Association of Viral Load With Disease Severity in Outpatient Children With Respiratory Syncytial Virus Infection

Novel Approach for Detecting Respiratory Syncytial Virus in Pediatric Patients Using Machine Learning Models Based on Patient-Reported Symptoms: Model Development and Validation Study

BACKGROUND

Respiratory syncytial virus (RSV) affects children, causing serious infections, particularly in high-risk groups. Given the seasonality of RSV and the importance of rapid isolation of infected individuals, there is an urgent need for more efficient diagnostic methods to expedite this process.

OBJECTIVE

This study aimed to investigate the performance of a machine learning model that leverages the temporal diversity of symptom onset for detecting RSV infections and elucidate its discriminatory ability.

METHODS

The study was conducted in pediatric and emergency outpatient settings in Japan. We developed a detection model that remotely confirms RSV infection based on patient-reported symptom information obtained using a structured electronic template incorporating the differential points of skilled pediatricians. An extreme gradient boosting-based machine learning model was developed using the data of 4174 patients aged ≤24 months who underwent RSV rapid antigen testing. These patients visited either the pediatric or emergency department of Yokohama City Municipal Hospital between January 1, 2009, and December 31, 2015. The primary outcome was the diagnostic accuracy of the machine learning model for RSV infection, as determined by rapid antigen testing, measured using the area under the receiver operating characteristic curve. The clinical efficacy was evaluated by calculating the discriminative performance based on the number of days elapsed since the onset of the first symptom and exclusion rates based on thresholds of reasonable sensitivity and specificity.

RESULTS

Our model demonstrated an area under the receiver operating characteristic curve of 0.811 (95% CI 0.784-0.833) with good calibration and 0.746 (95% CI 0.694-0.794) for patients within 3 days of onset. It accurately captured the temporal evolution of symptoms; based on adjusted thresholds equivalent to those of a rapid antigen test, our model predicted that 6.9% (95% CI 5.4%-8.5%) of patients in the entire cohort would be positive and 68.7% (95% CI 65.4%-71.9%) would be negative. Our model could eliminate the need for additional testing in approximately three-quarters of all patients.

CONCLUSIONS

Our model may facilitate the immediate detection of RSV infection in outpatient settings and, potentially, in home environments. This approach could streamline the diagnostic process, reduce discomfort caused by invasive tests in children, and allow rapid implementation of appropriate treatments and isolation at home. The findings underscore the potential of machine learning in augmenting clinical decision-making in the early detection of RSV infection.

Effectiveness of Immunization Products Against Medically Attended Respiratory Syncytial Virus Infection: Generic Protocol for a Test-Negative Case-Control Study

Monitoring the real-life effectiveness of respiratory syncytial virus (RSV) products is of major public health importance. This generic protocol for a test-negative design study aims to address currently envisioned approaches for RSV prevention (monoclonal antibodies and vaccines) to study effectiveness of these products among target groups: children, older adults, and pregnant women. The generic protocol approach was chosen to allow for flexibility in adapting the protocol to a specific setting. This protocol includes severe acute respiratory infection (SARI) and acute respiratory infection (ARI), both due to RSV, as end points. These end points can be applied to studies in hospitals, primarily targeting patients with more severe disease, but also to studies in general practitioner clinics targeting ARI.

Immunogenicity and protective efficacy of an RSV G S177Q central conserved domain nanoparticle vaccine

Introduction

Respiratory syncytial virus (RSV) can cause lower respiratory tract disease in infants and elderly populations. Despite decades of research, there remains no safe and approved RSV vaccine. Previously, we showed that an RSV G glycoprotein subunit vaccine candidate with a single point mutation within the central conserved domain (CCD), i.e. S177Q, considerably improved immunogenicity.

Methods

Here, we examine the development of nanoparticle (NP) vaccines having either an RSV G protein CCD with wild-type sequence (NPWT) or an S177Q mutation (NP-S177Q). The NP vaccine immunogens were adjuvanted with monophosphoryl lipid A (MPLA), a TLR4 agonist to improve Th1- type responses. BALB/c mice were primed with 10 μg of NP-WT vaccine, NPS177Q, or vehicle, rested, and then boosted with a high (25 μg) or low (10 μg) dose of the NP-WT or NP-S177Q homologous candidate and subsequently challenged with RSV A2.

Results

The results showed that mice boosted with NP-S177Q developed superior immunogenicity and neutralizing antibodies compared to NP-WT boosting. IgG from either NP-S177Q or NP-WT vaccinated mice did not interfere with fractalkine (CX3CL1) binding to CX3CR1 and effectively blocked G protein CX3C-CX3CR1 binding. Both NP-WT and NP-S177Q vaccination induced similar neutralizing antibodies to RSV in challenged mice compared to vehicle control. NP-S177Q boosting improved correlates of protection including reduced BAL cell infiltration following RSV challenge. However, the NP vaccine platform will require improvement due to the poor solubility and the unexpectedly weaker Th1-type IgG2a response.

Discussion

The results from this study support further NP-S177Q vaccine candidate development.

Quantifying the effect of defective viral genomes in respiratory syncytial virus infections

Defective viral genomes (DVGs) are viral genomes that contain only a partial viral RNA and so cannot replicate within cells on their own. If a cell containing DVGs is subsequently infected with a complete viral genome, the DVG can then use the missing proteins expressed by the full genome in order to replicate itself. Since the cell is producing defective genomes, it has less resources to produce fully functional virions and thus release of complete virions is often suppressed. Here, we use data from challenge studies of respiratory syncytial virus (RSV) in healthy adults to quantify the effect of DVGs. We use a mathematical model to fit the data, finding that late onset of DVGs and prolonged DVG detection are associated with lower infection rates and higher clearance rates. This result could have implications for the use of DVGs as a therapeutic.

The Contribution of Viruses and Bacteria to Childhood Community-acquired Pneumonia: 11-Year Observational Study From Norway

BACKGROUND

Viruses are associated with pediatric community-acquired pneumonia (CAP) but are also common in the upper airways of healthy children. We have determined the contribution of respiratory viruses and bacteria by comparing children with CAP and hospital controls.

METHODS

Children less than 16 years old with radiologically confirmed CAP (n = 715) were enrolled over an 11-year period. Children admitted for elective surgery during the same period served as controls (n = 673). Nasopharyngeal aspirates were tested for 20 respiratory pathogens by semiquantitative polymerase chain reaction tests and cultivated for bacteria and viruses. We used logistic regression to calculate adjusted odds ratios [aOR; 95% confidence intervals (CIs)], and estimated population-attributable fractions (95% CI).

RESULTS

At least 1 virus was detected in 85% of cases and 76% of controls, and greater than or equal to 1 bacterium was detected in 70% of cases and controls. The presence of respiratory syncytial virus (RSV) (aOR, 16.6; 95% CI: 9.81-28.2), human metapneumovirus (HMPV) (13.0; 6.17-27.5) and Mycoplasma pneumonia e (27.7; 8.37-91.6) were most strongly associated with CAP. For RSV and HMPV, there were significant trends between lower cycle-threshold values indicating higher viral genomic loads, and higher aORs for CAP. The population-attributable fraction estimates of RSV, HMPV, human parainfluenza virus, influenza virus and M. pneumoniae were 33.3% (32.2-34.5), 11.2% (10.5-11.9), 3.7% (1.0-6.3), 2.3% (1.0-3.6) and 4.2% (4.1-4.4), respectively.

CONCLUSIONS

RSV, HMPV and M. pneumoniae were most strongly related to pediatric CAP and accounted for half of all cases. There were positive trends between increasing viral genomic loads of RSV and HMPV, and higher odds for CAP.

Systematic literature review of the signs and symptoms of respiratory syncytial virus

Respiratory syncytial virus (RSV) is responsible for over 30 million lower respiratory tract infections (LRTIs) and 3 million hospitalizations worldwide each year. Despite the risk RSV poses to young children, older adults, and individuals with comorbidities or suppressed immunity, there is limited understanding of RSV symptom presentation across these at-risk groups, and there is no vaccine for RSV. We conducted two systematic literature reviews (SLRs) of studies that document signs and symptoms (S&S) of RSV in (1) children aged ≤5 years and (2) immunocompromised adolescents and adults, and adults at high risk for severe RSV due to age or comorbidities. Symptom duration and hospital length of stay (LOS) were explored. Electronic database searches were performed following PRISMA guidelines. Studies captured RSV S&S across community and hospital settings. Clinicians and caregivers reported (n = 25 studies) nasal discharge/congestion, cough, shortness of breath, feeding abnormalities, and fever in ≥40% of children across studies and settings. Median hospital stays for children ranged from 2 days in the United States to 7.5 days in China. High-risk adults with RSV (n = 6 studies) commonly (≥40% of adults) reported cough, sputum, dyspnea, and fever/feverishness. Median length of hospital stay in adults ranged from 6 to 15 days across studies. Caregivers and clinicians reported similar RSV S&S in young children, including upper and lower respiratory and systemic symptoms. In high-risk and immunocompromised adults, the most frequent (in multiple publications) and commonly reported RSV S&S were primarily LRTI symptoms. RSV symptoms could last for weeks and are variable based on geography.

Association of viral load with TRAIL, IP-10, CRP biomarker signature and disease severity in children with respiratory tract infection or fever without source: A prospective, multicentre cohort study

BACKGROUND

To investigate the association of viral load (VL) with (i) tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), interferon gamma-induced protein-10, C-reactive protein, and a combinatorial score (BV score), and (ii) clinical severity.

STUDY DESIGN

In this prospective, multicentre cohort substudy, children with respiratory tract infection or fever without source were enrolled. VL for influenza virus, rhinovirus, respiratory syncytial virus, and adenovirus was measured from nasopharyngeal swabs. The reference standard diagnosis was established based on expert panel adjudication.

RESULTS

Of 1140 recruited patients, 333 had a virus monodetection. VL for the aggregated data set correlated with TRAIL and IP-10 levels, with the length of oxygen therapy, and inversely with the BV score. At a single viral level, only the influenza VL yielded a correlation with TRAIL, IP-10 levels, and the BV score. Children with a viral reference standard diagnosis had significantly higher VL than those with bacterial infection (p = 0.0005). Low TRAIL (incidence rate ratio [IRR] 0.6, 95% confidence interval [CI] 0.39-0.91) and young age (IRR 0.62, 95% CI 0.49-0.79) were associated with a longer hospital stay, while young age (IRR 0.33, 95% CI 0.18-0.61), low TRAIL (IRR 0.25, 95% CI 0.08-0.76), and high VL (IRR 1.16, 95% CI 1.00-1.33) were predictive of longer oxygen therapy.

CONCLUSION

These findings indicate that VL correlates with biomarkers and may serve as a complementary tool pertaining to disease severity.

Clinical characteristics and illness course based on pathogen among children with respiratory illness presenting to an emergency department

Upper respiratory illnesses due to viruses are the most common reason for pediatric emergency department (ED) visits in the United States. We explored the clinical characteristics, hospitalization risk, and symptom duration of children in an ED setting by respiratory pathogen including coinfections. A retrospective analysis was conducted from a randomized controlled trial evaluating a rapid molecular pathogen panel among 931 children 1 month to 18 years of age with acute respiratory illness. We assessed hospitalization risk by pathogen using multivariable Poisson regression with robust variance. Symptom duration was assessed using multivariable Cox proportional hazards models. Among 931 children, 702 (75%) were aged 0-5 years and 797 (85%) tested positive for a respiratory pathogen. Children with respiratory syncytial virus (RSV), human metapneumovirus (hMPV), and human rhinovirus/enterovirus (HRV/EV) had higher hospitalization risk compared with influenza (adjusted risk ratio [aRR]: 2.95, 95% confidence interval [CI]: 1.17-7.45; 3.56, 95% CI: 1.05-12.02; aRR: 2.58, 95% CI: 1.05-6.35, respectively). Children with RSV, parainfluenza and atypical bacterial pathogens had longer illness duration compared with influenza (adjusted hazards ratio [aHR]: 2.16 95% CI: 1.41-3.29; aHR: 1.67, 95% CI:1.06-2.64; aHR: 2.60 95% CI: 1.30-5.19, respectively). Children with RSV, hMPV, and atypical bacterial pathogens had higher illness severity and duration compared with other respiratory pathogens. Coinfection was not associated with increased illness severity.

Cepheid Xpert Xpress Flu/RSV evaluation performed by minimally trained non-laboratory operators in a CLIA-waived environment

The COVID-19 pandemic highlighted the significance of readily available and easily performed viral testing for surveillance during future infectious pandemics. The objectives of this study were: to assess the performance of the Xpert Xpress Flu and/or RSV test, a multiplex PCR assay for detecting influenza A and B virus and respiratory syncytial virus nucleic acids in respiratory tract specimens, relative to the Quidel Lyra Influenza A+B assay and the Prodesse ProFlu+ assay, and the system's ease of use by minimally trained operators. Overall, the Xpert Xpress Flu/RSV test demonstrated a high positive and negative percent agreement with the comparator assays, and was easy to use and interpret results, based on the operators’ feedback. We concluded that the Xpert Xpress Flu/RSV test is sensitive, specific, and easy to use for the diagnosis of influenza and RSV by minimally trained operators and can be a valuable tool in future infectious clusters or pandemics.

Clinical Burden of Respiratory Syncytial Virus in Hospitalized Children Aged ≤5 years (INSPIRE Study)

Background

Respiratory syncytial virus (RSV) is a leading cause of hospitalizations in children (≤5 years of age); limited data compare burden by age.

Methods

This single-center retrospective study included children (≤5 years of age) hospitalized for >24 hours with reverse-transcription polymerase chain reaction (RT-PCR)–confirmed RSV infection (2015–2018). Hospital length of stay (LOS), intensive care unit (ICU) admissions, ICU LOS, supplemental oxygen, and medication use were assessed. Multivariate logistic regression analyses identified predictors of hospital LOS >5 days.

Results

Three hundred twelve patients had RSV infection (ages 0 to <6 months [35%], 6 to <12 months [15%], 1 to <2 years [25%], and 2–5 years [25%]); 16.3% had predefined comorbidities (excludes preterm infants). Median hospital LOS was 5.0 days and similar across age; 5.1% (16/312) were admitted to ICU (ICU LOS, 5.0 days), with those aged 0 to <6 months admitted most frequently (10/108 [9.3%]). Supplemental oxygen was administered in 57.7% of patients, with similar need across ages. Antibiotics were administered frequently during hospitalization (43.6%). Predictors of prolonged LOS included pneumonia (odds ratio [OR], 2.33), supplemental oxygen need (OR, 5.09), and preterm births (OR, 3.37). High viral load (RT-PCR RSV cycle threshold value <25) was associated with greater need for supplemental oxygen.

Conclusions

RSV causes substantial burden in hospitalized children (≤5 years), particularly preterm infants and those aged <6 months.

A study of the effects of age on the dynamics of RSV in animal models

Respiratory syncytial virus can cause severe illness and even death, particularly in infants. The increased severity of disease in young children is thought to be due to a lack of previous exposure to the virus as well as the limited immune response in infants. While studies have examined the clinical differences in disease between infants and adults, there has been limited examination of how the viral dynamics differ as infants develop. In this study, we apply a mathematical model to data from cotton rats and ferrets of different ages to assess how viral kinetics parameters change as the animals age. We find no clear trend in the viral decay rate, infecting time, and basic reproduction number as the animals age. We discuss possible reasons for the null result including the limited data, lack of detail of the mathematical model, and the limitations of animal models.

Epidemiology of respiratory syncytial virus in a community birth cohort of infants in the first 2 years of life

Respiratory syncytial virus (RSV) is the most common virus identified in children hospitalised with acute respiratory infections. However, less is known about RSV in community settings. This report describes RSV epidemiology in the community, including acute illness episodes, healthcare burden, and risk factors in Australian children during the first 2-years of life. A community-based, birth cohort from Brisbane, Australia, followed children until their second birthday. Parents completed daily respiratory symptom and illness-burden diaries. Weekly parent-collected nasal swabs were analysed for RSV by real-time polymerase chain reaction assays. Serum RSV-neutralising antibodies were assayed at age 3 years. Overall, 158 children provided 11,216 swabs, of which 104 were RSV-positive (85 incident episodes). RSV incidence in the first 2 years of life was 0.46 (95% CI = 0.37-0.58) episodes per child-year. Incidence increased with age and formal childcare attendance and was highest in autumn. Of 82 episodes linked with symptom data, 60 (73.2%) were symptomatic, 28 (34.1%) received community-based medical care, and 2 (2.4%) led to hospitalisation. Viral load was higher in symptomatic than asymptomatic infections. In 72 children, RSV-specific antibody seroprevalence was 94.4% at age 3 years.Conclusion: RSV incidence increased after age 6-months with approximately three-quarters of infections symptomatic and most infections treated in the community. What is known •RSV is a major cause of hospitalisation for acute lower respiratory infections in infants and young children, especially in the first 6 months of life. •However, limited data exist on the overall burden in young children at the community level. What is new •RSV incidence in the community increases after age 6 months, and by 3 years, most children have been infected. •About one-quarter of RSV infections were asymptomatic in children aged < 2 years, and approximately 60% of children with RSV-related symptoms had a healthcare contact of any kind with most managed within the community.

Detection of respiratory syncytial virus defective genomes in nasal secretions is associated with distinct clinical outcomes

Respiratory syncytial virus (RSV) causes respiratory illness in children, immunosuppressed individuals and the elderly. However, the viral factors influencing the clinical outcome of RSV infections remain poorly defined. Defective viral genomes (DVGs) can suppress virus replication by competing for viral proteins and by stimulating antiviral immunity. We studied the association between detection of DVGs of the copy-back type and disease severity in three RSV A-confirmed cohorts. In hospitalized children, detection of DVGs in respiratory samples at or around the time of admission associated strongly with more severe disease, higher viral load and a stronger pro-inflammatory response. Interestingly, in experimentally infected adults, the presence of DVGs in respiratory secretions differentially associated with RSV disease severity depending on when DVGs were detected. Detection of DVGs early after infection associated with low viral loads and mild disease, whereas detection of DVGs late after infection, especially if DVGs were present for prolonged periods, associated with high viral loads and severe disease. Taken together, we demonstrate that the kinetics of DVG accumulation and duration could predict clinical outcome of RSV A infection in humans, and thus could be used as a prognostic tool to identify patients at risk of worse clinical disease.

Engineering Protease-Resistant Peptides to Inhibit Human Parainfluenza Viral Respiratory Infection

The lower respiratory tract infections affecting children worldwide are in large part caused by the parainfluenza viruses (HPIVs), particularly HPIV3, along with human metapneumovirus and respiratory syncytial virus, enveloped negative-strand RNA viruses. There are no vaccines for these important human pathogens, and existing treatments have limited or no efficacy. Infection by HPIV is initiated by viral glycoprotein-mediated fusion between viral and host cell membranes. A viral fusion protein (F), once activated in proximity to a target cell, undergoes a series of conformational changes that first extend the trimer subunits to allow insertion of the hydrophobic domains into the target cell membrane and then refold the trimer into a stable postfusion state, driving the merger of the viral and host cell membranes. Lipopeptides derived from the C-terminal heptad repeat (HRC) domain of HPIV3 F inhibit infection by interfering with the structural transitions of the trimeric F assembly. Clinical application of this strategy, however, requires improving the in vivo stability of antiviral peptides. We show that the HRC peptide backbone can be modified via partial replacement of α-amino acid residues with β-amino acid residues to generate α/β-peptides that retain antiviral activity but are poor protease substrates. Relative to a conventional α-lipopeptide, our best α/β-lipopeptide exhibits improved persistence in vivo and improved anti-HPIV3 antiviral activity in animals.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Burden of Respiratory Syncytial Virus Infection During the First Year of Life

BACKGROUND

Although many infants with respiratory syncytial virus (RSV) infection are hospitalized, most infants are treated as outpatients. Limited data are available on the burden of RSV in outpatient infants.

METHODS

In a prospective study, we enrolled 431 newborn infants and followed them up for a 10-month period (September-June). During each respiratory illness, we examined the infants and obtained nasopharyngeal specimens for the detection of RSV. The parents completed daily symptom diaries throughout the study.

RESULTS

Among 408 active participants, the seasonal incidence rate of RSV illness was 328.4 per 1000 (95% confidence interval [CI], 275.2-389.0). Infants with ≥1 sibling had a 1.9-fold higher incidence of RSV illness than those without siblings (95% CI, 1.3-2.8; P < .001). Acute otitis media developed in 103 (76.9%) of 134 infants with RSV infection, and 95 (70.9%) were treated with antibiotics. Nine infants with RSV (6.7%) were hospitalized, for a seasonal incidence rate of RSV hospitalization of 22.1 per 1000 (95% CI, 10.1-41.9).

CONCLUSIONS

The outpatient burden of RSV is heavy on infants during the first year of life. Acute otitis media is a frequent complication of RSV, and it should be included in cost-effectiveness analyses of prevention or treatment of RSV infections in infants.

Neutrophils in respiratory syncytial virus infection: From harmful effects to therapeutic opportunities

Respiratory syncytial virus (RSV) is an important infectious agent in infants and young children. In most cases, RSV infection only causes mild disease, but in some, it requires invasive ventilation. Although antiviral drugs are obvious candidates to treat viral illness, and some have shown antiviral effects in humans, antivirals such as GS-5806, ALX-0171 and ALS-8176 have not yet met their expectations. Since the inappropriate or dysregulated immune response against RSV leads to harmful immune pathology, a robust immune cascade is probably underway by the time patients reach the hospital. RSV infection is associated with a strong neutrophil influx into the airway. It not clear if these cells contribute to antiviral defence or to lung pathology. This article discusses the protective and harmful roles of neutrophils during RSV infection and provides an overview of mechanisms by which neutrophil function could be targeted to prevent tissue injury and preserve homeostasis.

Challenges in the prevention or treatment of RSV with emerging new agents in children from low- and middle-income countries

INTRODUCTION

Respiratory syncytial virus (RSV) causes approximately 120,000 deaths annually in children <5 years, with 99% of fatalities occurring in low- and middle-income countries (LMICs).

AREAS COVERED

There are numerous RSV interventions in development, including long-acting monoclonal antibodies, vaccines (maternal and child) and treatments which are expected to become available soon. We reviewed the key challenges and issues that need to be addressed to maximize the impact of these interventions in LMICs. The epidemiology of RSV in LMICs was reviewed (PubMed search to 30 June 2020 inclusive) and the need for more and better-quality data, encompassing hospital admissions, community contacts, and longer-term respiratory morbidity, emphasized. The requirement for an agreed clinical definition of RSV lower respiratory tract infection was proposed. The pros and cons of the new RSV interventions are reviewed from the perspective of LMICs.

EXPERT OPINION

We believe that a vaccine (or combination of vaccines, if practicable) is the only viable solution to the burden of RSV in LMICs. A coordinated program, analogous to that with polio, involving governments, non-governmental organizations, the World Health Organization, the manufacturers and the healthcare community is required to realize the full potential of vaccine(s) and end the devastation of RSV in LMICs.

Safety and Antiviral Effects of Nebulized PC786 in a Respiratory Syncytial Virus Challenge Study

Background

PC786 is a nebulized nonnucleoside respiratory syncytial virus (RSV) polymerase inhibitor designed to treat RSV, which replicates in the superficial layer of epithelial cells lining the airways.

Methods

Fifty-six healthy volunteers inoculated with RSV-A (Memphis 37b) were randomly dosed with either nebulized PC786 (5 mg) or placebo, twice daily for 5 days, from either 12 hours after confirmation of RSV infection or 6 days after virus inoculation. Viral load (VL), disease severity, pharmacokinetics, and safety were assessed until discharge. RSV infection was confirmed by reverse-transcription quantitative polymerase chain reaction with any positive value (intention-to-treat infected [ITT-I] population) or RSV RNA ≥1 log₁₀ plaque-forming unit equivalents (PFUe)/mL (specific intention-to-treat infection [ITT-IS] population) in nasal wash samples.

Results

In the ITT-I population, the mean VL area under the curve (AUC) was lower in the PC786 group than the placebo group (274.1 vs 406.6 log₁₀ PFUe/mL × hour; P = .0359). PC786 showed a trend toward reduction of symptom score and mucous weight. In ITT-IS (post hoc analysis), the latter was statistically significant as well as VL AUC (P = .0126). PC786 showed an early time to maximum plasma concentration, limited systemic exposure, and long half-life and consequently a 2-fold accumulation over the 5-day dosing period. PC786 was well tolerated.

Conclusions

Nebulized PC786 demonstrated a significant antiviral effect against RSV, warranting further clinical study.

Clinical Trials Registration

ClinicalTrials.gov: NCT03382431; EudraCT: 2017-002563-18.

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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

FUNDING

Ablynx, a Sanofi Company.

The effectiveness and safety of Tanreqing Injection combined with ganciclovir on the treatment of respiratory syncytial virus pneumonia in children: A protocol for systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Based on the Theory of Traditional Chinese Medicine, this study systematically evaluated the effectiveness and safety of Chinese medicine preparation Tanreqing injection combined with ganciclovir on the treatment of respiratory syncytial virus pneumonia in children, and provided new ideas and methods for the treatment of respiratory syncytial virus pneumonia (RSVP) in children. At the same time, it also studies the effectiveness and safety of the combination of Chinese and Western medicine on the treatment of related diseases from the direction of evidence-based medicine.

METHODS

The relevant literature was searched by the computer in the electronic network databases, the retrieved databases include Chinese database and English database, English database includes PubMed, Cochrane Library, Embase and Web of Science. Chinese database includes: CNKI, SinoMed, WangFang Date, VIP and other networks electronic full-text database, conducting a randomized controlled trial of Tanreqing Injection combined with ganciclovir (study group) and ganciclovir alone (control group) on the treatment of RSVP in children and the retrieval time limit is set from the establishment of each database to July 1, 2020. According to the inclusion and exclusion criteria, the literature is independently searched and screened by 2 researchers, and conducting the full-text retrieval and evaluation of the research to be included, and extracting the information and checking it after reading the full-text; In case of disagreement, a third researcher will be invited to participate, and the decision is made after discussion by the 3 researchers. They were using the bias risk assessment tool provided by the Cochrane Handbook for Systematic Reviews of Interventions 3.0.2 to evaluate the selected literature. They were using RevMan 5.3 statistical software to conduct statistical analysis.

RESULTS

This study will be carried out in full accordance with the steps of systematic review as required in the Cochrane Handbook for Systematic Reviews of Interventions. All research results will be published publicly in international academic journals with peer review.

CONCLUSION

After the meta-analysis of Tanreqing injection combined with ganciclovir on the treatment of RSVP in children, this paper will give a scientific and objective judgment on the effectiveness and safety of the combined use of Chinese and Western medicine on the treatment of RSVP in children, to provide evidence-based medical evidence for the clinical application, effectiveness and safety of Chinese and Western medicine combined on the treatment of RSVP in children.

PROSPERO REGISTRATION NUMBER

OSF platform, registration number: j2bz5.