Severe RSV Research Articles

Pertussis and pertussis-like syndrome in young children

The most common infectious diseases with a risk of severe, non-smooth course and unfavorable outcome in young children, including the first year of life, are pertussis and respiratory syncytial viral infection (RSV infection), often occurring with pertussis-like syndrome.Objective: to establish clinical and laboratory differential diagnostic criteria for pertussis and RSV infection in children of the first year of life.Materials and methods: A retrospective comparative study was conducted, which included patients of the first year of life (from 1 month to 11 months and 29 days), regardless of the duration of hospitalization and duration of the disease: 48 patients with pertussis and 26 with acute RSV infection.Results: The compared groups of patients were comparable in age, the number of severe forms (4.6 ± 0.5 months, 17% for pertussis and 4.0 ± 0.2 months, 16% for RS infection). The disease in both cases began subacute, however, with RSV infection 92% of children were hospitalized in the first 5 days from the onset of the disease, with pertussis — in the first week of the period of convulsive cough — 47.9%, in the second week — 41.7%, in the third week — 10.4%. 52% of patients with RSV infection had no fever or (in 32%) did not exceed 1—3 days. In 41.3% of patients it was subfebrile (37—38 °C), in 21.1% it was febrile (38—39 °C). In patients with pertussis the onset of the disease took place against the background of normal body temperature. In patients with RSV infection, bronchiolitis was recorded in 24% of cases, obstructive bronchitis — in 60%. Patients with pertussis, 89.6% of whom were not vaccinated and 10.4% did not complete the initial course of vaccination, had a typical paroxysmal cough with reprises. Complications in the form of respiratory rhythm disturbances were recorded in 14.6% of cases, pneumonia — in 6.3%. Comparison of hematological parameters revealed highly significant differences in the levels of leukocytosis and relative lymphocytosis (p < 0.001), as well as thrombocytosis (p < 0.01), with the predominance of all indicators in patients with pertussis.Conclusion. Differential diagnostic criteria for the similarity of the clinical picture may be established hematological differences: pronounced leukocytosis due to lymphocytosis, increasing in dynamics, and thrombocytosis in pertussis and normocytosis with moderate lymphocytosis, a possible tendency to thrombocytosis in severe RSV infection.

Infecciones por virus respiratorio sincitial que requieren hospitalización en pacientes con inmunodeficiencias primarias

IntroductionThe aim of the study was to assess the incidence of hospital admission due to severe acute respiratory infection by respiratory syncytial virus (RSV-ARI) in children with primary immunodeficiencies (PIDs) and the severity of RSV-ARI in these patients. MethodsWe conducted a nationwide cross-sectional retrospective and prospective multicentre study in the 2011-2017 period. The study was performed in 15 Spanish hospitals and included children with PID who required hospital admission due to RSV-ARI. ResultsOut of 439 patients with PID followed up at participating hospitals, 13 (3%) required hospital admission due to RSV-ARI. The median age of admitted patients was 1.6years (interquartile range, 0.5-2.2), and 7 were male. The types of PID most frequently associated with admission due to RSV-ARI were combined immunodeficiency (CID; 4/71 [6%]) and CID with associated or syndromic features (CIDwASF; 6/147 [4%]). Two of the 13 patients were receiving palivizumab for RSV prophylaxis, and 3 received potentially active therapies against RSV during the hospital stay. Viral coinfection was detected in 6 patients, 5 (39%) developed complications, and 4 (31%) required admission to the paediatric intensive care unit. There were no documented RSV-related deaths. ConclusionsIn the group of patients with PID, severe RSV infection requiring hospitalization is more frequent in patients with CID and CIDwASF, in whom special efforts should be made to prevent RSV infection. Further studies are needed to confirm these results.

Live-Attenuated Vaccines Prevent Respiratory Syncytial Virus-Associated Illness in Young Children

To determine the preliminary efficacy and durability of live-attenuated respiratory syncytial virus RSV vaccine candidates from phase 1 clinical trials.Healthy RSV-naïve children aged 6 to 24 months (n = 241) were randomly assigned 2:1 to receive either a live-attenuated RSV vaccine or placebo.Separate trials of 7 different RSV vaccine candidates were similarly conducted, and data were pooled for analysis. The surveillance period was from ∼5.5 to 13 months after day 56 postvaccination. The RSV neutralizing antibody (NeutAb) response, also considered indicative of vaccine efficacy, was defined as more than a fourfold increase in complement-enhanced plaque reduction-neutralizing antibody titers after vaccination. Data were further grouped by “more promising” vaccines (NeutAb response in ≥80% of vaccine recipients; n = 5) and “less promising” (NeutAb response in ≤59% of vaccines; n = 2).There was 66% efficacy against respiratory syncytial virus–associated medically attended acute respiratory illness (RSV-MAARI) infections (P = .007) and 100% efficacy against respiratory syncytial virus–associated medically attended acute lower respiratory illness (RSV-MAALRI) (P = .009) among all NeutAb responders. A NeutAb response overall was significantly associated with protection against RSV-MAARI and RSV-MAALRI (odds ratio: 0.26; 95% confidence interval: 0.09 to 0.75; P = .014). Vaccine virus titers shed by vaccine recipients did not correlate with protection against RSV-MAARI or RSV-MAALRI. Although there was no significant difference in the primary NeutAb responses between the vaccinated and placebo groups (P = .21), the magnitude of anamnestic NeutAb response was ∼10-fold higher in vaccine recipients than in those with the placebo after infection with wild-type RSV during surveillance (P = .0001). In the vaccinated group not infected with wild-type RSV (n = 89), the postsurveillance anamnestic NeutAb titers (79 [6.3 log2]) were less than postimmunization (111 [6.8 log2]; P < .001); however, the absolute difference was small. On the basis of the disease rate model, the authors determined that future study sample sizes between 540 and 1300 would be needed to demonstrate efficacy.Live-attenuated RSV vaccines provide protection against acute respiratory and lower respiratory illnesses and can produce durable response.Currently, palivizumab, a monoclonal antibody, is still the only Food and Drug Administration–approved medication for RSV, providing short-term prophylaxis against severe RSV disease in high-risk infants and children with preexisting conditions, such as prematurity with or without bronchopulmonary dysplasia. The preliminary data from these small clinical trials identifying these “more promising” vaccines suggest that we may be 1 step closer toward actually developing an RSV vaccine that can protect against infection and address the burden of RSV disease. Obvious considerations for future and later stage clinical trials include appropriately powered sample sizes (including RSV-exposed subjects), study duration, geographic locations, timing of the RSV season, and vaccine delivery routes and dosing.

Describing global pediatric RSV disease at intensive care units in GAVI-eligible countries using molecular point-of-care diagnostics: the RSV GOLD-III study protocol

BackgroundRespiratory syncytial virus (RSV) infection is an important cause of hospitalization and death in young children. The majority of deaths (99%) occur in low- and lower-middle-income countries (LMICs). Vaccines against RSV infection are underway. To obtain access to RSV interventions, LMICs depend on support from Gavi, the Vaccine Alliance. To identify future vaccine target populations, information on children with severe RSV infection is required. However, there is a lack of individual patient-level clinical data on instances of life-threatening RSV infection in LMICs. The RSV GOLD III—ICU Network study aims to describe clinical, demographic and socioeconomic characteristics of children with life-threatening RSV infection in Gavi-eligible countries.MethodsThe RSV GOLD-III—ICU Network study is an international, prospective, observational multicenter study and will be conducted in 10 Gavi-eligible countries at pediatric intensive care units and high-dependency units (PICUs/HDUs) during local viral respiratory seasons for 2 years. Children younger than 2 years of age with respiratory symptoms fulfilling the World Health Organization (WHO) “extended severe acute respiratory infection (SARI)” case definition will be tested for RSV using a molecular point-of-care (POC) diagnostic device. Patient characteristics will be collected through a questionnaire. Mortality rates of children admitted to the PICU and/or HDU will be calculated.DiscussionThis multicenter descriptive study will provide a better understanding of the characteristics and mortality rates of children younger than 2 years with RSV infection admitted to the PICU/HDU in LMICs. These results will contribute to knowledge on global disease burden and awareness of RSV and will directly guide decision makers in their efforts to implement future RSV prevention strategies.Trial registration number: NL9519, May 27, 2021

Relationship between neighborhood census-tract level socioeconomic status and respiratory syncytial virus-associated hospitalizations in U.S. adults, 2015\u20132017

BackgroundRespiratory syncytial virus (RSV) infection causes substantial morbidity and mortality in children and adults. Socioeconomic status (SES) is known to influence many health outcomes, but there have been few studies of the relationship between RSV-associated illness and SES, particularly in adults. Understanding this association is important in order to identify and address disparities and to prioritize resources for prevention.MethodsAdults hospitalized with a laboratory-confirmed RSV infection were identified through population-based surveillance at multiple sites in the U.S. The incidence of RSV-associated hospitalizations was calculated by census-tract (CT) poverty and crowding, adjusted for age. Log binomial regression was used to evaluate the association between Intensive Care Unit (ICU) admission or death and CT poverty and crowding.ResultsAmong the 1713 cases, RSV-associated hospitalization correlated with increased CT level poverty and crowding. The incidence rate of RSV-associated hospitalization was 2.58 (CI 2.23, 2.98) times higher in CTs with the highest as compared to the lowest percentages of individuals living below the poverty level (≥ 20 and < 5%, respectively). The incidence rate of RSV-associated hospitalization was 1.52 (CI 1.33, 1.73) times higher in CTs with the highest as compared to the lowest levels of crowding (≥5 and < 1% of households with > 1 occupant/room, respectively). Neither CT level poverty nor crowding had a correlation with ICU admission or death.ConclusionsPoverty and crowding at CT level were associated with increased incidence of RSV-associated hospitalization, but not with more severe RSV disease. Efforts to reduce the incidence of RSV disease should consider SES.

Study protocol: a multicenter, uncontrolled, open-label study of palivizumab in neonates, infants, and preschool children at high risk of severe respiratory syncytial virus infection

BackgroundThe prophylactic use of anti-respiratory syncytial virus (RSV) antibody (palivizumab) for severe RSV infection is not approved in Japan in specified groups of infants with neuromuscular diseases or other rare diseases associated with reduced ventilation competence or difficulty in expectoration, which increase the risk of exacerbation of severe RSV infection. The objective of this study is to investigate the efficacy, safety, and pharmacokinetics of palivizumab in pediatric patients with those rare diseases for which palivizumab is not indicated at present.Methods/designThis study is a multicenter, uncontrolled, open-label study planned to be carried out between July 1, 2019 and June 30, 2022 at 7 medical institutions in Japan. The study population will be recruited from among neonates, infants, or children aged 24 months or younger with a condition falling under any of the following 5 disease groups: pulmonary hypoplasia, airway stenosis, congenital esophageal atresia, inherited metabolic disease, or neuromuscular disease. The planned sample size is 18 subjects, including at least 3 subjects per disease group. Throughout the RSV season, at least 4 continuous doses of palivizumab will be administered intramuscularly at 15 mg/kg at intervals of 30 days. The efficacy and safety of palivizumab will be comprehensively evaluated based on the incidence of RSV-related hospitalization, and serum palivizumab concentration, serum anti-palivizumab antibody concentration, and the occurrence of adverse events/reactions after the start of palivizumab treatment.DiscussionThis study will evaluate the efficacy and safety of palivizumab in pediatric patients with rare diseases which place them at high risk of severe RSV infection, but which fall outside the current indications for palivizumab prophylaxis. The generated data will have implications for the regulatory approval of prophylactic palivizumab treatment in this patient group.Trial registrationThis study has been prospectively registered in Japic Clinical Trials Information, which is managed and administered by the Japan Pharmaceutical Information Center (registration number: JapicCTI-194946, registration date: September 10, 2019).

Occurrence and severity of acute respiratory infections during the first year among very preterm infants: an Epipage-2 cohort analysis.

This study aims to describe the incidence of acute respiratory infections (ARI) during the first year in infants born before 32 weeks' gestation, and to analyze and study the risk factors as well as factors associated with oxygen requirement among infants with an ARI, in the palivizumab era. This study included 2571 infants from a nationwide French population-based cohort (Epipage 2). ARI at 1-year corrected age was identified by parental questionnaires. Risk and severity factors included those already known, and detailed information about neonatal morbidities. ARI occurred in 52.2% (n = 1349) of infants. Oxygen therapy was used in 33.2% (n = 391) of infants with an ARI. Risk factors for AII were male sex, bronchopulmonary dysplasia, presence of siblings at home, and childcare in the community together with incomplete treatment palivizumab. Mechanical ventilation in the neonatal period, bronchopulmonary dysplasia, and discharge between October and March were associated with more frequent oxygen requirement. No other factors describing neonatal morbidities were associated with risk of ARI or oxygen requirement.Conclusion: ARIs are still very common during the first year of life of very preterm children, and oxygen therapy is frequently needed. Educational strategies are needed in all families with a very preterm infant. What is Known: • Acute respiratory infections (ARIs) are the first cause of rehospitalizations in preterm children, with bronchopulmonary dysplasia being the main risk factor. • Palivizumab prophylaxis has proven its effect against severe RSV infections, but it is not universal. What is New: • No factor describing neonatal morbidity, except BPD, was associated with ARI occurrence or severity. • BPD and discharge during RSV season were the only factors associated with O2 requirement during ARI.

Invasive Pulmonary Aspergillosis in Influenza and RSV: A Retrospective Cohort Study

Background: Recent studies in Europe and Asia have reported high incidences of invasive pulmonary aspergillosis (IPA) in patients with severe viral respiratory infections, even among immunocompetent individuals. Few large-scale studies have been done in the United States to understand the incidence of IPA in this population. Methods: Data was collected retrospectively on all patients with influenza or RSV infection admitted to the intensive care unit (ICU) at a single academic center in Chicago, IL between May 2008 and May 2018. IPA cases were defined using AspICU criteria. Baseline characteristics, demographics, disease severity, and outcomes were compared by Fisher exact and Mann-Whitney U tests for categorical and continuous variables. Findings: A total of 224 ICU patients with influenza and 153 with RSV met inclusion criteria over nine years. Among those, 7 (3·1%) patients with severe influenza and 8 (5·2%) with severe RSV were diagnosed with IPA based on the modified AspICU criteria. Among patients with severe influenza, history of hematopoietic stem cell transplantation was significantly associated with IPA, while history of hematopoietic stem cell transplantation, hematologic malignancy, and neutropenia were significantly associated with IPA in patients with severe RSV infection. Interpretation: The incidence of IPA complicating severe viral respiratory infection was significantly lower in our study compared to some European and Asian studies. Additionally, the majority of patients in our study had significant immunocompromising risk factors. Funding: This work was supported by the National Institutes of Health T32 Training grant [5T32AI095207] and data collection was supported by NCATS grant (UL1TR001422). Declaration of Interest: HHN and CV have no potential conflicts of interest to declare. MGI received research support, paid to Northwestern University, from AiCuris, Astellas, GlaxoSmithKline, Janssen and Shire; he is a paid consultant for Adagio, AlloVir, Celltrion, Cidara, Genentech, Roche, Janssen, Shionogi, Viracor Eurofins; he is also a paid member of DSMBs from CSL Behring, Janssen, Merck, SAB Biotherapeutics, Sequiris and Takeda; he receives royalty from UpToDate. Ethical Approval: This study was approved by the Northwestern Memorial Hospital Institutional Review Board office.

1465. Age-Dependent Interactions Among Clinical Characteristics, Viral Loads and Disease Severity in Young Children with Respiratory Syncytial Virus Infection (RSV) Infection

BackgroundDifferences in clinical presentation and viral loads according to age in young children with RSV, and their correlation with disease severity are poorly defined. The aim of this study was to define age-dependent the differences in demographic, clinical factors and viral loads between children < 2 years of age with mild RSV infection evaluated as outpatients versus those hospitalized with severe RSV infection.Figure 1. Sign and Symptoms according to disease severity and age in infants with RSV infection. Most relevant signs and symptoms were stratified in outpatients (orange) vs inpatients (blue) by age in (A) < 3 months, (B) between 3 and 6 months, and (C) > 6 to 24 months of age. The Y axis represents the signs and symptoms in the two disease severity groups and the X axis the frequency of that specific symptom (%). Numbers next to bars represent the exact number of patients with that specific sign/symptom. Comparisons by Fisher exact test. Symbol (*) indicate significant 2-sided p values Figure 2. Viral load differences according to age in infants with RSV infection. The Y axis represents RSV loads in log10 copies/mL and the X axis differences in viral loads in outpatients (orange) and inpatients (blue) in the three age groups. Comparisons by Mann Whitney test. MethodsPreviously healthy children < 2 years old with mild (outpatients) and severe (inpatients) RSV infection were enrolled and nasopharyngeal swabs were obtained for RSV typing and quantitation by real-time PCR. Patients were stratified by age (0-< 3, 3-6, and >6-24 months) and multivariable analyses were performed to identify clinical and viral factors associated with severe disease.ResultsFrom 2014-2018 we enrolled 534 children with RSV infection: 130 outpatients and 404 inpatients. Median duration of illness was 4 days for both groups, yet viral loads were higher in outpatients than inpatient in the three age groups (Fig 1). Wheezing was more frequent in outpatients of older age (>3 months) than in inpatients (p< 0.01), while fever was more common in inpatients that outpatients (p< 0.01) and increased with age (Fig 2). Adjusted analyses confirmed that increased work of breathing and fever were consistently associated with hospitalization irrespective of age, while wheezing in infants >3 months, and higher RSV loads in children >6-24 months were independently associated with reduced disease severity.ConclusionAge had a significant impact defining the interactions among viral loads, specific clinical manifestations and disease severity in children with RSV infection. These observations highlight the importance of patient stratification when evaluating interventions against RSV.Disclosures Octavio Ramilo, MD, Bill & Melinda Gates Foundation (Grant/Research Support)Janssen (Grant/Research Support, Advisor or Review Panel member)Medimmune (Grant/Research Support)Merck (Advisor or Review Panel member)NIH/NIAID (Grant/Research Support)Pfizer (Consultant, Advisor or Review Panel member)Sanofi/Medimmune (Consultant, Advisor or Review Panel member) Asuncion Mejias, MD, PhD, MsCS, Janssen (Grant/Research Support, Advisor or Review Panel member)Merck (Advisor or Review Panel member)Roche (Advisor or Review Panel member)

1496. Aspergillosis Complicating Severe Respiratory Syncytial Virus (RSV) in ICU Patients: A Retrospective Cohort Study

BackgroundThere are recent reports that identify severe influenza pneumonia as an independent risk factor for the development of invasive pulmonary aspergillosis (IPA), even in patients without immunocompromise. We aimed to understand the incidence of IPA as well as other coinfections over multiple seasons in patients with RSV pneumonia in the intensive care unit (ICU).MethodsA retrospective cohort study was conducted in a single center in Chicago. Data was collected over 9 seasons (January 2009-March 2018) from adult patients admitted to the ICU at a large urban tertiary care center with severe RSV pneumonia. Patients were included if they had a positive RSV PCR test, older than 18 years, admitted to the ICU with acute respiratory failure, and had pulmonary infiltrates on imaging. IPA was defined per both the EORTC/MSG criteria as well as the revised AspICU criteria (Schauwvlieghe et al). Descriptive statistics were calculated. In univariable analysis, we compared categorical variables by Fisher’s exact test and Chi-square test, continuous variables by Wilcoxon Rank Sum where appropriate.ResultsOf 224 patients admitted to the ICU with RSV (median ICU LoS 10.5 d), IPA was diagnosed in 8 (3.5%). Patients diagnosed with IPA had an increased LoS in the hospital (23.7 days vs. 11.6 days, p=0.01). Although the mortality was numerically higher (3, 37.5% vs 26, 17.9%) this was statistically not significant). History of hematological malignancy, stem cell transplant, and neutropenia were significant factors in the development of IPA. Those with lung disease had significantly lower rates of IPA. All patients with IPA were treated with voriconazole. Other coinfections among RSV-infected ICU patients included bacterial (21, 13.7%), viral (10, 6.5%), and non-IPA fungal (13, 8.5%) pathogens.Baseline Characteristics and Mortality/Morbidity Patient Characteristics in Invasive Pulmonary Aspergillosis ConclusionAlthough IPA is relatively uncommon in patients admitted to the ICU with severe RSV pneumonia, patients with IPA had significant increased LOS and tended to have underlying host factors. Other coinfections with bacterial, viral, and non-IPA fungal pathogens are common in those with severe RSV pneumonia.DisclosuresMichael G. Ison, MD MS, AlloVir (Consultant)

Respiratory syncytial virus infection-induced mucus secretion by down-regulation of miR-34b/c-5p expression in airway epithelial cells.

Severe RSV infection is the main cause of hospitalization to children under the age of five. The regulation of miRNAs on the severity of RSV infection is unclear. The aim of the study was to identify the critical differential expression miRNAs (DE miRNAs) that can regulate the pathological response in RSV‐infected airway epithelial cells. In this study, miRNA and mRNA chips of RSV‐infected airway epithelia from Gene Expression Omnibus (GEO) were screened and analysed, separately. DE miRNAs‐targeted genes were performed for further pathway and process enrichment analysis. DE miRNA‐targeted gene functional network was constructed on the basis of miRNA‐mRNA interaction. The screened critical miRNA was also investigated by bioinformatics analysis. Then, RSV‐infected human bronchial epithelial cells (HBECs) were constructed to verify the expression of the DE miRNAs. Finally, specific synthetic DE miRNAs mimics were used to confirm the effect of DE miRNAs on the RSV‐infected HBECs. 45 DE miRNAs were identified from GEO62306 dataset. Our results showed that hsa‐mir‐34b‐5p and hsa‐mir‐34c‐5p decreased significantly in HBECs after RSV infection. Consistent with the biometric analysis, hsa‐mir‐34b/c‐5p is involved in the regulation of mucin expression gene MUC5AC. In RSV‐infected HBECs, the inducement of MUC5AC production by decreased hsa‐mir‐34b/c‐5p was partly mediated through activation of c‐Jun. These findings provide new insights into the mechanism of mucus obstruction after RSV infection and represent valuable targets for RSV infection and airway obstruction treatment.

Interferon-Induced Protein 44 and Interferon-Induced Protein 44-Like Restrict Replication of Respiratory Syncytial Virus.

Cellular intrinsic immunity, mediated by the expression of an array of interferon-stimulated antiviral genes, is a vital part of host defense. We have previously used a bioinformatic screen to identify two interferon-stimulated genes (ISG) with poorly characterized function, interferon-induced protein 44 (IFI44) and interferon-induced protein 44-like (IFI44L), as potentially being important in respiratory syncytial virus (RSV) infection. Using overexpression systems, CRISPR-Cas9-mediated knockout, and a knockout mouse model, we investigated the antiviral capability of these genes in the control of RSV replication. Overexpression of IFI44 or IFI44L was sufficient to restrict RSV infection at an early time postinfection. Knocking out these genes in mammalian airway epithelial cells increased levels of infection. Both genes express antiproliferative factors that have no effect on RSV attachment but reduce RSV replication in a minigenome assay. The loss of Ifi44 was associated with a more severe infection phenotype in a mouse model of infection. These studies demonstrate a function for IFI44 and IFI44L in controlling RSV infection.IMPORTANCE RSV infects all children under 2 years of age, but only a subset of children get severe disease. We hypothesize that susceptibility to severe RSV necessitating hospitalization in children without predefined risk factors is, in part, mediated at the antiviral gene level. However, there is a large array of antiviral genes, particularly in the ISG family, the mechanism of which is poorly understood. Having previously identified IFI44 and IFI44L as possible genes of interest in a bioinformatic screen, we dissected the function of these two genes in the control of RSV. Through a range of overexpression and knockout studies, we show that the genes are antiviral and antiproliferative. This study is important because IFI44 and IFI44L are upregulated after a wide range of viral infections, and IFI44L can serve as a diagnostic biomarker of viral infection.

ASPERGILLOSIS COMPLICATING SEVERE INFLUENZA AND RSV PNEUMONIA IN ICU PATIENTS: A RETROSPECTIVE COHORT STUDY

Background: Invasive pulmonary aspergillosis (IPA) has been recognized as a complication of influenza infection even in immunocompetent patients. We aimed to understand the incidence of IPA as well as other coinfections over multiple seasons in patients with either severe influenza and RSV pneumonia in the intensive care unit (ICU), with a focus on solid organ transplant (SOT). Materials and Methods: A retrospective cohort study was conducted in a single center in Chicago. Data were collected over six seasons (January 2012 – March 2018) from adult patients admitted to the ICU at a large urban tertiary care center with severe RSV or influenza pneumonia. Patients were included if they had a positive RSV or influenza PCR test, older than 18 years, admitted to the ICU with acute respiratory failure. IPA was defined per both the EORTC/MSG criteria as well as the revised AspICU criteria.[1] Statistics were calculated with Stata 16.0 (StataCorp, TX). Results: Overall the incidence of IPA was low in patients with RSV or influenza (5.5% and 1.7%, respectively). Patients diagnosed with IPA were both predominantly of male sex in both RSV (87.5%, n=7) and influenza (83.3%, n=6) groups. The median overall length of stay was significantly longer in both RSV (23.6 +/- 4.3 d) and influenza (24.6 +/- 3.7 d) groups with IPA. Patients with RSV that developed IPA had significant mortality (62.5%, p=0.01), while patients with influenza did not (33.3%, p=0.11). In patients with SOT, IPA developed in 16.7% (n=1) of SOT patients with influenza, and 12.5% (n=1) with RSV. All SOT patients with IPA had a history of liver transplantation with comorbidities (malignancy, post-op complications) and developed bacterial coinfections. In patients with severe RSV, history of hematological malignancy and neutropenia showed trends towards the development of IPA. In contrast, those with influenza had a history of hematological malignancy (p=0.03), hematopoietic stem cell transplant (p=0.01), non-transplant related immunosuppression (p=0.01), and history of solid organ malignancy (p=0.01) as significant factors associated with IPA. Other coinfections were common with incidences of RSV and influenza groups at bacterial (27.1% v 46.7%), viral (6.9% v 11.7%), and non-aspergillosis fungal (1.3% v 13.3%).Conclusions and Discussion: The incidence of IPA was significantly lower in both RSV and influenza groups in our study (5.5% and 1.7%) than previously reported in similar studies. While RSV-infected patients with IPA had significant mortality, influenza-infected patients did not. SOT itself does not seem to be a significant factor contributing to the development of IPA in the setting of severe viral pneumonia. At the same time, malignancy and profound immunosuppression are factors strongly associated with the development of IPA. Other coinfections with bacterial, viral, and fungal pathogens are common in those with both severe RSV and influenza pneumonia. Reference: 1. Schauwvlieghe A, Rijnders BJA, Philips N, et al. Invasive aspergillosis in patients admitted to the intensive care unit with severe influenza: a retrospective cohort study. Lancet Respir Med 2018;6:782-92.

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

NCT03756766.

Early life RSV infection in neonatal mice leads to exacerbated allergic asthma due to persistent Th2 pulmonary responses that are abrogated by maternal supplementation with a L. johnsonii probiotic

The development of immune responses in infants is central to establishing a balanced system that reacts appropriately to infectious stimuli but does not induce altered disease states with potential long term sequelae. Studies have linked severe RSV infection during early-life with an enhanced likelihood of developing childhood asthma. We have previously shown that supplementing adult mice with a probiotic species identified in allergen-protected animals, L. johnsonii, can attenuate pathologic responses in animals with viral and allergen induced disease. In these studies, we supplemented female mice with L. johnsonii by oral gavage prior to breeding and during pregnancy. The neonatal mice were infected with RSV at day 6 of age after 8 days of infection (day 14) some were evaluated. Subsequently, some of the neonatal miss were sensitized with allergen into the airway 4 or 12 weeks later and examined after a final challenge at 3 weeks post-sensitization. Our studies show that early-life RSV infection leads to long-term effects leaving mice prone to exacerbation upon secondary allergen exposure at 4 to 12 weeks post-infection. Offspring from the L. johnsonii supplemented mice were protected from an early life RSV infection and from the subsequent allergen-induced exacerbated responses. These early life protective responses reduced Th2 responses and mucus and were associated with an altered neonatal microbiome. Using cross-fostering studies we were able to demonstrate both in utero and post natal protective effects on the offspring that were dependent upon the supplementation of the mother with L. johnsonii. Assessment of the plasma and milk metabolic profiles identified an altered metabolite phenotype in the different cross-fostered neonates that may be useful in assessing allergen susceptible and/or protected early immune environments during early life. Thus, we have identified a maternal microbiome associated metabolomic effect associated with protective in offspring that is related to an altered immune phenotype in the lung during RSV infection and subsequent allergic asthma responses. These results identify that maternal environments on offspring have both in utero and post-natal effects and may help guide future clinical research toward evaluating the maternal impact on development of the infant's immune/allergic responses.

Number needed to immunize to prevent RSV with extended half-life monoclonal antibody

BackgroundRespiratory syncytial virus (RSV) is one of the most important respiratory pathogens in young children. Infants <6 months of age and infants and young children with extreme pre-term birth, and cardiac and pulmonary co-morbidities experience the highest incidence of severe RSV disease. There are no licensed vaccines; immunoprophylaxis is recommended for the highest risk children. Extended half-life RSV monoclonal antibodies (EHL-mAbs) are under development intended for immunization of all infants and high-risk children <2 years of age. We modeled the anticipated public health benefits of RSV EHL-mAb immunization using the number needed to immunize (NNI). MethodsWe combined RSV hospitalization, outpatient and outpatient lower respiratory tract infection (LRI) incidence estimates and a range of immunization efficacies to estimate the annual NNI. We calculated the absolute incidence rate reduction (ARR) by multiplying the incidence rates by immunization efficacy. NNI was calculated as the reciprocal of the ARR. ResultsFor an RSV EHL-mAb with 70% efficacy, 6–18 infants would need to be immunized to prevent one RSV-associated outpatient visit, and 13–33 infants would need to be immunized to prevent one RSV-associated LRI outpatient visit. To prevent one RSV-associated hospitalization, 37–85 infants 0–5 months of age, and 107–280 infants 6–11 months of age would need to be immunized. ConclusionsPublic health benefits, such as disease cases averted due to immunization, are essential elements in consideration of candidate vaccines for a national immunization program. An RSV EHL-mAb of moderate efficacy could have high impact. These data provide an additional perspective for public health decision making.

Altered gut microbiota in infants is associated with respiratory syncytial virus disease severity

BackgroundRespiratory syncytial virus (RSV) is the number one cause of lower respiratory tract infections in infants. There are still no vaccines or specific antiviral therapies against RSV, mainly due to the inadequate understanding of RSV pathogenesis. Recent data suggest a role for gut microbiota community structure in determining RSV disease severity. Our objective was to determine the gut microbial profile associated with severe RSV patients, which could be used to help identify at-risk patients and develop therapeutically protective microbial assemblages that may stimulate immuno-protection.ResultsWe enrolled 95 infants from Le Bonheur during the 2014 to 2016 RSV season. Of these, 37 were well-babies and 58 were hospitalized with RSV. Of the RSV infected babies, 53 remained in the pediatric ward (moderate) and 5 were moved to the pediatric intensive care unit at a later date (severe). Stool samples were collected within 72 h of admission; and the composition of gut microbiota was evaluated via 16S sequencing of fecal DNA. There was a significant enrichment in S24_7, Clostridiales, Odoribacteraceae, Lactobacillaceae, and Actinomyces in RSV (moderate and severe) vs. controls. Patients with severe RSV disease had slightly lower alpha diversity (richness and evenness of the bacterial community) of the gut microbiota compared to patients with moderate RSV and healthy controls. Beta diversity (overall microbial composition) was significantly different between all RSV patients (moderate and severe) compared to controls and had significant microbial composition separating all three groups (control, moderate RSV, and severe RSV).ConclusionsCollectively, these data demonstrate that a unique gut microbial profile is associated with RSV disease and with severe RSV disease with admission to the pediatric intensive care unit. More mechanistic experiments are needed to determine whether the differences observed in gut microbiota are the cause or consequences of severe RSV disease.

Respiratory Syncytial Virus Infection Induced Mucus Secretion by Down Regulation of miR-34b/c-5p Expression in Airway Epithelial Cells

Background: Severe RSV infection is the main cause of hospitalization to children under age of five. The regulation of miRNAs on the severity of RSV infection are unclear. The aim of the study is to identify the critical differential expression miRNAs (DE miRNAs) that can regulate the pathological response in RSV-infected airway epithelial cells. Methods: miRNA and mRNA chips of RSV-infected airway epithelia from Gene Expression Omnibus (GEO) was screened and analyzed. DE miRNAs from different groups were identified and performed for further pathway and process enrichment analysis. DE miRNAs-targeted gene functional network was constructed based on miRNA-mRNA interaction. The screened critical miRNA was also investigated by bioinformatics analysis. Then, RSV-infected human bronchial epithelial cells (HBECs) were constructed to verify the expression of the DE miRNAs. Finally, specific synthetic DE miRNAs mimics was used to confirm effect of the DE miRNAs on the of RSV-infected HBECs. Results: 14 DE miRNAs were identified from GEO62306 dataset. Hsa-mir-34b/c-5p decreased significantly in HBECs after RSV infection. Consistent with the biometric analysis, hsa-mir-34b/c-5p is involved in the regulation of mucin expression gene MUC5AC. In RSV-infected HBECs, the inducement of MUC5AC production by decreased hsa-mir-34b/c-5p was partly mediated through activation of c-Jun. Conclusions: We conclude that the decreased expression of hsa-mir-34b/c-5p in HBECs after RSV infection play a critical role in MUC5AC expression through activation of c-Jun. These findings provide new insights into the mechanism of mucus obstruction after RSV infection and represent a useful biomarker of RSV infection and valuable targets of airway obstruction treatment. Funding Statement: This work was funded by grants #81970033，#31900424，#81570026, #81670002 and #3167188 from the NSFC; grants #2017JJ2402, #2019JJ50760 from the Hunan Natural Science Foundation; grant #16K097 from open Foundation of Hunan College Innovation Program and grant #2018zzts813, #2018zzts812, #2019zzts327, #2019zzts1008 from the Fundamental Research Funds for the Central Universities of Central South University. Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: The authors stated: Not applicable.

Respiratory Syncytial Virus-Associated Acute Lower Respiratory Infections in Children With Bronchopulmonary Dysplasia: Systematic Review and Meta-Analysis.

Respiratory syncytial virus (RSV) is among the most important causes of acute lower respiratory tract infection (ALRI) in young children. We assessed the severity of RSV-ALRI in children less than 5 years old with bronchopulmonary dysplasia (BPD). We searched for studies using EMBASE, Global Health, and MEDLINE. We assessed hospitalization risk, intensive care unit (ICU) admission, need for oxygen supplementation and mechanical ventilation, and in-hospital case fatality (hCFR) among children with BPD compared with those without (non-BPD). We compared the (1) length of hospital stay (LOS) and (2) duration of oxygen supplementation and mechanical ventilation between the groups. Twenty-nine studies fulfilled our inclusion criteria. The case definition for BPD varied substantially in the included studies. Risks were higher among children with BPD compared with non-BPD: RSV hospitalization (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.7-4.2; P < .001), ICU admission (OR, 2.9; 95% CI, 2.3-3.5; P < .001), need for oxygen supplementation (OR, 4.2; 95% CI, .5-33.7; P = .175) and mechanical ventilation (OR, 8.2; 95% CI, 7.6-8.9; P < .001), and hCFR (OR, 12.8; 95% CI, 9.4-17.3; P < .001). Median LOS (range) was 7.2 days (4-23) (BPD) compared with 2.5 days (1-30) (non-BPD). Median duration of oxygen supplementation (range) was 5.5 days (0-21) (BPD) compared with 2.0 days (0-26) (non-BPD). The duration of mechanical ventilation was more often longer (>6 days) in those with BPD compared with non-BPD (OR, 11.9; 95% CI, 1.4-100; P = .02). The risk of severe RSV disease is considerably higher among children with BPD. There is an urgent need to establish standardized BPD case definitions, review the RSV prophylaxis guidelines, and encourage more specific studies on RSV infection in BPD patients, including vaccine development and RSV-specific treatment.

79. Mucosal Interferon (IFN) Responses in Infants with Respiratory Syncytial Virus (RSV) Infection to Inform Live Attenuated Vaccine (LAV) Development

BackgroundRespiratory syncytial virus (RSV) is a leading cause of hospitalization for infants. Several vaccine strategies for RSV are being developed. Among those, live attenuated vaccine (LAV) represent an attractive alternative for young children as they mimic natural infection and induce protective immunity without causing enhanced disease. However, markers of reactogenicity and/or innate immune protection in the respiratory mucosa are not well defined. The objective of this study was to assess mucosal markers, including innate immune cytokine profiles and RSV loads (VL), and their potential association with protection from severe disease in infants with natural RSV infection.MethodsSingle-center, prospective study in previously healthy infants with mild (outpatients; OP) and severe (inpatients; IP) RSV infection, and aged-matched healthy controls (HC). Nasopharyngeal (NP) swabs were obtained at enrollment in all subjects to measure VL by PCR, and cytokine concentrations (conc.) using a 13-plex panel that included: Type-I, type-II, and type-III IFN, and inflammatory cytokines. Cytokine conc. and VL were compared according to hospitalization status (OP vs. IP).ResultsFrom 2014 to 2017 we enrolled 105 infants: 48 with severe RSV infection (IP; median IQR age: 2.3 [1.1–5.5] months), 36 with mild disease (OP; 6.4 [3.8–9.3] months), and 20 HC (4.9 [2.8–7.2] months). The median duration of symptoms at enrollment was 4 days for both IP and OP. IL-1β, TNF-α, and IL-10 were detected more frequently in RSV infants than in HC (39% vs. 5%, respectively), but median conc. in IP and OP were not different (P > 0.05). Detection and/or conc. of IFN-β, IP-10, IFN-γ and type III IFN (IFN-λ1, IFN-λ2/3) were significantly greater in OP vs. IP, who also had higher VL (Table 1). In addition, IP-10 (r = 0.6; P < 0.001) and IFN-λ conc. (r = 0.55, P < 0.0001) significantly correlated with RSV VL.ConclusionInfants with mild RSV infection had higher VL and a more robust type-I, -II, and -III IFN responses than those hospitalized with severe disease. These findings suggest that increase conc. of mucosal IFNs are associated with protection against severe RSV infection, and could potentially be used as surrogate markers to help the development of LAV for RSV infection in young children. DisclosuresOctavio Ramilo, MD, Bill & Melinda Gates Foundation: Research Grant; Janssen: Research Grant; Merck: Advisory Board; NIH: Research Grant; Ohio Children’s Hospital Association (OCHA): Research Grant; Pfizer: Advisory Board, Consultant, Lectures; Sanofi/Medimmune: Advisory Board.