leading these efforts.

RESULTS

A total of 3810 publications were reviewed. We observed an increasing number of publications, particularly in recent years. Of these, 73.7% were articles, 95% were written in English, and 29.4% were from the United States. The main keywords used in these publications included: human, bronchiolitis, child, preschool, preschool child, major clinical study, controlled study, pneumonia, asthma, adolescent, hospitalization, infant, and newborn. These keywords were grouped into six clusters: outpatient management, long-term consequences, etiology, intensive care management, diagnostic methods, and the main cluster, which focused on hospital treatment and clinical studies.

CONCLUSIONS

The bibliometric analysis of bronchiolitis research in pediatrics reveals that there has been a significant increase in the number of publications on this topic, particularly in recent years. Most of these publications are articles written in English and published in the United States. The main keywords used in these studies relate to various aspects of bronchiolitis, including diagnosis, treatment, and long-term consequences. The results of this analysis suggest that bronchiolitis is a topic of significant interest and concern for researchers and practitioners in the field of pediatrics and that further research is needed to improve our understanding and management of this condition.

Understanding Policy Decisions and Their Implications Regarding Preventive Interventions for Respiratory Syncytial Virus (RSV) Infection in Canadian Infants: A Primer for Nurses

Respiratory syncytial virus (RSV) is a leading cause of morbidity and hospitalization in young children, and prevention is the primary management strategy. At present, palivizumab, a monoclonal antibody providing immediate passive immunity, rather than a vaccine that induces active immunity, is the only preventive intervention used in routine practice internationally. In Canada, access varies across the country. Prophylaxis policies are mainly driven by cost-effectiveness analyses, and it is crucial that the full costs and benefits of any intervention are captured. Positive results from a new Canadian cost-effectiveness analysis of palivizumab will help address the current inequality in use while providing a framework for future models of RSV preventives. Nurses are the principal educators for parents about the risks of childhood RSV and optimal prevention via basic hygiene, behavioral and environmental measures, and seasonal prophylaxis. Nurses should be provided not only with regular, up-to-date, and accurate information on RSV and the clinical aspects of emerging interventions but be informed on the decision-making governing the use of preventive strategies.

Characterization of the humoral and cellular immunity induced by a recombinant BCG vaccine for the respiratory syncytial virus in healthy adults

Introduction

The human respiratory syncytial virus (hRSV) is responsible for most respiratory tract infections in infants. Even though currently there are no approved hRSV vaccines for newborns or infants, several candidates are being developed. rBCG-N-hRSV is a vaccine candidate previously shown to be safe in a phase I clinical trial in adults (clinicaltrials.gov identifier #NCT03213405). Here, secondary immunogenicity analyses were performed on these samples.

Methods

PBMCs isolated from immunized volunteers were stimulated with hRSV or mycobacterial antigens to evaluate cytokines and cytotoxic T cell-derived molecules and the expansion of memory T cell subsets. Complement C1q binding and IgG subclass composition of serum antibodies were assessed.

Results

Compared to levels detected prior to vaccination, perforin-, granzyme B-, and IFN-γ-producing PBMCs responding to stimulus increased after immunization, along with their effector memory response. N-hRSV- and mycobacterial-specific antibodies from rBCG-N-hRSV-immunized subjects bound C1q.

Conclusion

Immunization with rBCG-N-hRSV induces cellular and humoral immune responses, supporting that rBCG-N-hRSV is immunogenic and safe in healthy individuals.

Clinical trial registration

https://classic.clinicaltrials.gov/ct2/show/, identifier NCT03213405.

Impact of RSV test positivity, patient characteristics, and treatment characteristics on the cost of hospitalization for acute bronchiolitis in a French university medical center (2010-2015)

Background

In young children, respiratory syncytial virus (RSV)-related bronchiolitis is typically more severe than other respiratory tract infections, with a greater need for oxygen therapy and respiratory support. Few studies have compared the cost of hospitalization with regard to virological status. The objective of this study was to compare the costs of hospitalization for RSV-positive vs. RSV-negative bronchiolitis in a French university medical center between 2010 and 2015.

Methods

The cost models were compared using conventional goodness-of-fit criteria. Covariates included the characteristics of the patients, pre-existing respiratory and non-respiratory comorbidities, superinfections, medical care provided, and the length of stay.

Results

RSV was detected in 679 (58.3%) of the 1,164 hospital stays by children under 2 years with virological data. Oxygen therapy and respiratory support were twice as frequent for the RSV-positive cases. The median hospitalization cost was estimated at €3,248.4 (interquartile range: €2,572.1). The cost distribution was positively skewed with a variation coefficient (CV = standard deviation/mean) greater than one (mean = €4,212.9, standard deviation = €5,047, CV = 1.2). In univariate analyses, there was no significant cost difference between the RSV-positive and RSV-negative cases. In the best multivariate model, the significant positive effect of RSV positivity on cost waned after the introduction of medical care variables and the length of stay. The results were sensitive to the specification of the model.

Conclusions

It was impossible to firmly conclude that hospitalization costs were higher for the RSV-positive cases.

Clinical and economic hospital burden of acute respiratory infection (BARI) due to respiratory syncytial virus in Spanish children, 2015-2018

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory infection (ALRI) in children, causing frequent outpatient visits and hospitalizations. Our study aimed to describe the clinical and direct economic burden of ALRI hospitalizations related to RSV in children in Spain and the characteristics of patients and their episodes. In this retrospective study, ALRI hospitalizations in children aged < 5 years for 2015-2018 were reviewed using anonymized administrative public hospital discharge data from Spain. Three case definitions were considered: (a) RSV-specific; (b) RSV-specific and unspecified acute bronchiolitis (RSV-specific and bronchiolitis); and (c) RSV-specific and unspecified ALRI (RSV-specific and ALRI). The study reported a mean of 36,743 yearly admissions potentially due to RSV, resulting in a mean annual cost of €87.1 million. RSV-specific codes accounted for 39.2% of cases, unspecified acute bronchiolitis for 20.1%, and other unspecified ALRI codes for the remaining 40.6%. The mean hospitalization rate per 1,000 children was 55.5 in the first year of life, 16.0 in the second, and 5.4 between 24 and 59 months. A considerable proportion of cases occurred in children under two years old (> 80.4%) and even during the first year of life (> 61.7%). Otherwise healthy children accounted for 92.9% of hospitalizations and 83.3% of costs during the period. Children born preterm accounted for 1.3% of hospitalizations and 5.7% of costs. The findings revealed that RSV still contributes to a high burden on the Spanish health care system. Children under one year of age and otherwise healthy term infants accounted for most of the substantial clinical and economic burden of RSV. Current evidence potentially underestimates the true epidemiology and burden of severe RSV infection; thus, further studies focusing on the outpatient setting are needed.

Hospitalization for bronchiolitis in children aged ≤ 1year, Southern Italy, year 2021: need for new preventive strategies?

BACKGROUND

Bronchiolitis is a major cause of hospitalization in infants, particularly in the first six months of life, with approximately 60-80% of admissions due to respiratory syncytial virus (RSV) infection. Currently, no prophylactic options are available for healthy infants. The present study aimed at describing the demographic, clinical, and epidemiological characteristics of infants hospitalized for bronchiolitis in the Apulia region of Italy in 2021.

METHODS

From January to December 2021, data on children aged 0-12 months admitted for bronchiolitis in nine neonatal or pediatric units covering 61% of pediatric beds of hospitals in the Apulia region of Italy were analyzed. Demographic data, comorbidities, need for oxygen support, length of hospital stay, palivizumab administration, and outcomes were collected. For the purpose of the analysis, patients were divided into those aged 0-3 months and > 3 months. A multivariate logistic regression model was used to explore associations between the need for oxygen support and sex, age, comorbidities, history of prematurity, length of hospital stay, and palivizumab administration.

RESULTS

This study included 349 children aged 0-12 months admitted for bronchiolitis, with a peak of hospitalization in November (7.4 cases/1,000 children). Of these patients, 70.5% were RSV positive, 80.2% were aged 0-3 months, and 73.1% required oxygen support. Moreover, 34.9% required observation in the sub-intensive care unit, and 12.9% in the intensive care unit. Of the infants who required intensive care, 96.9% were aged 0-3 months and 78.8% were born at term. Three patients required mechanical ventilation and one, who required Extra Corporeal Membrane Oxygenation, died. Children aged 0-3 months were more likely to show dyspnea, need oxygen support, and have a longer hospital stay.

CONCLUSIONS

The present study showed that almost all of the children who required intensive care support were aged ≤ 3 months and most were born at term. Therefore, this age group remains the highest risk group for severe bronchiolitis. Preventive measures such as single-dose monoclonal antibody immunoprophylaxis, and maternal and childhood vaccination against RSV, may reduce the high public health burden of 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.