The 2009 COID recommendations for RSV prophylaxis: issues of efficacy, cost, and evidence-based medicine

Palivizumab prophylaxis against respiratory syncytial virus infection in patients younger than 2 years of age with congenital heart disease

BACKGROUND

Respiratory syncytial virus (RSV) is a viral pathogen that causes annual epidemics of lower respiratory tract infection with substantial morbidity and mortality in young children, especially those with congenital heart disease (CHD). Palivizumab is the only immunoprophylaxis therapy approved for RSV infection in infants with hemodynamically significant acyanotic or cyanotic CHD.

OBJECTIVE

Identify the compliance rate with vaccination and study the effect of RSV vaccination on hospital admissions.

DESIGN

Retrospective descriptive study.

SETTING

Cardiac center.

PATIENTS AND METHODS

Patient data was obtained from outpatient clinic records, inpatient records, and a surgical database for the period from October 2010 to March 2016. Infants with hemodynamically significant CHD, cyanotic CHD and moderate-to-severe pulmonary hypertension were included in the study. Palivizumab 15/mg/kg was given monthly starting from October, the usual beginning of the epidemic season, with five doses in the first season and six doses in the remaining season scheduled for administration. Patients were interviewed at every clinic visit for any side effects during the previous month, occurrence of any RSV infection and any hospital admission. Selection criteria included RSV vaccination and absence of RSV disease. Patients were excluded if they had RSV infection or a repaired cardiac lesion.

MAIN OUTCOME MEASURES

Compliance rate, hospital admission frequency and period of stay.

SAMPLE SIZE

530 during six seasons of RSV epidemics.

RESULTS

Fourteen patients (2.6%) developed RSV infection and 13 (2.5%) required hospital admission, but only one patient (0.1%) needed intensive care admission. There were no deaths related to RSV infection; however 11 patients died due to causes unrelated to RSV infection. The average compliance rate was 97%.

CONCLUSION

Palivizumab was well tolerated and effective in the prophylaxis of severe RSV infection in children with CHD. As in other studies of palivizumab prophylaxis, we observed a reduction in hospital admissions.

LIMITATIONS

Retrospective design.

CONFLICT OF INTEREST

None.

The antiviral effects of RSV fusion inhibitor, MDT-637, on clinical isolates, vs its achievable concentrations in the human respiratory tract and comparison to ribavirin

Background

Respiratory syncytial virus (RSV) viral load and disease severity associate, and the timing of viral load and disease run in parallel. An antiviral must be broadly effective against the natural spectrum of RSV genotypes and must attain concentrations capable of inhibiting viral replication within the human respiratory tract.

Objectives

We evaluated a novel RSV fusion inhibitor, MDT‐637, and compared it with ribavirin for therapeutic effect in vitro to identify relative therapeutic doses achievable in humans.

Method

MDT‐637 and ribavirin were co‐incubated with RSV in HEp‐2 cells. Quantitative PCR assessed viral concentrations; 50% inhibitory concentrations (IC₅₀) were compared to achievable human MDT‐637 and ribavirin peak and trough concentrations.

Results and conclusions

The IC₅₀ for MDT‐637 and ribavirin (against RSV‐A Long) was 1.42 and 16 973 ng/mL, respectively. The ratio of achievable peak respiratory secretion concentration to IC₅₀ was 6041‐fold for MDT‐637 and 25‐fold for aerosolized ribavirin. The ratio of trough concentration to IC₅₀ was 1481‐fold for MDT‐637 and 3.29‐fold for aerosolized ribavirin. Maximal peak and trough levels of oral or intravenous ribavirin were significantly lower than their IC₅₀s. We also measured MDT‐637 IC₅₀s in 3 lab strains and 4 clinical strains. The IC₅₀s ranged from 0.36 to 3.4 ng/mL. Achievable human MDT‐637 concentrations in respiratory secretions exceed the IC₅₀s by factors from hundreds to thousands of times greater than does ribavirin. Furthermore, MDT‐637 has broad in vitro antiviral activity on clinical strains of different RSV genotypes and clades. Together, these data imply that MDT‐637 may produce a superior clinical effect compared to ribavirin on natural RSV infections.

Update on the use of immunoglobulin in human disease: A review of evidence

Human immunoglobulin preparations for intravenous or subcutaneous administration are the cornerstone of treatment in patients with primary immunodeficiency diseases affecting the humoral immune system. Intravenous preparations have a number of important uses in the treatment of other diseases in humans as well, some for which acceptable treatment alternatives do not exist. We provide an update of the evidence-based guideline on immunoglobulin therapy, last published in 2006. Given the potential risks and inherent scarcity of human immunoglobulin, careful consideration of its indications and administration is warranted.

Detection of common respiratory viruses in tonsillar tissue of children with obstructive sleep apnea

BACKGROUND

Early life viral infection is associated with neurogenic inflammation that is present in lymphoid tissues of the upper airway in children with obstructive sleep apnea (OSA). We hypothesized that viral genomic material is present in tonsils of children with OSA. Therefore, we examined tonsils for the presence of respiratory viruses' nucleic acids in children with OSA, and in children without OSA (undergoing surgery for recurrent throat infections (RI)).

METHODS

Tonsillar tissue from patients with OSA and RI was subjected to multiplex quantitative real time reverse transcription PCR (mqRTPCR), analyzed for the presence of common respiratory viruses' genetic material.

RESULTS

Fifty-six patients were included, of whom 34 had OSA (age (years ± S.D), 4.22 ± 1.14) and 22 with RI (4.35 ± 1.36). Respiratory viruses nucleic acids (24 detections) were observed in 17 (50%) OSA samples. In contrast, no virus was detected in RI samples (relative frequency P<0.0001). Viruses detected, based on frequency were Rhinovirus, Adenovirus, human metapneumovirus (hMPV), respiratory syncytial virus (RSV), and corona virus.

CONCLUSIONS

Respiratory viruses are detected in OSA hypertrophic tonsils, suggestive of their role in the evolution of tonsillar inflammation and hypertrophy. Early life viral infections may contribute to the pathogenesis of pediatric OSA.

Updated guidance for palivizumab prophylaxis among infants and young children at increased risk of hospitalization for respiratory syncytial virus infection

Guidance from the American Academy of Pediatrics (AAP) for the use of palivizumab prophylaxis against respiratory syncytial virus (RSV) was first published in a policy statement in 1998. Guidance initially was based on the result from a single randomized, placebo-controlled clinical trial conducted in 1996-1997 describing an overall reduction in RSV hospitalization rate from 10.6% among placebo recipients to 4.8% among children who received prophylaxis. The results of a second randomized, placebo-controlled trial of children with hemodynamically significant heart disease were published in 2003 and revealed a reduction in RSV hospitalization rate from 9.7% in control subjects to 5.3% among prophylaxis recipients. Because no additional controlled trials regarding efficacy were published, AAP guidance has been updated periodically to reflect the most recent literature regarding children at greatest risk of severe disease. Since the last update in 2012, new data have become available regarding the seasonality of RSV circulation, palivizumab pharmacokinetics, the changing incidence of bronchiolitis hospitalizations, the effects of gestational age and other risk factors on RSV hospitalization rates, the mortality of children hospitalized with RSV infection, and the effect of prophylaxis on wheezing and palivizumab-resistant RSV isolates. These data enable further refinement of AAP guidance to most clearly focus on those children at greatest risk.

Prevention and prophylaxis of respiratory syncytial virus in pediatric cardiology: a UK perspective

ABSTRACT: 

Respiratory syncytial virus (RSV) is a common infection, causing bronchiolitis in over 70% of infants each year and almost all children by the age of 2. It is the leading cause of acute lower respiratory tract infections and admissions to hospital worldwide. Previously healthy infants may have a prolonged cough or wheezing following RSV infection but up to 20% of those with congenital cardiac disease will be hospitalized and have significant morbidity and mortality. For this reason, it is generally recommended that many such infants should receive prophylaxis against RSV infection with palivizumab. This paper reviews the current state of knowledge about RSV affecting children with congenital heart disease from the perspective of those living in the UK and the current protection offered to such children. We also discuss the plans for the future of protection against RSV.

Prebiotic and probiotic supplementation prevents rhinovirus infections in preterm infants: a randomized, placebo-controlled trial

Background

Simple and safe strategies for the prevention of viral respiratory tract infections (RTIs) are needed.

Objective

We hypothesized that early prebiotic or probiotic supplementation would reduce the risk of virus-associated RTIs during the first year of life in a cohort of preterm infants.

Methods

In this randomized, double-blind, placebo-controlled trial (ClinicalTrials.gov no. NCT00167700), 94 preterm infants (gestational age, ≥32 + 0 and ≤36 + 6 weeks; birth weight, >1500 g) treated at Turku University Hospital, Turku, Finland, were allocated to receive oral prebiotics (galacto-oligosaccharide and polydextrose mixture, 1:1), a probiotic (Lactobacillus rhamnosus GG, ATCC 53103), or placebo (microcrystalline cellulose) between days 3 and 60 of life. The primary outcome was the incidence of clinically defined virus-associated RTI episodes confirmed from nasal swabs by using nucleic acid testing. Secondary outcomes were the severity and duration of RTIs.

Results

A significantly lower incidence of RTIs was detected in infants receiving prebiotics (rate ratio [RR], 0.24; 95% CI, 0.12-0.49; P < .001) or probiotics (RR, 0.50; 95% CI, 0.28-0.90; P = .022) compared with those receiving placebo. Also, the incidence of rhinovirus-induced episodes, which comprised 80% of all RTI episodes, was found to be significantly lower in the prebiotic (RR, 0.31; 95% CI, 0.14-0.66; P = .003) and probiotic (RR, 0.49; 95% CI, 0.24-1.00; P = .051) groups compared with the placebo group. No differences emerged among the study groups in rhinovirus RNA load during infections, duration of rhinovirus RNA shedding, duration or severity of rhinovirus infections, or occurrence of rhinovirus RNA in asymptomatic infants.

Conclusions

Gut microbiota modification with specific prebiotics and probiotics might offer a novel and cost-effective means to reduce the risk of rhinovirus infections.

Prevalence of respiratory syncytial virus-associated lower respiratory infection and apnea in infants presenting to the emergency department

The prevalence of respiratory syncytial virus in children presenting to US emergency departments with lower respiratory tract infection or apnea (N = 4172) was evaluated outside the traditional respiratory syncytial virus season (September to October and April to May) relative to January to February. The Mid-Atlantic and Southeast demonstrated positivity rates in September to October comparable with rates observed during January to February.

Prospective validation of a prognostic model for respiratory syncytial virus bronchiolitis in late preterm infants: a multicenter birth cohort study

OBJECTIVES

This study aimed to update and validate a prediction rule for respiratory syncytial virus (RSV) hospitalization in preterm infants 33-35 weeks gestational age (WGA).

STUDY DESIGN

The RISK study consisted of 2 multicenter prospective birth cohorts in 41 hospitals. Risk factors were assessed at birth among healthy preterm infants 33-35 WGA. All hospitalizations for respiratory tract infection were screened for proven RSV infection by immunofluorescence or polymerase chain reaction. Multivariate logistic regression analysis was used to update an existing prediction model in the derivation cohort (n = 1,227). In the validation cohort (n = 1,194), predicted versus actual RSV hospitalization rates were compared to determine validity of the model.

RESULTS

RSV hospitalization risk in both cohorts was comparable (5.7% versus 4.9%). In the derivation cohort, a prediction rule to determine probability of RSV hospitalization was developed using 4 predictors: family atopy (OR 1.9; 95%CI, 1.1-3.2), birth period (OR 2.6; 1.6-4.2), breastfeeding (OR 1.7; 1.0-2.7) and siblings or daycare attendance (OR 4.7; 1.7-13.1). The model showed good discrimination (c-statistic 0.703; 0.64-0.76, 0.702 after bootstrapping). External validation showed good discrimination and calibration (c-statistic 0.678; 0.61-0.74).

CONCLUSIONS

Our prospectively validated prediction rule identifies infants at increased RSV hospitalization risk, who may benefit from targeted preventive interventions. This prediction rule can facilitate country-specific, cost-effective use of RSV prophylaxis in late preterm infants.

Prevalence and Characteristics of Human Metapneumovirus Infection Among Hospitalized Children at High Risk for Severe Lower Respiratory Tract Infection

BACKGROUND

Human metapneumovirus (HMPV) is a significant cause of respiratory tract infections. Little is known about HMPV in children who are at high risk for lower respiratory tract infection (LRTI).

METHODS

To determine the prevalence of HMPV in high-risk children and to identify HMPV risk factors, children ≤24 months with prematurity, chronic lung disease, and/or congenital cardiac disease who were hospitalized with LRTI were prospectively enrolled. Nasopharyngeal aspirates were tested for HMPV, respiratory syncytial virus (RSV), influenza A and B, and parainfluenza types 1-3. Demographics, medical history, and outcomes for those with HMPV and RSV were compared. A multivariate analysis was performed to determine HMPV risk factors.

RESULTS

Over 4 years, 1126 eligible children were enrolled. Pathogens were identified in 61% of subjects. HMPV was identified in 9.0%, second to RSV (45%). Coinfection with HMPV and RSV occurred in <1% of subjects. Subjects infected with HMPV were older (8.2 vs 4.0 months, P < .001), were born more prematurely (27 vs 33 weeks, P < .001), and more commonly had chronic lung disease (59.3% vs 21.8%, P < .001) compared with subjects infected with RSV. In a multivariate analysis that compared children infected with HMPV to all others, increasing age and household exposure to children ages 6-12 were associated with an increased risk, whereas birth at older gestational age and exposure to children age >12 were associated with a decreased risk.

CONCLUSIONS

HMPV was detected in 9% of high-risk children who were hospitalized with lower respiratory tract disease, representing the second most common virus in this population. Compared with all other subjects (including RSV-infected), subjects infected with HMPV were older but were born more prematurely.

Use of palivizumab in primary practice

OBJECTIVE

To describe the implementation of a program for the use of palivizumab in a general pediatrics office and evaluate adherence to the 2009 American Academy of Pediatrics (AAP) guidelines.

METHODS

Pediatricians in a large practice were educated in the diagnosis and management of bronchiolitis, with specific attention to the AAP's palivizumab administration guidelines. During the 2009-2010 and 2010-2011 respiratory syncytial virus seasons, children were systematically identified and enrolled for palivizumab administration. Indication for administration was determined by gestational age, age at the beginning of the respiratory syncytial virus season, pertinent diagnoses, and presence of risk factors.

RESULTS

In the 2009-2010 season, 161 children were enrolled to receive palivizumab, 86 of whom (53%) conformed with AAP guidelines. In contrast, in 2010-2011, a total of 85 children were enrolled to receive palivizumab, and 73 (86%) conformed with the guidelines. As a consequence, the total cost of palivizumab (US $: 511 559 vs 1 500 670) and the cost per child (US $: 6018 vs 9438) were lower in 2010-2011 than in 2009-2010. However, of the children selected within the AAP guidelines, only 29% received the appropriate number of doses, whereas 62% and 9% received fewer or excessive doses, respectively; these findings were similar for the 2 seasons.

CONCLUSIONS

In a primary practice, use of palivizumab outside of the AAP guidelines was frequent and manifested as inadequate indications or inadequate number of doses. The former improved with education and standardization of care (suggesting provider problems), while the latter did not (suggesting system problems). Additional interventions are required.

A review of palivizumab and emerging therapies for respiratory syncytial virus

INTRODUCTION

Respiratory syncytial virus (RSV) is an important pathogen in children and adults; however, current treatment options are primarily supportive. Palivizumab, the only approved specific monoclonal antibody for RSV is used prophylactically to reduce morbidity in a select population of high-risk children.

AREAS COVERED

The development and current use of palivizumab; the potential role of palivizumab as preventive therapy in patients with cystic fibrosis, asthma and compromised immune systems; and explores the limited research in which palivizumab has been used for treatment of RSV. The modified recommendations for the use of palivizumab espoused by the American Academy of Pediatrics and research on the cost-effectiveness of this product are presented. In addition, the authors discuss the development of enhanced monoclonal antibodies including motavizumab, which was recently denied FDA approval for preventative therapy. The authors explore the historical and current efforts to develop a vaccine targeting RSV. The current status of antiviral drug development is also reviewed. The literature search included RSV-Ig, palivizumab, and emerging drugs and vaccines for the treatment of RSV as keywords and titles from 1997 to 2011.

EXPERT OPINION

Although there are potential drugs and vaccines in development to prevent or reduce the effects of RSV infection, palivizumab remains the only licensed product to reduce the severity of disease in high-risk pediatric patients.

Respiratory syncytial virus disease: update on treatment and prevention

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections in infants and young children, accounting for more than 100,000 hospitalizations per year in the USA. The majority of hospitalizations occur in infants less than 1 year of age. Worldwide, RSV is associated with an annual mortality rate of 160,000-600,000 deaths. Premature infants, and infants with congenital heart disease, neuromuscular disease, structural airway abnormalities and immunodeficiencies are at increased risk for severe RSV disease. Despite the magnitude of RSV disease, treatment remains primarily supportive. Trials of bronchodilators, corticosteroids and montelukast have not demonstrated conclusive clinical benefit. The antiviral drug ribavirin has demonstrated only marginal clinical benefit and is not routinely indicated in treatment of RSV disease. Palivizumab is beneficial in prophylaxis for infants at high-risk for severe RSV infection although optimal indications based on cost-effectiveness considerations have not been defined. Future directions in treatment and prevention of RSV infections likely include the second-generation monoclonal antibody motavizumab, more potent antiviral compounds and more unique anti-inflammatory agents. Vaccination against RSV is in development but not eminent.

Preterm birth and respiratory disease in later life

Chronic respiratory diseases are a common complication of preterm birth, particularly among very immature infants or those suffering from bronchopulmonary dysplasia. Major progress in the treatment of preterm newborns has changed the pattern of late respiratory complications. The major respiratory problem in infancy and early childhood is respiratory exacerbations caused by infections (particularly viral ones), which need hospitalization. The symptoms become mild in school-age children; however, a group of children still present with chronic airway obstruction defined by recurrent episodes of wheezing and decreased lung function tests (decreased forced expiratory volume). For some preterm infants, particularly those with bronchopulmonary dysplasia, obstructive lung disease persists into adulthood. They are very likely to develop chronic obstructive pulmonary disease or similar disease later in life. In these patients, a program of lung function monitoring and pulmonary prophylaxis by means of elimination of specific risk factors in adulthood is advisable.

Contributions of humoral and cellular immunity to vaccine-induced protection in humans

Vaccines play a vital role in protecting the host against infectious disease. The most effective licensed vaccines elicit long-term antigen-specific antibody responses by plasma cells in addition to the development of persisting T cell and B cell memory. The relative contributions of these different immune cell subsets are context-dependent and vary depending on the attributes of the vaccine (i.e., live/attenuated, inactivated, and subunit) as well as the biology of the pathogen in question. For relatively simple vaccines against bacterial antigens (e.g., tetanus toxin) or invariant viruses, the immunological correlates of protection are well-characterized. For more complex vaccines against viruses, especially those that mutate or cause latent infections, it is more difficult to define the specific correlates of immunity. This often requires observational/natural history studies, clinical trials, or experimental evaluation in relevant animal models in order for immunological correlates to be determined or extrapolated. In this review, we will discuss the relative contributions of virus-specific T cell and B cell responses to vaccine-mediated protection against disease.

Giving RSV some POP(G)

National Jewish Health researchers have shown that a low-cost pulmonary surfactant inhibits binding of respiratory syncytial virus to lung epithelial surfaces. Although issues related to both prophylactic and treatment applications need to be worked out, the researchers believe the path to human trials could be relatively short.