RSV Prevention in All Infants: Which Is the Most Preferable Strategy?

Antibody-mediated protection against respiratory syncytial virus in children

Respiratory syncytial virus (RSV) is a major global pathogen, causing lower respiratory tract disease in at-risk populations including young children. Antibodies form a crucial layer of protection from RSV disease, particularly in immunologically naïve infants. Such antibodies are derived from the mother via transplacental transfer and breast milk, but may be particularly low in high-risk infants such as those born preterm. Maternally derived antibodies can now be supplemented by the administration of anti-RSV monoclonal antibodies, while a rising wave of maternal and paediatric vaccine strategies are approaching. The implementation of these prophylactics may profoundly decrease the healthcare burden of RSV. In this article, we review the role of antibody-mediated immunity in protecting children from RSV. We focus on maternally derived antibodies as the main source of protection against RSV and study factors that influence the scale of this transfer. The role of passive and active prophylactic approaches in protecting infants against RSV are discussed and knowledge gaps in our understanding of antibody-mediated protection against RSV are identified.

Innovative biomarkers TCN2 and LY6E can significantly inhibit respiratory syncytial virus infection

BACKGROUND

Respiratory syncytial virus (RSV) is a prominent etiological agent of lower respiratory tract infections in children, responsible for approximately 80% of cases of pediatric bronchiolitis and 50% of cases of infant pneumonia. Despite notable progress in the diagnosis and management of pediatric RSV infection, the current biomarkers for early-stage detection remain insufficient to meet clinical needs. Therefore, the development of more effective biomarkers for early-stage pediatric respiratory syncytial virus infection (EPR) is imperative.

METHODS

The datasets used in this study were derived from the Gene Expression Omnibus (GEO) database. We used GSE188427 dataset as the training set to screen for biomarkers. Biomarkers of EPR were screened by Weighted Gene Co-expression Network Analysis (WGCNA), three machine-learning algorithms (LASSO regression, Random Forest, XGBoost), and other comprehensive bioinformatics analysis techniques. To evaluate the diagnostic value of these biomarkers, multiple external and internal datasets were employed as validation sets. Next, an examination was performed to investigate the relationship between the screened biomarkers and the infiltration of immune cells. Furthermore, an investigation was carried out to identify potential small molecule compounds that interact with selected diagnostic markers. Finally, we confirmed that the expression levels of the selected biomarkers exhibited a significant increase following RSV infection, and they were further identified as having antiviral properties.

RESULTS

The study found that lymphocyte antigen 6E (LY6E) and Transcobalamin-2 (TCN2) are two biomarkers with diagnostic significance in EPR. Analysis of immune cell infiltration showed that they were associated with activation of multiple immune cells. Furthermore, our analysis demonstrated that small molecules, 3'-azido-3'-deoxythymine, methotrexate, and theophylline, have the potential to bind to TCN2 and exhibit antiviral properties. These compounds may serve as promising therapeutic agents for the management of pediatric RSV infections. Additionally, our data revealed an upregulation of LY6E and TCN2 expression in PBMCs from patients with RSV infection. ROC analysis indicated that LY6E and TCN2 possessed diagnostic value for RSV infection. Finally, we confirmed that LY6E and TCN2 expression increased after RSV infection and further inhibited RSV infection in A549 and BEAS-2B cell lines. Importantly, based on TCN2, our findings revealed the antiviral properties of a potentially efficacious compound, vitamin B12.

CONCLUSION

LY6E and TCN2 are potential peripheral blood diagnostic biomarkers for pediatric RSV infection. LY6E and TCN2 inhibit RSV infection, indicating that LY6E and TCN2 are potential therapeutic target for RSV infection.

Efficacy and safety of bivalent RSVpreF maternal vaccination to prevent RSV illness in Japanese infants: Subset analysis from the pivotal randomized phase 3 MATISSE trial

BACKGROUND

Maternal vaccination with respiratory syncytial virus prefusion F vaccine (RSVpreF) is effective at preventing RSV-associated lower respiratory tract illness (LRTI) in newborns/infants.

METHODS

This subgroup analysis from the global, phase 3, randomized, double-blind, placebo-controlled MATISSE (Maternal Immunization Study for Safety and Efficacy) trial evaluated participants enrolled in Japan. Pregnant women 24-36 weeks' gestation were randomized 1:1 to receive RSVpreF or placebo. Maternal safety endpoints included local reactions/systemic events within 7 days, adverse events (AEs) through 1 month, and serious AEs (SAEs) through 6 months after vaccination. In infants born to maternal participants, safety endpoints included specific birth outcomes, AEs through 1 month after birth, and SAEs and newly diagnosed chronic medical conditions through 12 or 24 months after birth. Vaccine efficacy in infants was assessed against RSV-positive, medically attended LRTI (RSV-MA-LRTI) and severe RSV-MA-LRTI through 180 days after birth.

RESULTS

In Japan, 230 maternal participants received RSVpreF and 232 received placebo; 218 and 216 infants born to these mothers, respectively, were analyzed. Observed vaccine efficacy (95 % CIs) against infant RSV-MA-LRTI within 90 and 180 days after birth was 100.0 % (30.9, 100.0; RSVpreF, 0 cases; placebo, 7 cases) and 87.6 % (7.2, 99.7; RSVpreF, 1 case; placebo, 8 cases), respectively. Vaccine efficacy (95 % CIs) against severe RSV-MA-LRTI within 90 and 180 days was 100.0 % (-140.9, 100.0; RSVpreF, 0 cases; placebo, 3 cases) and 75.1 % (-151.5, 99.5; RSVpreF, 1 case; placebo, 4 cases), respectively. No safety concerns were identified. AE rates ≤1 month after vaccination/birth were similar in the RSVpreF (maternal, 16.1 %; infant, 48.6 %) and placebo (19.8 %; 50.5 %) groups. Preterm birth rates were also similar (RSVpreF, 3.2 %; placebo, 6.0 %).

CONCLUSIONS

Safety and efficacy data in Japanese participants were consistent with overall MATISSE results, supporting the efficacy of maternal RSVpreF vaccination against severe MA-RSV-LRTI/MA-RSV-LRTI in infants, with no safety concerns. NCT04424316.

Viral Factors in Modulation of Host Immune Response: A Route to Novel Antiviral Agents and New Therapeutic Approaches

Viruses utilize host cells at all stages of their life cycle, from the transcription of genes and translation of viral proteins to the release of viral copies. The human immune system counteracts viruses through a variety of complex mechanisms, including both innate and adaptive components. Viruses have an ability to evade different components of the immune system and affect them, leading to disruption. This review covers contemporary knowledge about the virus-induced complex interplay of molecular interactions, including regulation of transcription and translation in host cells resulting in the modulation of immune system functions. Thorough investigation of molecular mechanisms and signaling pathways that are involved in modulating of host immune response to viral infections can help to develop novel approaches for antiviral therapy. In this review, we consider new therapeutic approaches for antiviral treatment. Modern therapeutic strategies for the treatment and cure of human immunodeficiency virus (HIV) are considered in detail because HIV is a unique example of a virus that leads to host T lymphocyte deregulation and significant modulation of the host immune response. Furthermore, peculiarities of some promising novel agents for the treatment of various viral infections are described.

Occurrence of Central Nervous System Complications of Respiratory Syncytial Virus Infections: A Systematic Review with Meta-Analysis

An increasing base of evidence suggests that respiratory syncytial virus (RSV) infections may be associated with neurological complications. In accord with the PRISMA statement, we performed a systematic review and meta-analysis on the occurrence of encephalitis and encephalopathy associated with documented RSV infections. PubMed, Embase, and Scopus databases were searched for eligible observational studies published up to 10 April 2024. Raw data included the occurrence of RSV infections among cases of encephalitis and/or encephalopathy and cases of encephalitis and/or encephalopathy among series of RSV infections. Data were pooled in a random effects model. Case reports were also collected, and their data pooled as a cumulative series. Heterogeneity was assessed using the I2 measure, while reporting bias was assessed by means of funnel plots and regression analysis. A total of 15 studies for a total of 7719 RSV infections and 1631 cases of encephalitis were analyzed. Moreover, 27 case reports and case series were retrieved, for a total of 84 individual cases of encephalitis/encephalopathy occurring during a documented RSV infection. A pooled prevalence of 2.20 cases of encephalitis/encephalopathy per 100 RSV cases (I2 = 99%) was calculated, while a prevalence of RSV infections among cases of encephalitis/encephalopathy was estimated to 3.53 per 100 cases for studies on respiratory specimens (I2 = 48%) and 0.37 per cases on central nervous system (CNS) specimens (I2 = 0%). Detection of RSV within the CNS was relatively rare (17.86% of pooled case reports), being associated with male gender (adjusted odds ratio [aOR] 5.021, 95% confidence interval [95%CI] 1.104 to 22.831) and recovery with long-term sequelae (aOR 5.699, 95%CI 1.152; 28.183). Case fatality ratio was estimated to be 0.43 per 100 cases on observational studies and 10.71% in case reports, a difference likely due to publication bias. In summary, RSV represented a not frequent but notable cause of encephalitis/encephalopathy in adults and children. The paucity of available studies not only recommends a cautious appraisal of our results but stresses the clinical significance of future studies on incident cases of encephalitis and/or encephalopathy.

Coinfection of viruses in children with community-acquired pneumonia

BACKGROUND

Virus, particularly respiratory tract virus infection is likely to co-occur in children with community-acquired pneumonia (CAP). Study focusing on the association between common viruses coinfection and children with CAP is rare. We aimed to study the association between seven common viruses coinfection and clinical/laboratory indexes in children with CAP.

METHODS

Six hundred and eighty-four CAP cases from our hospital were enrolled retrospectively. Seven common viruses, including influenza A (FluA), influenza B (FluB), human parainfluenza virus (HPIV), Esptein-Barr virus (EBV), coxsackie virus (CoxsV), cytomegalovirus (CMV), and herpes simplex virus (HSV) were investigated for their associations with CAP. We analyzed the differences of hospitalization days, white blood cell (WBC), c-reactive protein (CRP), platelet (PLT), erythrocyte sedimentation rate (ESR), procalcitonin (PCT), urine red blood cell (uRBC), blood urea nitrogen (BUN), serum creatinine (Scr), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and creatine kinase isoenzyme (CKMB) among different viruses coinfection groups by using one-way ANOVA analysis. The differences of clinical/laboratory indexes between ordinary and severe pneumonia groups, as well as non-virus vs multi co-infection viruses groups, and single vs multi co-infection viruses groups by using independent samples T test. Receiver operating characteristic (ROC) curve analyses were applied to test the the predictive value of the clinical/laboratory parameters for the risk of viruses coinfections among CAP. Binary logistic analysis was performed to test the association between various indexes and viruses co-infection.

RESULTS

Eighty-four multiple viruses coinfections yielded different prognosis compared with that in 220 single virus coinfection. CMV coinfection was associated with longest hospitalization days, highest ALT, AST and CKMB level. HSV coinfection was associated with highest WBC count, CRP, ESR, and BUN. EBV coinfection was associated with highest PLT and PCT level. FluB coinfection was associated with highest Scr level. CoxsV coinfection was associated with highest uRBC, LDH and CK level. ROC curve analyses showed that CK had the largest area under the curve (AUC: 0.672, p < 10-4) for the risk of viruses coinfections risk in CAP. Significant association between PLT, uRBC, BUN, CK, and CKMB and virus coinfection risk in CAP was observed.

CONCLUSIONS

Multiple viruses coinfections indicated different prognosis. Different viruses coinfection yielded varying degrees of effects on the cardiac, liver, kidney and inflamatory injury in CAP. The alterations of clinical/laboratory parameters, particularly CK may be associated with the risk of viruses coinfections in CAP.

The Multifaceted Burden of Respiratory Syncytial Virus (RSV) Infections in Young Children on the Family: A European Study

INTRODUCTION

Since the majority of hospitalisations due to RSV occur in young children, the illness profoundly influences the entire family. However, comprehensive evidence regarding its overall effects remains limited. The ResQ Family study aims to investigate the burden of RSV-induced pediatric hospitalisation on affected families.

METHODS

Spanning the 2022-2023 RSV season, an interdisciplinary, observational study was conducted in Germany, France, Italy and Sweden. Using an online questionnaire, parents and caregivers of children (< 24 months of age) with an RSV-induced hospitalisation were recruited. Information was gathered on topics related to RSV and parental health-related quality of life (HRQoL) during the acute infection phase (t0) and 6 weeks later (t1). Descriptive evaluations of the data set were performed during t0 and regarding a potential change over the observation period (t0 vs. t1). Subgroup analysis aimed to further identify differences across the countries.

RESULTS

A total set of 138 affected parents/caregivers were included in the study, with 59 participants responding to the follow-up survey (t1). Particularly during the acute infection phase, parental HRQoL was shown to be negatively influenced by the child's RSV infection [total score (p < 0.001, d = 0.54), parent HRQoL summary score (p < 0.001, d = 0.67) and family functioning summary score (p = 0.007, d = 0.33)]. Significant disparities in disease awareness and support structures were observed across Europe, with France and Sweden showing notably higher levels.

CONCLUSION

The ResQ Family study provides convincing evidence that RSV-associated hospitalisations in young children across Europe generate a multifaced burden for the entire family, partly even beyond the acute infection phase. Standardised approaches for disease prevention at societal, educational and policy levels are needed to guarantee every newborn the best possible start into life.

TRIAL REGISTRATION

ClinicalTrials.gov, identifier, NCT05550545.

Population Attributable Risk of Wheeze in 2-<6-Year-old Children, Following a Respiratory Syncytial Virus Lower Respiratory Tract Infection in The First 2 Years of Life

BACKGROUND

There is limited evidence regarding the proportion of wheeze in young children attributable to respiratory syncytial virus lower respiratory tract infections (RSV-LRTI) occurring early in life. This cohort study prospectively determined the population attributable risk (PAR) and risk percent (PAR%) of wheeze in 2-<6-year-old children previously surveilled in a primary study for RSV-LRTI from birth to their second birthday (RSV-LRTI<2Y).

METHODS

From 2013 to 2021, 2-year-old children from 8 countries were enrolled in this extension study (NCT01995175) and were followed through quarterly surveillance contacts until their sixth birthday for the occurrence of parent-reported wheeze, medically-attended wheeze or recurrent wheeze episodes (≥4 episodes/year). PAR% was calculated as PAR divided by the cumulative incidence of wheeze in all participants.

RESULTS

Of 1395 children included in the analyses, 126 had documented RSV-LRTI<2Y. Cumulative incidences were higher for reported (38.1% vs. 13.6%), medically-attended (30.2% vs. 11.8%) and recurrent wheeze outcomes (4.0% vs. 0.6%) in participants with RSV-LRTI<2Y than those without RSV-LRTI<2Y. The PARs for all episodes of reported, medically-attended and recurrent wheeze were 22.2, 16.6 and 3.1 per 1000 children, corresponding to PAR% of 14.1%, 12.3% and 35.9%. In univariate analyses, all 3 wheeze outcomes were strongly associated with RSV-LRTI<2Y (all global P < 0.01). Multivariable modeling for medically-attended wheeze showed a strong association with RSV-LRTI after adjustment for covariates (global P < 0.0001).

CONCLUSIONS

A substantial amount of wheeze from the second to sixth birthday is potentially attributable to RSV-LRTI<2Y. Prevention of RSV-LRTI<2Y could potentially reduce wheezing episodes in 2-<6-year-old children.

Cost-Effectiveness Analysis of Maternal Respiratory Syncytial Virus Vaccine in Protecting Infants from RSV Infection in Japan

INTRODUCTION

Respiratory syncytial virus (RSV) is one of the major causes of respiratory tract infections among children. Until recently, the monoclonal antibody palivizumab was the only RSV prophylaxis available in Japan. In 2024, the bivalent RSV prefusion F protein-based (RSVpreF) vaccine was approved for the prevention of RSV infection in infants by active immunization of pregnant women. In this study, we assessed the cost-effectiveness of a combined strategy of RSVpreF vaccine and palivizumab in Japanese setting.

METHODS

Using a Markov model, we evaluated prevented cases and deaths of medically attended RSV infections from birth to age 11 months for each of the three healthcare settings: inpatient (hospitalization), emergency department visits, and outpatient visits. Incremental cost-effectiveness ratios (ICERs) were calculated from economic outcomes (intervention costs, medication costs, and productivity losses) and quality-adjusted life years (QALYs). Further, we calculated the maximum price of RSVpreF vaccine within which the program would be cost-effective.

RESULTS

In comparison with the current prophylaxis (palivizumab alone), a combined prophylaxis of year-round RSVpreF vaccination of pregnant women and palivizumab prescription for premature infants born in < 32 weeks gestational age (wGA) and all infants with high risk prevented 14,382 medically attended cases of RSV (hospitalization, 7490 cases; emergency department, 2239 cases; outpatient, 4653 cases) and 7 deaths, respectively. From a healthcare payer perspective, when the price of RSVpreF vaccine was equal to or less than ¥23,948 (US $182), a combination prophylaxis was cost-effective under the ICER threshold of ¥5 million per QALY. The other combination prophylaxis of year-round RSVpreF vaccination and palivizumab prescription of premature born in < 32 wGA regardless of risk in infants was a dominant strategy (more effective and less costly).

CONCLUSION

A combined prophylaxis of year-round RSVpreF vaccine and palivizumab could be a cost-effective strategy to protect neonates throughout the infant stage (< 1 years old) in Japan.

First real-world data on universal respiratory syncytial virus prophylaxis with Nirsevimab in infants

Introduction

Respiratory Syncytial Virus (RSV) predominantly affects young children, with a peak incidence in temperate regions of the northern hemisphere from October to May. Children under 24 months of age are particularly vulnerable because of the immaturity of their lungs and immune systems, often leading to severe respiratory infections. The World Health Organization (WHO) recognizes RSV as a global health priority. Recently, Nirsevimab, a long-acting monoclonal antibody (mAb), was authorised to prevent RSV disease in infants.

Methods

Our narrative review brings together the effectiveness data of Nirsevimab available in the literature, highlighting the strengths and weaknesses of the published studies and the prevention opportunities represented by the new preparation.

Results

All reviewed studies provide evidence for the effectiveness of immunisation with Nirsevimab in real-world settings, beyond the controlled conditions of clinical trials, and highlight its safety and feasibility. Nirsevimab significantly reduces RSV hospitalisations and Intensive Care Unit (ICU) admissions. High coverage and high efficacy of immunisation have been reported, although supply issues and variability in studies present challenges.

Conclusions

Continued research and surveillance are critical to understanding the long-term effectiveness of Nirsevimab. Overall, available data provide valuable insights into the efficacy, safety, and impact of immunisation with Nirsevimab in preventing severe RSV infections in infants, highlighting its potential to reduce the burden of RSV-related hospitalisations and improve paediatric health outcomes.

Evolving Epidemiology of Pediatric Respiratory Syncytial Virus (RSV) Cases Around COVID-19 Pandemic: Impact and Clinical Insights, Retrospective Cohort Study

BACKGROUND

The burden of respiratory syncytial virus (RSV) in high-risk pediatric patients remains unclear. Therefore, this study aims to characterize pediatric RSV cases from January 2019 to December 2022 and assess the impact of the COVID-19 pandemic on RSV burden and RSV-related outcomes. In addition, examining factors influencing RSV-related hospitalization.

METHODS

This is a retrospective study that included pediatric patients (aged 14 and below) who presented at King Faisal Specialist Hospital and Research Centre (KFSHRC) in Riyadh, Saudi Arabia with RSV infection identified using real-time reverse-transcriptase polymerase chain reaction assays. Statistical analyses were performed using STATA.

RESULTS

A total of 885 RSV cases were reported; (56.05%) were males and (43.95%) were females with a median age of 24 months [interquartile range (IQR): 11-60]. 534 (60.34%) required hospitalization. As for RSV seasonality, there was a significant increase in RSV prevalence following the COVID-19 pandemic, escalating from 205 cases in 2019 to 425 cases in 2022. The increase in 2022 was evident in January and persisted from September to December, reaching its peak during the months of October (20.70% - 88 cases) and November (32.00% - 136 cases). About (27.12%) of RSV infected children were medically free patients. Symptomatic patients exhibited various clinical manifestations, with ventilation necessary in (13.11%) of cases. Further analysis revealed significant changes in RSV-related outcomes post-COVID-19, including a decrease in hospitalization rates, an increase in medically free patients, and a lower need for ventilation (p < 0.05). Notably, a significant proportion of RSV admissions occurred within the first 6 months of life, with (77.69%) in the age group of 0 to 5 months. In addition, previous RSV infection, prematurity, low birth weight, renal disease, congenital heart disease, endocrine/metabolic disease, neuro/neuromuscular diseases, and genetic disorders were positively associated with hospitalization (P < 0.05). Interestingly, asthma and bone marrow transplantation were negatively associated with hospitalization (P < 0.05). The mortality rate in this study is (2.37%) (21/885).

CONCLUSION

This study provides a comprehensive understanding of the demographic and clinical factors influencing RSV outcomes, highlighting the impact of the COVID-19 pandemic and shedding light on potential risk factors for RSV-related hospitalization. The highest prevalence of RSV during (September to January), aligning with global patterns and emphasizing the importance of timing in preventive strategies.

Trend of accesses to the Emergency Department of a Teaching Hospital of Tuscany due to bronchiolitis in 2018-2023: new challenges

Introduction

Acute bronchiolitis is one of leading causes of lower respiratory tract infection and hospitalisation in children less than one year old worldwide. The aim of our study is investigating the impact of bronchiolitis in children paediatric to the Emergency Department (ED) of Teaching Hospital (AOUS), Santa Maria alle Scotte of Siena, Tuscany (Italy).

Methods

A retrospective observational study was conducted on the accesses performed at the ED of the AOUS of Siena by children under 18 years of age suffering from bronchiolitis from September 2018 to April 2023.

Results

There were 36,031 patients between 0 and 18 years old in the Emergency Department, 383 of which presented bronchiolitis (age 4.8 months C.I.:3.5-6 months.; 54% male). Those who accessed the ED with a higher priority code were more likely to be subsequently admitted (O.R.:2.6; C.I.:1.3-5.1; p < 0.01). Those who accessed the ED with symptoms of bronchiolitis during the weekend were less likely to have been sent from community medicine services or professionals (O.R:0.1; C.I:0.0-0.5; p < 0.001). Children below 1 year old were more likely to access the ED with respiratory distress symptoms (O.R.:2.6; C.I.:1.5-4.3; p < 0.001). Finally, those who accessed the ED with bronchiolitis were more likely to be admitted than those who accessed for other conditions (O.R:24.5; C.I.:19.4-31; p < 0.001).

Conclusions

It is necessary to invest protocols integrating hospital services and community medicine in order to achieve a timely diagnosis and to reduce the accesses to the ED of children presenting mild, non-severe form of bronchiolitis in order to avoid the overload of hospital services.

Inhalation of 2, 4-di-tert-butylphenol-Loaded micelles suppresses respiratory syncytial virus infection in mice

Human respiratory syncytial virus (RSV) is a common cause of respiratory infections in infants, young children, and elderly people. However, there are no effective treatments or vaccines available in most countries. In this study, we explored the anti-RSV potential of 2, 4-Di-tert-butylphenol (2, 4-DTBP), a compound derived from Houttuynia cordata Thunb. To overcome the poor solubility of 2, 4-DTBP, we encapsulated it in polymeric micelles and delivered it by inhalation. We found that 2, 4-DTBP-loaded micelles inhibited RSV infection in vitro and improved survival, lung pathology, and viral clearance in RSV-infected mice. Our results suggested that 2, 4-DTBP-loaded micelle is a promising novel therapeutic agent for RSV infection.

Timing patterns of initial respiratory syncytial virus infection and factors influencing disease severity in hospitalized infants with different health status

This study aimed to determine the timing patterns of the initial respiratory syncytial virus (RSV) infection and to identify the factors influencing disease severity in infants of varying health status. A retrospective study was conducted at the Affiliated Children's Hospital of Chongqing Medical University from 2012 to 2022. The timing of the first RSV infection was estimated in infants with differing health status using correlation analysis, considering their birth time. Logistic regression was utilized to identify factors influencing severe RSV infection in these infants. RSV detection primarily occurred in the winter and spring. Epidemic season and peak timing of RSV were not significantly affected by health status or the COVID-19 pandemic. A strong positive correlation was observed between the age at RSV infection and the interval from birth to the RSV peak season. Infants born during the RSV epidemic season exhibited a higher likelihood of infection within the first 2 months postbirth. In contrast, those born outside the RSV epidemic season were more susceptible to infection during the subsequent peak. Notably, infants with pre-existing health conditions contracted RSV at an earlier age compared to their healthy counterparts. Among healthy infants, severe RSV infection was associated with sex, age, and timing of infection. For infants with underlying conditions, severe RSV infection was primarily related to age and timing of infection. The initial timing of RSV infection in infants varied depending on their health status. Young age and infection timing during the RSV epidemic season were significant risk factors for severe RSV infection. These findings provide a theoretical basis for optimizing immunization strategies for infants with diverse health conditions.

Cost-effectiveness Analysis of Maternal Immunization with RSVpreF Vaccine for the Prevention of Respiratory Syncytial Virus Among Infants in Spain

INTRODUCTION

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory infections (ALRI) in children under one year of age. In high-income countries, RSV infections cause a significant overload of care every winter, imposing a significant burden to the healthcare system, which has made the development of prevention strategies a major global health priority. In this context, a new bivalent RSV prefusion F protein-based vaccine (RSVpreF) has recently been approved. The objective of this study was to evaluate the cost-effectiveness of vaccinating pregnant women with the RSVpreF vaccine to prevent RSV in infants from the Spanish National Healthcare System (NHS) perspective.

METHODS

A hypothetical cohort framework and a Markov-type process were used to estimate clinical outcomes, costs, quality-adjusted life years (QALY) and cost-per-QALY gained (willingness-to-pay threshold: €25,000/QALY) for newborn infants born to RSV-vaccinated versus unvaccinated mothers over an RSV season. The base case analysis was performed from the NHS perspective including direct costs (€2023) and applying a discount of 3% to future costs and outcomes. To evaluate the robustness of the model, several scenarios, and deterministic and probabilistic analyses were carried out. All the parameters and assumptions were validated by a panel of experts.

RESULTS

The results of the study showed that year-round maternal vaccination program with 70% coverage is a dominant option compared to no intervention, resulting in direct cost savings of €1.8 million each year, with an increase of 551 QALYs. Maternal vaccination could prevent 38% of hospital admissions, 23% of emergency room visits, 19% of primary care visits, and 34% of deaths due to RSV. All scenario analyses showed consistent results, and according to the probabilistic sensitivity analysis (PSA), the probability of maternal vaccination being cost-effective versus no intervention was 99%.

CONCLUSIONS

From the Spanish NHS perspective, maternal vaccination with bivalent RSVpreF is a dominant alternative compared with a non-prevention strategy.

Acceptance of New Respiratory Syncytial Virus Vaccine among Pregnant Women in Nepal for Future Routine Immunization: A Descriptive Crosssectional Study

INTRODUCTION

Children are at greatest risk for severe illness from Respiratory Syncytial Virus (RSV). The aim of the study was to find out the knowledge of RSV, practice and knowledge about vaccination during pregnancy and the willingness to accept vaccines against RSV during pregnancy in the future among mothers needs to be understood which would add up information for stakeholder and policy makers.

METHODS

A preformed Performa was used for face-to-face interview was conducted among 340 pregnant women who visited the Antenatal clinic from 15-Oct-2023 to 30-Nov-2023 in their second and third trimester. Socio-demographic characteristics, knowledge and the attitude concerning antenatal vaccination affecting the acceptance of RSV vaccine were evaluated from the interview.

RESULTS

The mean age was 28.4 years, with 310 (91.18%) already having at least one child. Six (1.76%) participants had previously heard about RSV, and 325 (95.59%) were aware of the problem caused by RSV after they were briefly explained about it in their local language. A total of 246 (72.35%) of the mothers expressed willingness to be vaccinated themselves rather than vaccinating their children if such an option existed. Only 2 (0.59%) participants were familiar with nasal vaccines, and only 18 (5.29%) believed in such vaccines being effective. Despite this, almost all participants 339 (99.71%) in the study demonstrated willingness to receive additional antenatal vaccines if approved for use in future.

CONCLUSIONS

The study showed a limited understanding of RSV in children among pregnant women in Nepal. However, they are aware of the impact of bronchiolitis and expressed a strong willingness to undergo maternal vaccination against RSV.

Modelling respiratory syncytial virus age-specific risk of hospitalisation in term and preterm infants

BACKGROUND

Respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory infections in children worldwide. The highest incidence of severe disease is in the first 6 months of life, with infants born preterm at greatest risk for severe RSV infections. The licensure of new RSV therapeutics (a long-acting monoclonal antibody and a maternal vaccine) in Europe, USA, UK and most recently in Australia, has driven the need for strategic decision making on the implementation of RSV immunisation programs. Data driven approaches, considering the local RSV epidemiology, are critical to advise on the optimal use of these therapeutics for effective RSV control.

METHODS

We developed a dynamic compartmental model of RSV transmission fitted to individually-linked population-based laboratory, perinatal and hospitalisation data for 2000-2012 from metropolitan Western Australia (WA), stratified by age and prior exposure. We account for the differential risk of RSV-hospitalisation in full-term and preterm infants (defined as < 37 weeks gestation). We formulated a function relating age, RSV exposure history, and preterm status to the risk of RSV-hospitalisation given infection.

RESULTS

The age-to-risk function shows that risk of hospitalisation, given RSV infection, declines quickly in the first 12 months of life for all infants and is 2.6 times higher in preterm compared with term infants. The hospitalisation risk, given infection, declines to < 10% of the risk at birth by age 7 months for term infants and by 9 months for preterm infants.

CONCLUSIONS

The dynamic model, using the age-to-risk function, characterises RSV epidemiology for metropolitan WA and can now be extended to predict the impact of prevention measures. The stratification of the model by preterm status will enable the comparative assessment of potential strategies in the extended model that target this RSV risk group relative to all-population approaches. Furthermore, the age-to-risk function developed in this work has wider relevance to the epidemiological characterisation of RSV.

Safety and Efficacy of Nirsevimab in a Universal Prevention Program of Respiratory Syncytial Virus Bronchiolitis in Newborns and Infants in the First Year of Life in the Valle d'Aosta Region, Italy, in the 2023-2024 Epidemic Season

Respiratory syncytial virus (RSV) bronchiolitis remains a significant global health burden, particularly in newborns and infants during their first year of life. The quest for an effective preventive strategy against RSV has long been sought, and recent developments have shown promise in the form of nirsevimab, a monoclonal antibody specifically designed for RSV prophylaxis. Valle d'Aosta was the first Italian region to propose universal prophylaxis with nirsevimab for newborns and infants in their first epidemic season as early as 2023-2024. This study describes the effectiveness and safety of the universal prevention program of RSV bronchiolitis using the monoclonal antibody nirsevimab in children resident in Valle d'Aosta born during the 2023-2024 epidemic season. There were 556 neonates born from 1 May 2023 to 15 February 2024. The risk of hospitalization for RSV bronchiolitis in 2023-2024 was 3.2%, compared to 7% in the 2022-2023 epidemic season (p < 0.001). After the start of the prophylaxis campaign with nirsevimab, the risk of hospitalization was 8.3% in the sample of infants who did not adhere to the prophylaxis, while no child in the sample of those treated (p < 0.001) was hospitalized for bronchiolitis. Few mild transient side effects were reported. This study shows the efficacy and safety of universal prophylaxis with nirsevimab in neonates, making Valle d'Aosta the first Italian region to offer universal prophylaxis to newborns without risk factors for RSV complications. Future research could further explore its long-term impact and cost-effectiveness.

Birth characteristics as predictors of respiratory syncytial virus hospitalisation in newborns to optimise immunisation schedule

AIM

To examine birth characteristics that influence infant respiratory syncytial virus (RSV) hospitalisation risk in order to identify risk factors for severe RSV infections.

METHODS

Retrospective cohort study of 460 771 Sicilian children under 6 months old from January 2007 to December 2017. Hospital discharge records were consulted to identify cases and hospitalisations with International Classification of Diseases, Ninth Revision, Clinical Modification codes 466.11 (RSV bronchiolitis), 480.1 (RSV pneumonia) and 079.6 (RSV). RSV hospitalisation risk was estimated using adjusted odds ratios (aOR) and 95% confidence intervals (95% CI).

RESULTS

Overall, 2420 (5.25 per 1000 infants) RSV-related hospitalisations were identified during the study, with girls accounting for 52.8%. RSV hospitalisation risk increased for full-term, transferred, extreme immature, and preterm neonates with serious issues (aOR 3.25, 95% CI 2.90-3.64; aOR 1.86, 95% CI 1.47-2.32; aOR 1.54, 95% CI 1.11-2.07; and aOR 1.48, 95% CI 1.14-1.90). Compared to children born in June, the risk of RSV hospitalisation was significantly higher in children born in January (aOR 28.09, 95% CI 17.68-48.24) and December (aOR 27.36, 95% CI 17.21-46.99).

CONCLUSION

This study identified birth month and diagnosis-related groups as key predictors of RSV hospitalisations. This could help manage monoclonal antibody appropriateness criteria.

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.

Respiratory Syncytial Virus Infections in Recipients of Bone Marrow Transplants: A Systematic Review and Meta-Analysis

Human Respiratory Syncytial Virus (RSV) is a common cause of respiratory tract infections. Usually associated with infants and children, an increasing amount of evidence suggests that RSV can cause substantial morbidity and mortality in immunocompromised individuals, including recipients of bone marrow transplantation (BMT). The present systematic review was therefore designed in accordance with the PRISMA guidelines to collect available evidence about RSV infections in BMT recipients. Three medical databases (PubMed, Embase, and MedRxiv) were therefore searched for eligible observational studies published up to 30 September 2023 and collected cases were pooled in a random-effects model. Heterogeneity was assessed using I2 statistics. Reporting bias was assessed by means of funnel plots and regression analysis. Overall, 30 studies were retrieved, including 20,067 BMT cases and 821 RSV infection episodes. Of them, 351 were lower respiratory tract infections, and a total of 78 RSV-related deaths were collected. A pooled attack rate of 5.40% (95% confidence interval [95%CI] 3.81 to 7.60) was identified, with a corresponding incidence rate of 14.77 cases per 1000 person-years (95%CI 9.43 to 20.11), and a case fatality ratio (CFR) of 7.28% (95%CI 4.94 to 10.60). Attack rates were higher in adults (8.49%, 95%CI 5.16 to 13.67) than in children (4.79%, 95%CI 3.05 to 7.45), with similar CFR (5.99%, 95%CI 2.31 to 14.63 vs. 5.85%, 95%CI 3.35 to 10.02). By assuming RSV attack rates as a reference group, influenza (RR 0.518; 95%CI 0.446 to 0.601), adenovirus (RR 0.679, 95%CI 0.553 to 0.830), and human metapneumovirus (RR 0.536, 95%CI 0.438 to 0.655) were associated with a substantially reduced risk for developing corresponding respiratory infection. Despite the heterogeneous settings and the uneven proportion of adult and pediatric cases, our study has identified high attack rates and a substantial CFR of RSV in recipients of BMT, stressing the importance of specifically tailored preventive strategies and the need for effective treatment options.

RSV Prefusion F Protein-Based Maternal Vaccine - Preterm Birth and Other Outcomes

BACKGROUND

Vaccination against respiratory syncytial virus (RSV) during pregnancy may protect infants from RSV disease. Efficacy and safety data on a candidate RSV prefusion F protein-based maternal vaccine (RSVPreF3-Mat) are needed.

METHODS

We conducted a phase 3 trial involving pregnant women 18 to 49 years of age to assess the efficacy and safety of RSVPreF3-Mat. The women were randomly assigned in a 2:1 ratio to receive RSVPreF3-Mat or placebo between 24 weeks 0 days and 34 weeks 0 days of gestation. The primary outcomes were any or severe medically assessed RSV-associated lower respiratory tract disease in infants from birth to 6 months of age and safety in infants from birth to 12 months of age. After the observation of a higher risk of preterm birth in the vaccine group than in the placebo group, enrollment and vaccination were stopped early, and exploratory analyses of the safety signal of preterm birth were performed.

RESULTS

The analyses included 5328 pregnant women and 5233 infants; the target enrollment of approximately 10,000 pregnant women and their infants was not reached because enrollment was stopped early. A total of 3426 infants in the vaccine group and 1711 infants in the placebo group were followed from birth to 6 months of age; 16 and 24 infants, respectively, had any medically assessed RSV-associated lower respiratory tract disease (vaccine efficacy, 65.5%; 95% credible interval, 37.5 to 82.0), and 8 and 14, respectively, had severe medically assessed RSV-associated lower respiratory tract disease (vaccine efficacy, 69.0%; 95% credible interval, 33.0 to 87.6). Preterm birth occurred in 6.8% of the infants (237 of 3494) in the vaccine group and in 4.9% of those (86 of 1739) in the placebo group (relative risk, 1.37; 95% confidence interval [CI], 1.08 to 1.74; P = 0.01); neonatal death occurred in 0.4% (13 of 3494) and 0.2% (3 of 1739), respectively (relative risk, 2.16; 95% CI, 0.62 to 7.56; P = 0.23), an imbalance probably attributable to the greater percentage of preterm births in the vaccine group. No other safety signal was observed.

CONCLUSIONS

The results of this trial, in which enrollment was stopped early because of safety concerns, suggest that the risks of any and severe medically assessed RSV-associated lower respiratory tract disease among infants were lower with the candidate maternal RSV vaccine than with placebo but that the risk of preterm birth was higher with the candidate vaccine. (Funded by GlaxoSmithKline Biologicals; ClinicalTrials.gov number, NCT04605159.).

Respiratory syncytial virus-associated hospitalizations among children: an Italian retrospective observational study

BACKGROUND

Respiratory syncytial virus (RSV), a single-stranded RNA virus, is a leading cause of hospitalization in infants, especially ≤ 2 months of life. In the light new immunization strategies adoption, we described epidemiological and clinical characteristics of RSV-associated hospitalizations in pediatric and neonatal intensive care units of the Policlinico Foggia Hospital, Apulia Region, Italy.

METHODS

Hospitalized children with a laboratory-confirmed RSV infection from 2011 to 2023 were retrospectively evaluated. Clinical information was collected from Hospital Discharge Registry in the period 2011-2020. The proportion of the hospitalization for acute respiratory infections (ARIs) associated to RSV was calculated and the hospitalization cost was analyzed by using the diagnosis-related group reimbursement rate. The anticipated impact of immunization either with monoclonal antibodies or maternal immunization on the number of hospitalizations was estimated. All analyses and quality assessment were performed using STATA/SE15.0.

RESULTS

A total of 1,005 RSV-cases were included in the study, of which 86.3% occurred between December-March. In the period 2011-2020, 832 RSV-cases were matched with the corresponding hospital admissions; 75.2% were aged < 1 year (49.6% 0-2 months). Bronchiolitis was the most frequent admission diagnosis occurring in 63.3% of patients; 25% of children were affected by a very severe RSV-disease. Younger age ≤ 2 months (OR:14.8, 95%CI:8.30-26.31, p = 0.000), higher length-of-hospital-stay (OR:1.01, 95%CI:1.0-1.02, p = 0.030) and history of prematurity (OR:4.4, 95%CI:1.57-12.11, p = 0.005) were associated with a higher disease severity. RSV caused 48.9% of ARIs among children < 1 year. The mean cost of an RSV-associated hospitalization was 3,036 euros/year, with the higher cost in the 0-2 months age group (4,225 euros/year). Immunization programs with nirsevimab could prevent 51.4 RSV hospitalizations/year and 18.1 very severe RSV disease/year in infants < 1 year of age. RSV vaccine could prevent 46.1 of hospitalizations/year caused by RSV within 180 days after birth.

CONCLUSIONS

Our study contributes to outlining the baseline profile of RSV-associated hospitalizations among Italian children by providing epidemiological/clinical/economic estimates. While awaiting new recommendations on immunization, healthcare-workers should persist in implementing public health measures and appropriate case management to control RSV seasonal epidemics. Strengthened laboratory RSV surveillance is needed to inform the implementation of the new immunization strategies.

Addressing global health disparities in the management of RSV infection in infants and children: Strategies for preventing bronchiolitis and post-bronchiolitis recurrent wheezing

Background: The topic of equitable access to health care and its impact on exacerbating worldwide inequities in child health not only strikes at the heart of our health-care delivery systems but also deeply resonates with our collective social consciences. Nowhere is this better seen on a global scale than in the burden of illness caused by respiratory syncytial virus (RSV) infection, which extracts the most severe morbidity and mortality in infants and children in low- and middle-income countries (LMIC). This report addresses global health disparities that exist in the management of RSV infection in infants and children, and offers strategies for preventing bronchiolitis and postbronchiolitis recurrent wheezing in LMICs. Methods: A systematic literature review was conducted across the PubMed data bases of RSV infection and the socioeconomic impact of bronchiolitis and postbronchiolitis recurrent wheezing in LMICs. Results: The results of the present study address the many issues that deal with the question if prevention of RSV bronchiolitis can mitigate recurrent wheezing episodes and links RSV risks, downstream effects, prevention, malnutrition, and socioeconomic restraints of developing countries with a call for possible global action. Conclusion: The present study stresses the importance of considering the linkage between malnutrition and disease susceptibility because of the known relationships between undernutrition and greater vulnerability to infectious diseases, including RSV infection. These complex interactions between infectious disease and undernutrition also raise issues on the longer-term sequelae of postbronchiolitis recurrent wheezing. This prompts a discussion on whether industrialized countries should prioritize the provision of newly developed monoclonal antibodies and RSV vaccines to LMICs or whether vital nutritional needs should be a first focus. The resolution of these issues will require research and greater international discourse.

Cost-effectiveness of nirsevimab and palivizumab for respiratory syncytial virus prophylaxis in preterm infants 29-34 6/7 weeks' gestation in the United States

BACKGROUND

Respiratory syncytial virus (RSV) hospitalizations have increased since the 2014 guideline update recommended against the use of palivizumab for preterm infants born ≥29 0/7 weeks' gestational age (GA) without additional risk factors. A novel drug candidate, nirsevimab, has been developed for this population. We analyzed the cost-effectiveness of palivizumab/nirsevimab vs. no prophylaxis in this population.

METHODS

A hybrid-Markov model predicted the RSV clinical course in the first year of life and sequelae in the subsequent four years for preterm infants from the healthcare and societal perspectives. Model parameters were derived from the literature. We calculated costs and quality-adjusted life-years (QALYs) to produce an incremental cost-effectiveness ratio (ICER) evaluated at a willingness-to-pay threshold of $150,000/QALY. Sensitivity analyses assessed model robustness. A threshold analysis examined nirsevimab pricing uncertainty.

RESULTS

Compared to no prophylaxis, palivizumab costs $9572 and $9584 more from the healthcare and societal perspectives, respectively, with 0.0019 QALYs gained per patient over five years, resulting in ICERs >$5 million per QALY from each perspective. Results were robust to parameter uncertainties; probabilistic sensitivity analysis revealed that no prophylaxis had a 100% probability of being cost-effective. The threshold analysis suggested that nirsevimab is not cost-effective when compared to no prophylaxis if the price exceeds $1962 from a societal perspective.

CONCLUSION

Palivizumab is dominated by no prophylaxis for preterm infants 29 0/7-34 6/7 weeks' GA with no additional risk factors. Relevant stakeholders should consider alternatives to palivizumab for this population that are both effective and economical.

Inpatient Rsv-Management 2016-2022: Epidemiology and Adherence to A Bronchiolitis Treatment Standard at a German University Children's Hospital

BACKGROUND

This study analyzes the RSV season 2021/2022 in a referral children's hospital, compares the epidemiology and illness severity with RSV-infected inpatients from 2016 to 2020 and audits the adherence to our internal therapy standard for RSV bronchiolitis.

MATERIAL AND METHODS

Inpatients with rtPCR-confirmed RSV infection (Jan. 2016 to Jan. 2022).

RESULTS

The audit comprises 306 RSV inpatients, on average 50 hospitalizations per year; in 03/2020, a rapid RSV Season-Offset was observed. In the winter season 2020/2021, no patient with RSV was hospitalized. Beginning in July, we noticed a rapid increase of RSV-admissions (most cases in Sept./Oct, duration until Dec. 2021; n=53). In 2021-2022, a significant larger share needed PICU admission (9.4% vs 3.2%, p=0.040). Adherence to the internal guidance was low; only 11.8% (n=36) of all patients received supportive treatment without inhalative or systemic medications, 37% of all patients received antibiotics.

CONCLUSIONS

This audit confirms the strong impact of public preventive measures directed against SARS-CoV-2 transmission on RSV epidemiology. Few weeks after easing public COVID-19 restrictions (summer 2021), RSV inpatient cases rapidly increased, lasting until Dec. 2021. The audit of bronchiolitis management revealed surprisingly low adherence to the internal guidance, despite a face-to-face educational session with the attending pediatricians in Oct. 2021. Low adherence resulted in an unnecessary exposure of RSV patients to systemic medications of questionable benefit including antibiotics.

Characterisation of RSV infections in children without chronic diseases aged 0-36 months during the post-COVID-19 winter season 2022/2023

Background

Respiratory syncytial virus (RSV) is one of the leading causes of hospitalisation, morbidity, and mortality due to respiratory infection in the first years of life. This longitudinal prospective study outlines the 2022/23 season's viral patterns in Austria after the epidemiological changes determined by public health measures. We aimed to highlight differences within the RSV subtypes and genotypes in 0-36-month-old children without chronic diseases in the outpatient setting.

Methods

From November 2022 to March 2023 children younger than 36 months admitted to Vienna's largest paediatric primary healthcare centre with an acute respiratory infection were enrolled in this study. Nasal swabs and multiplex PCR panels detected 20 viruses including RSV subtypes and genotypes. Clinical presentation, features, and treatment of the participants were documented and analysed using the Modified Tal Score (MTS). Patients were scheduled for a telemedical follow-up one week after the initial appointment. Analysis was done using descriptive statistics, including Cramér V and binominal logarithmic regression.

Results

Among the 345 samples from 329 children, RSV was the most common virus (31.9%), followed by influenza (17.5%) and rhinovirus infections (20.58%). Of the RSV positive samples, only 13 cases were RSV subtype A (11.8%), whereas 97 were of subtype B (87.3%); ON1 and BA9 were the only detectable RSV genotypes (ON1: BA9 = 1:9.25). RSV was the main predictor of hospitalisation (OR: 7.5, 95% CI: (1.46-38.40), and age had a significant but smaller effect (OR: 0.89, 95% CI: (0.81-0.99). Almost all patients' clinical status improved within the first days.

Conclusion

RSV cases showed a rapid onset in late November 2022, and subtype B was predominant throughout the season. RSV infection was associated with higher hospitalisation rates, even after excluding high-risk patients (preterm and severe chronic diseases population).Further testing in the upcoming winter seasons will improve our knowledge of the dominant subtype and its association with disease severity, especially with the development of novel RSV vaccine candidates.

Changes in clinical, demographic, and outcome patterns of children hospitalized with non-SARS-CoV-2 viral low respiratory tract infections before and during the COVID pandemic in Rome, Italy

INTRODUCTION

We performed this study aiming to evaluate changes in epidemiology, clinical presentation and outcomes of children hospitalized for viral lower respiratory tract infections (LRTI).

METHODS

We performed a retrospective study of children younger than 18 years of age hospitalized for LRTIs with a positive respiratory viral testing from 2018 to 2022. We compared need of pediatric intensive care unit (PICU), invasive ventilation, and other respiratory support, viral etiologies, clinical presentations, imaging, and laboratory results in the precovid (2018-2019) and covid (2020-2022) period.

RESULTS

A total of 523 were included in the analysis. In the pandemic period, the detection of influenza was 95% less likely to occur (odds ratio [OR]: 0.05; 95% confidence interval [95% CI]: 0.02-0.12; p < .001), likewise the detection of adenovirus was 77% less likely to occur (OR: 0.23; 95% CI: 0.10-0.51; p < .001). In the pandemic period, the number of codetections increased from 15.52% in 2018 to 57.25% in 2022, resulting in a significantly increasing trend (p < .001). The odds of transfer to PICU was more than five times greater during the pandemic period (OR: 5.31; 95% CI: 1.78-15.86; p = .003).

CONCLUSIONS

We found that the pattern of LRTI in children during COVID-19 pandemic significantly changed in terms of etiologies and increased severity.

A molecular perspective for the development of antibodies against the human respiratory syncytial virus

The human respiratory syncytial virus (hRSV) is the leading etiologic agent causing respiratory infections in infants, children, older adults, and patients with comorbidities. Sixty-seven years have passed since the discovery of hRSV, and only a few successful mitigation or treatment tools have been developed against this virus. One of these is immunotherapy with monoclonal antibodies against structural proteins of the virus, such as Palivizumab, the first prophylactic approach approved by the Food and Drug Administration (FDA) of the USA. In this article, we discuss different strategies for the prevention and treatment of hRSV infection, focusing on the molecular mechanisms against each target that underly the rational design of antibodies against hRSV. At the same time, we describe the latest results regarding currently approved therapies against hRSV and the challenges associated with developing new candidates.

Respiratory Syncytial Virus, Influenza and SARS-CoV-2 in Homeless People from Urban Shelters: A Systematic Review and Meta-Analysis (2023)

Homeless people (HP) are disproportionally affected by respiratory disorders, including pneumococcal and mycobacterial infections. On the contrary, more limited evidence has been previously gathered on influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and very little is known about the occurrence of human respiratory syncytial virus (RSV), a common cause of respiratory tract infections among children and the elderly. The present systematic review was designed to collect available evidence about RSV, influenza and SARS-CoV-2 infections in HP, focusing on those from urban homeless shelters. Three medical databases (PubMed, Embase and Scopus) and the preprint repository medRxiv.org were therefore searched for eligible observational studies published up to 30 December 2023, and the collected cases were pooled in a random-effects model. Heterogeneity was assessed using the I2 statistics. Reporting bias was assessed by funnel plots and a regression analysis. Overall, 31 studies were retrieved, and of them, 17 reported on the point prevalence of respiratory pathogens, with pooled estimates of 4.91 cases per 1000 HP (95%CI: 2.46 to 9.80) for RSV, 3.47 per 1000 HP for influenza and 40.21 cases per 1000 HP (95%CI: 14.66 to 105.55) for SARS-CoV-2. Incidence estimates were calculated from 12 studies, and SARS-CoV-2 was characterized by the highest occurrence (9.58 diagnoses per 1000 persons-months, 95%CI: 3.00 to 16.16), followed by influenza (6.07, 95%CI: 0.00 to 15.06) and RSV (1.71, 95%CI: 0.00 to 4.13). Only four studies reported on the outcome of viral infections in HP: the assessed pathogens were associated with a high likelihood of hospitalization, while high rates of recurrence and eventual deaths were reported in cases of RSV infections. In summary, RSV, influenza and SARS-CoV-2 infections were documented in HP from urban shelters, and their potential outcomes stress the importance of specifically tailored preventive strategies.

All Eyes on the Prefusion-Stabilized F Construct, but Are We Missing the Potential of Alternative Targets for Respiratory Syncytial Virus Vaccine Design?

Respiratory Syncytial Virus (RSV) poses a significant global health concern as a major cause of lower respiratory tract infections (LRTIs). Over the last few years, substantial efforts have been directed towards developing vaccines and therapeutics to combat RSV, leading to a diverse landscape of vaccine candidates. Notably, two vaccines targeting the elderly and the first maternal vaccine have recently been approved. The majority of the vaccines and vaccine candidates rely solely on a prefusion-stabilized conformation known for its highly neutralizing epitopes. Although, so far, this antigen design appears to be successful for the elderly, our current understanding remains incomplete, requiring further improvement and refinement in this field. Pediatric vaccines still have a long journey ahead, and we must ensure that vaccines currently entering the market do not lose efficacy due to the emergence of mutations in RSV's circulating strains. This review will provide an overview of the current status of vaccine designs and what to focus on in the future. Further research into antigen design is essential, including the exploration of the potential of alternative RSV proteins to address these challenges and pave the way for the development of novel and effective vaccines, especially in the pediatric population.

Modeling the optimal seasonal monoclonal antibody administration strategy for respiratory syncytial virus (RSV) prevention based on age-season specific hospitalization rate of RSV in Suzhou, China, 2016-2022

BACKGROUND

The approval of nirsevimab brings light to reducing the heavy disease burden caused by respiratory syncytial virus (RSV). Considering the seasonality of RSV, the timing of administrating monoclonal antibody (mAb) is critical to maximize health utility. This study aimed to model and seek the optimal seasonal mAb administration strategy for preventing RSV-associated hospitalization.

METHODS

Age-season specific hospitalization rates for RSV-associated acute lower respiratory infection (RSV-ALRI) were estimated from a hospital-based birth cohort. Using these rates, we simulated and evaluated the effect of diverse mAb administration strategies on preventing RSV-ALRI hospitalization. Optimal strategies were selected based on their effectiveness and relative cost-effectiveness.

RESULTS

Compared with the year-round strategy of administration mAb at birth for all children, 291 out of the 854 candidate strategies, featuring diverse administration timing and age thresholds, demonstrated a greater number of averted RSV-ALRI hospitalizations and a lower number needed to treat (NNT). The NNT represents the number of mAb doses needed to prevent one case of RSV-ALRI hospitalization. Among the 291 strategies, administration mAb to children born in July-January or August-January at birth and administrating to the remaining <12 months old children in September, exhibited the highest increase in averted RSV-ALRI hospitalizations than the year-round strategy, with a magnitude of 23 %, while also achieve an 18 % reduction in NNT.

CONCLUSION

Administrating monoclonal antibodies to children born in July to January at birth, and administrating to the remaining <1-year-old children in September or October would be the optimal seasonal mAb administration strategy for children in Suzhou, China.

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.

Quantification of clesrovimab, an investigational, half-life extended, anti-respiratory syncytial virus protein F human monoclonal antibody in the nasal epithelial lining fluid of healthy adults

BACKGROUND

Clesrovimab (MK-1654) is an investigational, half-life extended human monoclonal antibody (mAb) against RSV F glycoprotein in clinical trials as a prophylactic agent against RSV infection for infants.

METHODS

This adult study measured clesrovimab concentrations in the serum and nasal epithelial lining fluid (ELF) to establish the partitioning of the antibody after dosing. Clesrovimab concentrations in the nasal ELF were normalized for sampling dilution using urea concentrations from ELF and serum. Furthermore, in vitro RSV neutralization of human nasal ELF following dosing was also measured to examine the activity of clesrovimab in the nasal compartment.

FINDINGS

mAbs with YTE mutations are reported in literature to partition ∼1-2 % of serum antibodies into nasal mucosa. Nasal: serum ratios of 1:69-1:30 were observed for clesrovimab in two separate adult human trials after urea normalization, translating to 1.4-3.3 % of serum concentrations. The nasal PK and estimates of peripheral volume of distribution correlated with higher extravascular distribution of clesrovimab. These higher concentration of the antibody in the nasal ELF corroborated with the nasal sample's ability to neutralize RSV ex vivo. An overall trend of decreased viral plaque AUC was also noted with increasing availability of clesrovimab in the nasal ELF from a human RSV challenge study.

INTERPRETATION

Along with its extended half-life, the higher penetration of clesrovimab into the nasal epithelial lining fluid and the associated local increase in RSV neutralization activity could offer infants better protection against RSV infection.

Respiratory syncytial virus disease morbidity in Australian infants aged 0 to 6 months: a systematic review with narrative synthesis

BACKGROUND

A significant proportion of the global respiratory syncytial virus (RSV) associated morbidity is accounted for by infants aged 0 to 6 months, who are particularly vulnerable to severe disease. In 2015, 44% of global hospitalisations in infants in this age group were secondary to RSV. The objective of this systematic review is to appraise and synthesise the local evidence of RSV infection morbidity among Australian infants aged 0 to 6 months and to assess the implications for future immunisation strategies.

METHODS

Electronic databases (Medline, Embase, Pubmed and Global Health) were searched for full-text articles published between 2000 and 2023 in English language. Studies that examined markers of RSV disease morbidity in infants aged 0 to 6 months in Australia who had laboratory confirmed RSV infection were eligible for inclusion. The outcomes of interest were incidence, prevalence, testing rate, positivity rate, mortality, emergency department visits, community health visits, hospitalisation, intensive care unit admission, supplementary oxygen use, mechanical ventilation, risk factors for disease severity and monoclonal antibody use.

RESULTS

The database search identified 469 studies. After removal of duplicates and full-text review, 17 articles were eligible for inclusion. This review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Synthesis without meta-analysis guidelines.

CONCLUSIONS

Qualitative analysis of the included studies showed that Australian infants aged 0 to 6 months have higher rates of RSV testing, positivity and incidence; and more likely to develop severe disease that requires hospitalisation, intensive care unit admission or respiratory support, compared to children and adults of all ages. Aboriginal and Torres Strait Islander infants aged 0 to 6 months demonstrated higher rates of RSV infection and hospitalisation, compared to non-Indigenous infants. Age-related trends persisted in geographic areas with varying seasonal transmission of RSV, and during the SARS-CoV-2 pandemic. Passive immunisation strategies targeting infants in their first 6 months of life, either via vaccination of pregnant women or administration of long-acting monoclonal antibody during infancy, could effectively reduce RSV disease burden in Australia.

Molecular Epidemiology of Respiratory Syncytial Virus during 2019-2022 and Surviving Genotypes after the COVID-19 Pandemic in Japan

To evaluate the changes in respiratory syncytial virus (RSV) collected between 2019 and 2022, we analyzed RSV-A and RSV-B strains from various prefectures in Japan before and after the COVID-19 pandemic. RT-PCR-positive samples collected from children with rapid test positivity at outpatient clinics in 11 prefectures in Japan were sequenced for the ectodomain of the G gene to determine the genotype. Time-aware phylogeographic analyses were performed using the second hypervariable region (HVR) of the G gene from 2012 to 2022. Of 967 samples, 739 (76.4%) were found to be RSV-positive using RT-PCR. RSV peaked in September 2019 but was not detected in 2020, except in Okinawa. Nationwide epidemics occurred with peaks in July 2021 and 2022. The genotype remained the same, ON1 for RSV-A and BA9 for RSV-B during 2019-2022. Phylogeographic analysis of HVR revealed that at least seven clusters of RSV-A had circulated previously but decreased to two clusters after the pandemic, whereas RSV-B had a single monophyletic cluster over the 10 years. Both RSV-A and RSV-B were transferred from Okinawa into other prefectures after the pandemic. The RSV epidemic was suppressed due to pandemic restrictions; however, pre-pandemic genotypes spread nationwide after the pandemic.

Direct long-acting antibodies: updating the language of RSV prevention to reflect the evolution of mAbs

Introduction

The language of medicine is constantly evolving, typically to better describe a new understanding of disease, adjust to changing social sensibilities, or simply to reflect a new drug class or category. We address the need for an updated language around monoclonal antibodies, or "mAbs" - a widely used medical term, but one which is now too general to accurately reflect the range of mAb pharmaceuticals, their effects, and the intended patients.

Methods

The question of "what should we call a monoclonal antibody immunisation against respiratory syncytial virus (RSV) to ensure accurate understanding of the product?" was the basis for a virtual advisory panel in May 2022. The panel was convened by Sanofi with the intention of reviewing appropriate language in terminology in the context of mAb-based prophylaxis for RSV. The panel comprised several global experts on RSV and vaccination, a trained linguist specialising in doctor-patient interactions and medical language, and several experts in marketing and communications.

Results

We suggest the term "Direct Long-acting Antibody" (DLA) for a specific sub-class of mAbs for use in prevention of RSV disease in infants. This terminology should differentiate from other mAbs, which are generally not used as therapies in infants.

Discussion and Conclusions

This change will more accurately convey the specific mode of action of a mAb in infants, and how it could impact the prevention of communicable diseases: this class of mAbs is not an active treatment, but rather will offer direct and rapid protection lasting at least 5 months.

Respiratory syncytial virus: can we still believe that after pandemic bronchiolitis is not a critical issue for public health?

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection among infants and young children, resulting in annual epidemics worldwide. Since the beginning of the COVID-19 pandemic, non-pharmacological interventions were applied, interfering with the circulation of most respiratory viruses, including RSV. The aim of this study is to analyze the RSV infection trend among hospitalized infants during the actual epidemic season (2022-2023) in comparison with the last pre-pandemic season (2018-2019), in order to outline whether significant differences emerge due to COVID-19 pandemia. We retrospectively reviewed medical data on infants hospitalized at the Bambino Gesù Children's Hospital with diagnosis of bronchiolitis in the current epidemic season and in the last pre-pandemic season, 2018-2019. RSV remains the main etiological agent of bronchiolitis in terms of frequency and severity of infections in the ongoing epidemic season. The first RSV case of the 2022-2023 season was detected at week 42 vs week 47 in the 2018-2019 season. The length of epidemic season was of 17 weeks in 2022-2023 vs 18 weeks in 2018-2019. Comparing the two seasons, age at admission was significantly higher in the current season (median age 2022-2023 65 days vs median age 2018-2019 58 days), but the disease severity was similar.       Conclusions: The 2022-2023 bronchiolitis season in Italy started earlier than the usual pre-pandemic seasons but seasonality pattern may be going back to the pre-pandemic one. This season was not more severe than the previous ones. The impact of RSV disease on health care systems and costs remains a critical issue. What is Known: • RSV is one of the major leading causes of hospitalization among children aged less than 3 months. SarsCOV2 pandemic interfered with the seasonal circulation of most respiratory viruses, Including RSV. What is New: • The 2022-2023 bronchiolitis season in Italy started and peaked earlier than the usual pre-pandemic seasons but seasonality pattern may be realigning to the pre-pandemic one. The impact of RSV disease on health care systems and costs is concerning.

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.

Prospective Attitudes towards Respiratory Syncytial Virus (RSV) Vaccination: Validation of a Survey Instrument among Young Females in Jordan Pending Vaccine Authorization

In May 2023, the U.S. FDA advisors endorsed Pfizer's pregnancy-administered vaccine (branded ABRYSVO) to protect infants from respiratory syncytial virus (RSV) infection. Vaccination can reduce the burden of RSV-related respiratory disease, with previous studies showing its substantial medical and financial burden in Jordan. However, pregnant women may exhibit hesitancy to get vaccinated due to concerns about potential risks to themselves or their fetuses. This study aimed to assess the acceptance of the RSV vaccine among young females and identify the determinants influencing their decision using a newly constructed instrument. A survey instrument was developed and validated, comprising 26 items to measure RSV vaccine acceptance. A cross-sectional study design was employed, with data collection from a sample of females aged 18 to 45 residing in Jordan during 5-6 July 2023, using a convenient approach via an online distributed questionnaire. The final study sample comprised 315 respondents, with 67.6% who have heard of RSV before the study. If the vaccine was safe, effective, and provided freely, 70.2% showed willingness to get the RSV vaccine, 15.2% resisted, and 14.6% were hesitant. Principal component analysis identified six internally consistent sub-scales with the following suggested themes: Advice, Burden, Conspiracy, Dangers, Efficiency, and Fear, comprising 21 items collectively as assigned as the "ABCDEF" scale for RSV vaccine acceptance. RSV vaccine acceptance in this study was associated with the advice and fear constructs. The validated survey instrument successfully captured important determinants of RSV vaccine acceptance among young females. RSV vaccine promotion efforts should focus on the following: enhancing vaccine education, improving trust in healthcare institutions and providers, reducing burdens through resolving cost issues and focusing on the role of social support, addressing safety concerns, and tailoring communication strategies to effectively promote the benefits of the vaccine. These insights can inform public health policies and interventions aiming to promote RSV vaccination and mitigate the burden of RSV-related diseases among infants. Follow-up studies are recommended with pregnant women as the target group to assess their attitude towards RSV vaccination and to confirm the validity of the conceived ABCDEF survey instrument.

Risk Factors for Severe Respiratory Syncytial Virus Infection in Hospitalized Children

BACKGROUND

RSV often leads to hospitalization, and accurate knowledge of risk factors is crucial.

METHODS

We retrospectively analyzed laboratory-confirmed RSV hospitalizations regarding pregnancy factors, birth status, cigarette smoke exposure, nutrition, social conditions, clinical presentation, and severe disease defined as a need for passive oxygen therapy (pO2Tx), the presence of pneumonia, respiratory failure, intensive care unit (ICU) transfer, and prolonged hospitalization.

RESULTS

A univariate analysis included 594 children (median age 4 months) and revealed a pO2Tx relationship with age ≤ 3 months (OR = 1.56), prematurity (OR = 1.71), being born during RSV season (OR = 1.72), smoke exposure during pregnancy (both parents (OR = 2.41, father (OR = 1.8)), dyspnea (OR = 5.09), and presence of apnea (OR = 5.81). Pneumonia was associated with maternal smoke exposure (OR = 5.01), fever (OR = 3.92), dyspnea (OR = 1.62), history of aspiration (OR = 4.63), and inversely with age ≤ 3 months (OR = 0.45). Respiratory failure was associated with prematurity (OR = 3.13) and apnea (OR = 18.78), while the lower odds were associated with older age (OR = 0.57 per month) and presence of fever (OR = 0.11). ICU transfer was associated with apnea (OR = 17.18), but an inverse association was observed with age (OR = 0.54) and fever (OR = 0.11). A prolonged hospital stay was associated with prematurity (OR = 1.76), low birth weight (OR = 2.89), aspiration (OR = 4.93), and presence of fever (OR = 1.51).

CONCLUSIONS

Age (up to 3 months), prematurity, and presence of apnea are risk factors for a severe RSV course.

Respiratory Syncytial Virus: A Systematic Review and Meta-Analysis of Tomographic Findings (2000-2022)

Human respiratory syncytial virus (RSV) is a main cause of medical referrals and hospitalizations in all infants, particularly among newborns. Nevertheless, relatively limited evidence on chest tomography (CT) findings has been collected. According to the PRISMA statement, Pubmed, Embase, and medRxiv were searched for eligible observational studies published up to 31 December 2022. Cases were categorized in children and adolescents (age < 18 years), adults and elderly (age ≥ 18 years), and immunocompromised patients, and then pooled in a random-effects model. Heterogeneity was assessed using the I2 statistics, while reporting bias was assessed by means of funnel plots and regression analysis. A total of 10 studies (217 RSV cases) were retrieved (children, 37.3%; immunocompromised, 41.0%; adults, 21.7%). The most common features were signs of organizing pneumonia (33.65%, 95% confidence interval [95% CI] 22.39-47.27), followed by septal thickening (33.19%, 95% CI 21.76-47.03), ground glass opacities (GGOs; 28.03%, 95% CI 14.69-46.82), and tree-in-bud (TIB, 27.44%, 95% CI 15.04-44.68). Interestingly, up to 16.23% (95% CI 8.17-29.69) showed normal findings, while the large majority (76.06%, 95% CI 64.81-84.56) were characterized by bilateral involvement. Studies were highly heterogeneous without substantial reporting bias. Assuming children and adolescents as reference groups, healthy adults were characterized by a higher risk ratio [RR] for septal thickening (RR 3.878, 95% CI 1.253-12.000), nodular lesions (RR 20.197, 95% CI 1.286-317.082), and GGOs (RR 2.121, 95% CI 1.121-4.013). RSV cases are rarely assessed in terms of CT characteristics. Our study identified some specificities, suggesting that RSV infections evolve heterogeneous CT features in children/adolescents and adults, but the paucity of studies recommends a cautious appraisal.

Exploring the adoption of less restricted criteria for respiratory syncytial virus prophylaxis in late preterm infants: insights from a retrospective analysis

Background

Preterm infants born between 33 and 35 weeks of gestational age (wGA) have been considered a "major underserved population" and ineligible to receive palivizumab (PLV), the only drug authorized to date for respiratory syncytial virus (RSV) prophylaxis, by current international guidelines. In Italy, such a vulnerable population is currently eligible for prophylaxis, and, in our region, specific risk factors are taken into consideration (SIN_Lazio score) to target prophylaxis for those at highest risk. Whether the adoption of less or more restrictive eligibility criteria for PLV prophylaxis would translate into differences in bronchiolitis and hospitalization incidence is not known.

Materials and methods

A retrospective analysis was conducted in 296 moderate-to-late preterm infants (born between 33 and 35⁺⁶ weeks) who were being considered for prophylaxis in two epidemic seasons: 2018-2019 and 2019-2020. The study participants were categorized according to both the SIN_Lazio score and the Blanken risk scoring tool (BRST), which was found to reliably predict RSV-associated hospitalization in preterm infants on the basis of three risk factor variables.

Results

Based on the SIN_Lazio score, approximately 40% of infants (123/296) would meet the criteria to be eligible for PLV prophylaxis. In contrast, none of the analyzed infants would be considered eligible for RSV prophylaxis on the basis of the BRST. A total of 45 (15.2%) bronchiolitis diagnoses were recorded on average at 5 months of age in the overall population. Almost seven out of 10 (84/123) patients exhibiting ≥3 risk factors to be eligible for RSV prophylaxis according to SIN_Lazio criteria would not be receiving PLV if they were categorized on the basis of the BRST. Bronchiolitis occurrence in patients with a SIN_Lazio score ≥3 was approximately 2.2 times more likely than that in patients with a SIN_Lazio score <3. PLV prophylaxis has been associated with a 91% lower risk of requiring a nasal cannula.

Conclusion

Our work further supports the need for targeting late preterm infants for RSV prophylaxis and calls for an appraisal of the current eligibility criteria for PLV treatment. Therefore, adopting less restrictive criteria may ensure a comprehensive prophylaxis of the eligible subjects, thus sparing them from avoidable short- and long-term consequences of RSV infection.

Respiratory Syncytial Virus-An Update for Prenatal and Primary Health Providers

Respiratory syncytial virus (RSV) infection is a significant cause of morbidity and mortality among infants aged younger than 1 year, adults aged 65 years or older, and immunocompromised persons. Limited data exist on RSV infection in pregnancy and further research is needed. Strides are being made to develop vaccines, including vaccines for maternal immunization, as well as monoclonal antibodies for disease prevention.

Monoclonal antibodies for prophylaxis and therapy of respiratory syncytial virus, SARS-CoV-2, human immunodeficiency virus, rabies and bacterial infections: an update from the World Association of Infectious Diseases and Immunological Disorders and the Italian Society of Antinfective Therapy

Monoclonal antibodies (mABs) are safe and effective proteins produced in laboratory that may be used to target a single epitope of a highly conserved protein of a virus or a bacterial pathogen. For this purpose, the epitope is selected among those that play the major role as targets for prevention of infection or tissue damage. In this paper, characteristics of the most important mABs that have been licensed and used or are in advanced stages of development for use in prophylaxis and therapy of infectious diseases are discussed. We showed that a great number of mABs effective against virus or bacterial infections have been developed, although only in a small number of cases these are licensed for use in clinical practice and have reached the market. Although some examples of therapeutic efficacy have been shown, not unlike more traditional antiviral or antibacterial treatments, their efficacy is significantly greater in prophylaxis or early post-exposure treatment. Although in many cases the use of vaccines is more effective and cost-effective than that of mABs, for many infectious diseases no vaccines have yet been developed and licensed. Furthermore, in emergency situations, like in epidemics or pandemics, the availability of mABs can be an attractive adjunct to our armament to reduce the impact. Finally, the availability of mABs against bacteria can be an important alternative, when multidrug-resistant strains are involved.

Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants

BACKGROUND

Whether vaccination during pregnancy could reduce the burden of respiratory syncytial virus (RSV)-associated lower respiratory tract illness in newborns and infants is uncertain.

METHODS

In this phase 3, double-blind trial conducted in 18 countries, we randomly assigned, in a 1:1 ratio, pregnant women at 24 through 36 weeks' gestation to receive a single intramuscular injection of 120 μg of a bivalent RSV prefusion F protein-based (RSVpreF) vaccine or placebo. The two primary efficacy end points were medically attended severe RSV-associated lower respiratory tract illness and medically attended RSV-associated lower respiratory tract illness in infants within 90, 120, 150, and 180 days after birth. A lower boundary of the confidence interval for vaccine efficacy (99.5% confidence interval [CI] at 90 days; 97.58% CI at later intervals) greater than 20% was considered to meet the success criterion for vaccine efficacy with respect to the primary end points.

RESULTS

At this prespecified interim analysis, the success criterion for vaccine efficacy was met with respect to one primary end point. Overall, 3682 maternal participants received vaccine and 3676 received placebo; 3570 and 3558 infants, respectively, were evaluated. Medically attended severe lower respiratory tract illness occurred within 90 days after birth in 6 infants of women in the vaccine group and 33 infants of women in the placebo group (vaccine efficacy, 81.8%; 99.5% CI, 40.6 to 96.3); 19 cases and 62 cases, respectively, occurred within 180 days after birth (vaccine efficacy, 69.4%; 97.58% CI, 44.3 to 84.1). Medically attended RSV-associated lower respiratory tract illness occurred within 90 days after birth in 24 infants of women in the vaccine group and 56 infants of women in the placebo group (vaccine efficacy, 57.1%; 99.5% CI, 14.7 to 79.8); these results did not meet the statistical success criterion. No safety signals were detected in maternal participants or in infants and toddlers up to 24 months of age. The incidences of adverse events reported within 1 month after injection or within 1 month after birth were similar in the vaccine group (13.8% of women and 37.1% of infants) and the placebo group (13.1% and 34.5%, respectively).

CONCLUSIONS

RSVpreF vaccine administered during pregnancy was effective against medically attended severe RSV-associated lower respiratory tract illness in infants, and no safety concerns were identified. (Funded by Pfizer; MATISSE ClinicalTrials.gov number, NCT04424316.).

Respiratory Syncytial Virus Outbreak in Infants and Young Children during COVID-19 Pandemic in Taiwan

Respiratory syncytial virus (RSV) is a major burden of disease in babies and young children, including hospitalizations and deaths. RSV is a seasonal disease that peaks when temperatures decrease in temperate zones and humidity increases in tropical regions. Existing research reveals that RSV hospitalization activity is year-round in Taiwan, which is a subtropical region with small peaks in spring and fall. The monthly distribution and COVID-19 pandemic impact were unclear. The aim of this study was to investigate Taiwan’s RSV hospitalization seasonality and the COVID-19 pandemic effects. The National Health Insurance Database and Death Registration Files from the Center for Health and Welfare Data Science Center were connected to birth data for this study. RSV hospitalization (RSVH) in infants aged 0–1 years ranged from 0.9518% (2009) to 1.7113% (2020), substantially higher than in children aged 1–5. Most years had 2 or 3 RSV epidemic seasons in 0–5-year-olds over the 13-year follow-up. RSVH incidence was low until the autumn of 2020, when a major rise occurred after September and lasted until December 2020. We detected RSVH peaks in February–May and July–August. The 2020 RSV outbreak was found at the end of 2020.

Hemogram-based decision tree models for discriminating COVID-19 from RSV in infants

OBJECTIVE

Decision trees are efficient and reliable decision-making algorithms, and medicine has reached its peak of interest in these methods during the current pandemic. Herein, we reported several decision tree algorithms for a rapid discrimination between coronavirus disease (COVID-19) and respiratory syncytial virus (RSV) infection in infants.

METHODS

A cross-sectional study was conducted on 77 infants: 33 infants with novel betacoronavirus (SARS-CoV-2) infection and 44 infants with RSV infection. In total, 23 hemogram-based instances were used to construct the decision tree models via 10-fold cross-validation method.

RESULTS

The Random forest model showed the highest accuracy (81.8%), while in terms of sensitivity (72.7%), specificity (88.6%), positive predictive value (82.8%), and negative predictive value (81.3%), the optimized forest model was the most superior one.

CONCLUSION

Random forest and optimized forest models might have significant clinical applications, helping to speed up decision-making when SARS-CoV-2 and RSV are suspected, prior to molecular genome sequencing and/or antigen testing.

Respiratory Syncytial Virus Prevention through Monoclonal Antibodies: A Cross-Sectional Study on Knowledge, Attitudes, and Practices of Italian Pediatricians

Respiratory Syncytial Virus (RSV) is a leading cause of morbidity and hospitalization in all infants. Many RSV vaccines and monoclonal antibodies (mAb) are currently under development to protect all infants, but to date preventive options are available only for preterms. In this study, we assessed the knowledge, attitudes, and practices towards RSV and the preventive use of mAb in a sample of Italian Pediatricians. An internet survey was administered through an internet discussion group, with a response rate of 4.4% over the potential respondents (No. 389 out of 8842, mean age 40.1 ± 9.1 years). The association of individual factors, knowledge, and risk perception status with the attitude towards mAb was initially inquired by means of a chi squared test, and all variables associated with mAb with p < 0.05 were included in a multivariable model calculating correspondent adjusted Odds Ratio (aOR) with 95% confidence intervals (95%CI). Of the participants, 41.9% had managed RSV cases in the previous 5 years, 34.4% had diagnosed RSV cases, and 32.6% required a subsequent hospitalization. However, only 14.4% had previously required mAb as immunoprophylaxis for RSV. Knowledge status was substantially inappropriate (actual estimate 54.0% ± 14.2, potential range 0-100), while the majority of participants acknowledged RSV as a substantial health threat for all infants (84.8%). In multivariable analysis, all these factors were characterized as positive effectors for having prescribed mAb (aOR 6.560, 95%CI 2.904-14.822 for higher knowledge score; aOR 6.579, 95%CI 2.919-14.827 for having a hospital background, and a OR 13.440, 95%CI 3.989; 45.287 for living in Italian Major Islands). In other words, reporting less knowledge gaps, having worked in settings with a higher risk of interaction with more severe cases, and being from Italian Major Islands, were identified as positive effectors for a higher reliance on mAb. However, the significant extent of knowledge gaps highlights the importance of appropriate medical education on RSV, its potential health consequences, and the investigational preventive interventions.

UPDATE - 2022 Italian guidelines on the management of bronchiolitis in infants

Bronchiolitis is an acute respiratory illness that is the leading cause of hospitalization in young children. This document aims to update the consensus document published in 2014 to provide guidance on the current best practices for managing bronchiolitis in infants. The document addresses care in both hospitals and primary care. The diagnosis of bronchiolitis is based on the clinical history and physical examination. The mainstays of management are largely supportive, consisting of fluid management and respiratory support. Evidence suggests no benefit with the use of salbutamol, glucocorticosteroids and antibiotics with potential risk of harm. Because of the lack of effective treatment, the reduction of morbidity must rely on preventive measures. De-implementation of non-evidence-based interventions is a major goal, and educational interventions for clinicians should be carried out to promote high-value care of infants with bronchiolitis. Well-prepared implementation strategies to standardize care and improve the quality of care are needed to promote adherence to guidelines and discourage non-evidence-based attitudes. In parallel, parents' education will help reduce patient pressure and contribute to inappropriate prescriptions. Infants with pre-existing risk factors (i.e., prematurity, bronchopulmonary dysplasia, congenital heart diseases, immunodeficiency, neuromuscular diseases, cystic fibrosis, Down syndrome) present a significant risk of severe bronchiolitis and should be carefully assessed. This revised document, based on international and national scientific evidence, reinforces the current recommendations and integrates the recent advances for optimal care and prevention of acute bronchiolitis.