Respiratory syncytial virus infections in congenital heart defects--hospitalizations and costs

Acute Lower Respiratory Infections Associated With Respiratory Syncytial Virus in Children With Underlying Congenital Heart Disease: Systematic Review and Meta-analysis

BACKGROUND

Respiratory syncytial virus (RSV) is the most common viral pathogen associated with acute lower respiratory infections (ALRIs), with significant childhood morbidity and mortality worldwide. Estimates reporting RSV-associated ALRI (RSV-ALRI) severity in children with congenital heart disease (CHD) are lacking, thus warranting the need to summarize the available data. We identified relevant studies to summarize the findings and conducted a meta-analysis of available data on RSV-associated ALRI hospitalizations in children aged <5 years, comparing those with underlying CHD to those without CHD.

METHODS

We conducted a systematic search of existing relevant literature and identified studies reporting hospitalization of children aged <5 years with RSV-ALRI with underlying or no CHD. We summarized the data and conducted (where possible) a random-effects meta-analysis to compare the 2 groups.

RESULTS

We included 18 studies that met our strict eligibility criteria. The risk of severe RSV-ALRI (odds ratio, 2.2; 95% confidence interval [CI], 1.6-2.8), the rate of hospitalization (incidence rate ratio, 2.8; 95% CI, 1.9-4.1), and the case-fatality ratio (risk ratio [RR], 16.5; 95% CI, 13.7-19.8) associated with RSV-ALRI was higher among children with underlying CHD as compared to those without no CHD. The risk of admission to the intensive care unit (RR, 3.9; 95% CI, 3.4-4.5), need for supplemental oxygen therapy (RR, 3.4; 95% CI, .5-21.1), and need for mechanical ventilation (RR, 4.1; 95% CI, 2.1-8.0) was also higher among children with underlying CHD.

CONCLUSION

This is the most detailed review to show more-severe RSV-ALRI among children aged <5 years with underlying CHD, especially hemodynamically significant underlying CHD, as compared those without CHD, supporting a need for improved RSV prophylactics and treatments that also have efficacy in children older than 1 year.

Cost-effectiveness of palivizumab in infants with congenital heart disease: a Swedish perspective

Background

Infants with congenital heart disease (CHD) have an increased risk of morbidity and mortality during a respiratory syncytial virus (RSV) infection. The aim of this study was to estimate the cost-effectiveness of palivizumab as RSV-prophylaxis among infants with CHD, including the effect of delayed heart surgery and asthma.

Methods

A simulation model with data from the literature and health care authorities including costs and utilities was developed to estimate costs and health effects over a lifetime for a cohort of CHD infants receiving palivizumab compared to no RSV-prophylaxis.

Results

The prophylaxis treatment incurred a cost of 3664 EUR per treated infant. However, due to cost-savings from primarily avoiding hospitalizations (5145 EUR/treated infant) and avoiding heart complications due to delayed heart surgery (2082 EUR/treated infant), the RSV-prophylaxis treatment resulted in a total cost-saving of 3833 EUR per treated infant. At the same time, the prophylaxis-treated cohort accumulated more life-years and higher quality of life than the non-prophylaxis cohort.

Conclusion

This study confirms that RSV-prophylaxis in severe CHD infants less than one year of age is cost beneficial. Avoiding delayed heart surgeries is an important benefit of prophylaxis and should be taken into consideration.

Viral Respiratory Infection, a Risk in Pediatric Cardiac Surgery: A Propensity-Matched Analysis

OBJECTIVES

1) To describe the postoperative course and outcomes of cardiac surgery in children with perioperative viral respiratory infection, 2) to evaluate optimal surgical timing for preoperative viral respiratory infection patients, and 3) to define risk stratification.

DESIGN

Retrospective study of children undergoing cardiac surgery. Children were tested using a multiplex polymerase chain reaction (respiratory virus polymerase chain reaction) panel capturing seven respiratory viruses. Respiratory virus polymerase chain reaction testing was routinely performed in patients under 2 years old. Those with negative results yet highly suspected of viral respiratory infection after surgeries would be tested again.

SETTING

A pediatric cardiac surgical ICU of pediatric cardiac surgery department at Fuwai Hospital.

PATIENTS

Children admitted between January 1, 2014, and December 31, 2016, to perform respiratory virus polymerase chain reaction testing and cardiac surgery were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 2,831 patients had respiratory virus polymerase chain reaction testing, and viruses were detected in 91 patients (3.2%), including 35 preoperative and 56 postoperative. Of the 35 preoperative viral respiratory infection patients, there were 29 viral respiratory infection-resolved (patients for whom surgery was postponed until resolution of viral respiratory infection symptoms and negative respiratory virus polymerase chain reaction) and six viral respiratory infection-unresolved (who underwent cardiac surgery before resolution of symptoms and clearance of carriage) patients. Furthermore, there were seven deaths, including one in the preoperative viral respiratory infection-unresolved group and six in the postoperative viral respiratory infection group. A propensity score matching was performed to correct the selection bias and identify the comparable patient groups. Compared to their matched nonviral respiratory infection patients, viral respiratory infection-resolved patients had similar duration of mechanical ventilation and length of stay, while viral respiratory infection-unresolved patients had longer durations of postoperative mechanical ventilation (p = 0.033), PICU (p = 0.028) and hospital length of stay (p = 0.010), and postoperative viral respiratory infection patients had significantly greater duration of postoperative recovery (p < 0.001) and higher mortality (p < 0.001). Earlier diagnosis of postoperative viral respiratory infection was associated with longer mechanical ventilation duration (r = 0.422; p < 0.001). Palliative cardiac surgery was the only variable significantly associated with mortality in multivariate analysis (odds ratio, 12.0; 95% CI, 1.6-87.5; p = 0.014).

CONCLUSIONS

The preoperative-unresolved and postoperative viral respiratory infection were associated with prolonged postoperative recovery, increased severity, and mortality in children with cardiac surgeries. Our results suggested the optimal surgical timing may be after the resolution of viral respiratory infection symptoms and carriage unless the perceived benefits of early surgery outweigh the risk of death, prolonged ventilation, and PICU length of stay. Palliative surgeries were associated with increasing mortality.

Cost of Respiratory Syncytial Virus-Associated Acute Lower Respiratory Infection Management in Young Children at the Regional and Global Level: A Systematic Review and Meta-Analysis

Background

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory infection (ALRI) in young children aged &lt;5 years.

Methods

We aimed to identify the global inpatient and outpatient cost of management of RSV-ALRI in young children to assist health policy makers in making decisions related to resource allocation for interventions to reduce severe morbidity and mortality from RSV in this age group. We searched 3 electronic databases including Global Health, Medline, and EMBASE for studies reporting cost data on RSV management in children under 60 months from 2000 to 2017. Unpublished data on the management cost of RSV episodes were collected through collaboration with an international working group (RSV GEN) and claim databases.

Results

We identified 41 studies reporting data from year 1987 to 2017, mainly from Europe, North America, and Australia, covering the management of a total of 365 828 RSV disease episodes. The average cost per episode was €3452 (95% confidence interval [CI], 3265–3639) and €299 (95% CI, 295–303) for inpatient and outpatient management without follow-up, and it increased to €8591(95% CI, 8489–8692) and €2191 (95% CI, 2190–2192), respectively, with follow-up to 2 years after the initial event.

Conclusions

Known risk factors (early and late preterm birth, congenital heart disease, chronic lung disease, intensive care unit admission, and ventilator use) were associated with €4160 (95% CI, 3237–5082) increased cost of hospitalization. The global cost of inpatient and outpatient RSV ALRI management in young children in 2017 was estimated to be approximately €4.82 billion (95% CI, 3.47–7.93), 65% of these in developing countries and 55% of global costs accounted for by hospitalization. We have demonstrated that RSV imposed a substantial economic burden on health systems, governments, and the society.

Respiratory virus prophylaxis in congenital heart disease

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections and causes up to 200,000 infant deaths a year worldwide. The average rate of hospitalization for severe RSV infection is 5 per 1000 children, and the rate is three-times higher in those with congenital heart disease (CHD). Palivizumab, a monoclonal antibody, reduces hospitalization rates and intensive care admissions. It is used prophylactically and is administered as monthly doses during the RSV season. Hemodynamically unstable CHD is the most susceptible CHD to a severe episode of RSV infection. This review explores current evidence surrounding therapies, patterns of infection and identifies groups which may still be vulnerable to severe RSV infection.

Low age, low birthweight and congenital heart disease are risk factors for intensive care in infants with bronchiolitis

AIM

This study evaluated the incidence and risk factors for intensive care and respiratory support in infant bronchiolitis.

METHODS

This retrospective descriptive case-control study focused on 105 patients treated in the paediatric intensive care unit (PICU) and 210 controls treated in the emergency department or on the paediatric ward in Tampere University Hospital in Finland between 2000 and 2015. Statistically significant risk factors in nonadjusted analyses were included in the adjusted logistic regression.

RESULTS

The average age-specific annual incidence of bronchiolitis requiring PICU admission under the age of 12 months was 1.5/1000/year (range 0.18-2.59). Independently, significant risk factors for PICU admission were as follows: being less than two months old with an adjusted odds ratio (aOR) of 11.5, birthweight of <2000 g (aOR of 15.9), congenital heart disease (CHD) (aOR of 15.9), apnoea (aOR of 7.2) and the absence of wheezing (aOR of 2.2). Significant risk factors for needing respiratory support were a birthweight of <2000 g, an age of less than two months and CHD.

CONCLUSION

Less than 0.1% of infants under the age of 12 months were admitted to the PICU for bronchiolitis. Low age, low birthweight or prematurity and CHD were independently significant risk factors for both intensive care and respiratory support.

Defining the Risk and Associated Morbidity and Mortality of Severe Respiratory Syncytial Virus Infection Among Infants with Congenital Heart Disease

Introduction

The REGAL (RSV Evidence—a Geographical Archive of the Literature) series provide a comprehensive review of the published evidence in the field of respiratory syncytial virus (RSV) in Western countries over the last 20 years. This fourth publication covers the risk and burden of RSV infection in infants with congenital heart disease (CHD).

Methods

A systematic review was undertaken for articles published between January 1, 1995 and December 31, 2015 across PubMed, Embase, The Cochrane Library, and Clinicaltrials.gov. Studies reporting data for hospital visits/admissions for RSV infection among children with CHD as well as studies reporting RSV-associated morbidity, mortality, and healthcare costs were included. The focus was on children not receiving RSV prophylaxis. Study quality and strength of evidence (SOE) were graded using recognized criteria.

Results

A total of 1325 studies were identified of which 38 were included. CHD, in particular hemodynamically significant CHD, is an independent predictor for RSV hospitalization (RSVH) (high SOE). RSVH rates were generally high in young children (<4 years) with CHD (various classifications), varying between 14 and 357/1000 (high SOE). Children (<6 years) with RSV infection spent 4.4–14 days in hospital, with up to 53% requiring intensive care (high SOE). Infants (<2 years) with CHD had a more severe course of RSVH than those without CHD (high SOE). Case fatality rates of up to 3% were associated with RSV infection in children with CHD (high SOE). RSV infection in the perioperative period of corrective surgery and nosocomial RSV infection in intensive care units also represent important causes of morbidity (moderate SOE).

Conclusion

CHD poses a significant risk for RSVH and subsequent morbidity and mortality. RSV infection often complicates corrective heart surgery. To reduce the burden and improve outcomes, further research and specific studies are needed to determine the longer-term effects of severe RSV infection in young children with CHD.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-016-0142-x) contains supplementary material, which is available to authorized users.

Respiratory syncytial virus hospitalisation trends in children with haemodynamically significant heart disease, 1997-2012

OBJECTIVE

The aim of the study was to evaluate the trends in respiratory syncytial virus-related hospitalisations and associated outcomes in children with haemodynamically significant heart disease in the United States of America. Study design The Kids' Inpatient Databases (1997-2012) were used to estimate the incidence of respiratory syncytial virus hospitalisation among children ⩽24 months with or without haemodynamically significant heart disease. Weighted multivariable logistic regression and chi-square tests were used to evaluate the trends over time and factors associated with hospitalisation, comparing eras before and after publication of the 2003 American Academy of Pediatrics palivizumab immunoprophylaxis guidelines. Secondary outcomes included in-hospital mortality, morbidity, length of stay, and cost.

RESULTS

Overall, 549,265 respiratory syncytial virus-related hospitalisations were evaluated, including 2518 (0.5%) in children with haemodynamically significant heart disease. The incidence of respiratory syncytial virus hospitalisation in children with haemodynamically significant heart disease decreased by 36% when comparing pre- and post-palivizumab guideline eras versus an 8% decline in children without haemodynamically significant heart disease (p<0.001). Children with haemodynamically significant heart disease had higher rates of respiratory syncytial virus-associated mortality (4.9 versus 0.1%, p<0.001) and morbidity (31.5 versus 3.5%, p<0.001) and longer hospital length of stay (17.9 versus 3.9 days, p<0.001) compared with children without haemodynamically significant heart disease. The mean cost of respiratory syncytial virus hospitalisation in 2009 was $58,166 (95% CI:$46,017, $70,315).

CONCLUSIONS

These data provide stakeholders with a means to evaluate the cost-utility of various immunoprophylaxis strategies.

Respiratory syncytial virus-associated hospitalizations over three consecutive seasons in children with congenital heart disease

The purpose of this investigation was to analyze the burden of respiratory syncytial virus (RSV)-related hospitalizations in infants and children with congenital heart disease (CHD) over three consecutive RSV seasons. Retrospectively, all children with hemodynamically significant (HS-CHD) and not significant (HNS-CHD) CHD born between 2004 and 2008 at a tertiary care university hospital and identified by ICD-10 diagnoses were included. Data on RSV-related hospitalizations over the first three years of life covering at least three RSV seasons (November-April) were analyzed. The overall incidence of RSV-related hospitalization was 9.6 % (58/602), without a statistically significant difference between HS-CHD and HNS-CHD (7.3 % vs. 10.4 %; p = 0.258). Recommendation of palivizumab prophylaxis did not influence the RSV hospitalization rates between groups. Patients with HS-CHD and early surgery were significantly less often hospitalized due to RSV compared to those with delayed surgery (1.3 % vs. 14.3 %; p = 0.003). The median duration of hospitalization was 8.5 days (HS-CHD: 14 vs.

HNS-CHD

7 days; p = 0.003). Thirteen patients (22.4 %) were admitted to the intensive care unit (ICU), for a median of 10 days. The median age at admission was 2 months, with a significant difference between HS-CHD and HNS-CHD (6 vs. 2 months; p = 0.001). The majority (97 %) of RSV-related hospitalizations occurred before 12 months of age. Patients with HS-CHD had a significantly more severe course of RSV disease and were older at the time of hospitalization. Early surgery seemed to significantly reduce the risk of RSV hospitalization during the first RSV season.

Preventing hospitalizations for respiratory syncytial virus infection

Respiratory syncytial virus infection is the leading cause of lower respiratory tract infections in young children. Palivizumab has minimal impact on RSV hospitilization rates as it is only practical to offer it to the highest risk groups. The present statement reviews the published literature and provides updated recommendations regarding palivizumab use in children in Canada.

Evaluating national guidelines for the prophylactic treatment of respiratory syncytial virus in children with congenital heart disease

AIM

This is the first study to evaluate compliance with the 2003 Swedish national guidelines for prophylactic treatment of respiratory syncytial virus (RSV) in children with congenital heart disease (CHD). We estimated the relative risk (RR) of children with CHD being hospitalised with a RSV infection, studied the extent to which RSV prophylactic treatment with palivizumab corresponded to the guidelines and determined the morbidity of children with CHD who developed RSV infection despite prophylaxis.

METHODS

This national observational study comprised prospectively registered data on 219 children with CHD treated with palivizumab, medical records on RSV cases and information on hospitalisation rates of children with CHD and RSV infection.

RESULTS

The calculated RR of children with CHD being hospitalised with RSV infection was 2.06 (95% CI 1.6-2.6; p < 0.0001) compared with children without CHD. Approximately half of the patients (49%) born before the RSV season and 25% born during the RSV season did not start treatment as recommended by the guidelines.

CONCLUSION

Having CHD increased the rate and estimated RR of children being hospitalised with RSV infection. The guidelines were not followed for about half of the children born before a RSV season and a quarter of the children born during a RSV season and need updating.

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.

Respiratory syncytial virus prophylaxis in children with cardiac disease: a retrospective single-centre study

OBJECTIVES

To examine the characteristics of congenital heart disease patients hospitalised with respiratory syncytial virus infection after prophylaxis and determine the associated comorbidities and the incidence of breakthrough respiratory syncytial virus infections.

STUDY DESIGN

This is a retrospective, single-centre study that was conducted over a period of 7 years. Respiratory syncytial virus infection was identified by classification codes and confirmed by virological tests. Data on baseline demographics, cardiac anomalies, other underlying disease, criteria for hospitalisation, type of respiratory illness and management, complications, and palivizumab prophylaxis were analysed by standard descriptive methods and comparative statistics.

RESULTS

A total of 30 patients were enrolled. The majority were ≤ 2 years (n = 24). The mean admission age was 15.1 months (standard deviation = 18.3). In all, 90% were acyanotic, 40% had haemodynamically significant disease, and 60% had ≥ 1 underlying medical illness. Patients were admitted with: respiratory distress (86.7%), hypoxaemia (66.7%), fever (60%), inability to maintain oral intake (36.7%), and apnoea (16.7%). More than 50% required mechanical ventilation and intensive care with a median stay of 11 days (range: 1-43); the length of hospital stay for all children was 10 days (range: 1-65). Complications included: concurrent bacterial sepsis (20%), electrolyte abnormalities (16.7%), and worsening pulmonary hypertension (13.3%). Of 10 infants ≤ 2 years with haemodynamically significant heart disease, four had received prophylaxis. There was one death, which was attributed to respiratory syncytial virus infection.

CONCLUSIONS

Overall, 185 infants ≤ 2 years with haemodynamically significant cardiac disease received prophylaxis. In all, six qualifying infants missed immunisation and were hospitalised. Breakthrough respiratory syncytial virus infections occurred in 2.2%, demonstrating good efficacy of palivizumab in this population compared with the original, multi-centre, randomised trial.

Respiratory syncytial virus infections in infants and children with congenital heart disease: update on the evidence of prevention with palivizumab

PURPOSE OF REVIEW

Lower respiratory tract infections multiply morbidity and mortality within patients with significant congenital heart disease (CHD). For respiratory syncytial virus (RSV), one of the most important pathogens, immunoprophylaxis with palivizumab has successfully been introduced. The question is which patients will benefit most from this costly preventive treatment.

RECENT FINDINGS

The era after the introduction of palivizumab has revealed a steep decrease in mortality. The markers of success - hospital stays, admission to the intensive care unit, days on mechanical ventilation, and death - consistently favor immunoprophylaxis. The key point of treatment success remains in all cases a careful patient selection, adherence to a time limit of 30 days between the injections and early use after cardiac surgery with cardiopulmonary bypass, as well as avoidance of nosocomial-acquired infections. Preventive therapy with palivizumab in patients with CHD has been investigated in terms of operating efficiency - with the lowest costs per quality-adjusted life years compared with preterm infants with or without bronchopulmonary dysplasia.

SUMMARY

The burden of RSV disease will decline, once a vaccine is available. Meanwhile, immunoprophylaxis with palivizumab is a useful tool for high-risk patients to reduce comorbidity and fatal outcome. Pharmacoeconomic considerations measuring quality-adjusted life years indicate important information about cost-effectiveness.

Monoclonal antibody for reducing the risk of respiratory syncytial virus infection in children

BACKGROUND

Respiratory syncytial virus (RSV) is one of the most important viral pathogens causing acute respiratory infections in children. It results in about 3.4 million hospitalisations annually in children under five. Palivizumab is an anti-RSV monoclonal antibody, administered intramuscularly at a dose of 15 mg/kg once every 30 days. The efficacy and safety of palivizumab has been evaluated in multicentre, randomised controlled trials (RCTs) and a large number of economic evaluations (EEs) have tested its cost-effectiveness.

OBJECTIVES

To assess the effectiveness and safety of palivizumab prophylaxis compared with placebo, or another type of prophylaxis, in reducing the risk of complications (hospitalisation due to RSV infection) in high-risk infants and children. To assess the cost-effectiveness (or cost-utility) of palivizumab prophylaxis compared with no prophylaxis in infants and children in different risk groups.

SEARCH METHODS

We searched CENTRAL 2012, Issue 7, MEDLINE (1996 to July week 4, 2012), EMBASE (1996 to August 2012), CINAHL (1996 to August 2012) and LILACS (1996 to August 2012) for studies of effectiveness and safety. We searched the NHS Economic Evaluations Database (NHS EED 2012, Issue 4), Health Economics Evaluations Database (HEED, 9 August 2012) and Paediatric Economic Database Evaluations (PEDE, 1980 to 2009), MEDLINE (1996 to July week 4, 2012) and EMBASE (1996 to August 2012) for economic evaluations.

SELECTION CRITERIA

We included RCTs comparing palivizumab prophylaxis with a placebo, no prophylaxis or another type of prophylaxis in preventing serious lower respiratory tract disease caused by RSV in paediatric patients at high risk. We included cost-effectiveness analyses and cost-utility analyses comparing palivizumab prophylaxis with no prophylaxis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed risk of bias for the included studies and extracted data for both the RCTs and EEs. We calculated risk ratios (RRs) and their associated 95% confidence intervals (CIs) for dichotomous outcomes and for adverse events (AEs). We provided a narrative summary of results for continuous outcomes, due to missing data on standard deviations. We performed fixed-effect meta-analyses for the estimation of pooled effects whenever there was no indication of heterogeneity between included RCTs. We summarised the results reported in included EEs, such as incremental costs, incremental effectiveness, and incremental cost-effectiveness and/or cost-utility ratios (ICERs), and we calculated ICER present values in 2011 Euros for all studies.

MAIN RESULTS

Of the seven available RCTs, three compared palivizumab with a placebo in a total of 2831 patients, and four compared palivizumab with motavizumab in a total of 8265 patients. All RCTs were sponsored by the drug manufacturing company. The overall quality of RCTs was good, but for most of the outcomes assessed only data from two studies contributed to the analysis. Palivizumab prophylaxis was associated with a statistically significant reduction in RSV hospitalisations (RR 0.49, 95% CI 0.37 to 0.64) when compared to placebo. When compared to motavizumab, palivizumab recipients showed a non-significant increase in the risk of RSV hospitalisations (RR 1.36, 95% CI 0.97 to 1.90). In both cases, the proportion of children with any AE or any AE related to the study drug was similar between the two groups.In terms of economic evidence, we included 34 studies that reported cost-effectiveness and/or cost-utility data for palivizumab prophylaxis compared with no prophylaxis, in high-risk children with different underlying medical conditions. The overall quality of EEs was good, but the variations in modelling approaches were considerable across the studies, leading to big differences in cost-effectiveness results. The cost-effectiveness of palivizumab prophylaxis depends on the consumption of resources taken into account by the study authors; and on the cost-effectiveness threshold set by the healthcare sector in each country.

AUTHORS' CONCLUSIONS

There is evidence that palivizumab prophylaxis is effective in reducing the frequency of hospitalisations due to RSV infection, i.e. in reducing the incidence of serious lower respiratory tract RSV disease in children with chronic lung disease, congenital heart disease or those born preterm.Results from economic evaluations of palivizumab prophylaxis are inconsistent, implying that economic findings must be interpreted with caution. ICER values varied considerably across studies, from highly cost-effective to not cost-effective. The availability of low-cost palivizumab would reduce its inequitable distribution, so that RSV prophylaxis would be available to the poorest countries where children are at greatest risk.

Use of number needed to treat in cost-effectiveness analyses

OBJECTIVE

To review the use of number needed to treat (NNT) and/or number needed to harm (NNH) values to determine their relevance in helping clinicians evaluate cost-effectiveness analyses (CEAs).

DATA SOURCES

PubMed and EconLit were searched from 1966 to September 2012.

STUDY SELECTION AND DATA EXTRACTION

Reviews, editorials, non-English-language articles, and articles that did not report NNT/NNH or cost-effectiveness ratios were excluded. CEA studies reporting cost per life-year gained, per quality-adjusted life-year (QALY), or other cost per effectiveness measure were included. Full texts of all included articles were reviewed for study information, including type of journal, impact factor of the journal, focus of study, data source, publication year, how NNT/NNH values were reported, and outcome measures.

DATA SYNTHESIS

A total of 188 studies were initially identified, with 69 meeting our inclusion criteria. Most were published in clinician-practice-focused journals (78.3%) while 5.8% were in policy-focused journals, and 15.9% in health-economics-focused journals. The majority (72.4%) of the articles were published in high-impact journals (impact factor >3.0). Many articles focused on either disease treatment (40.5%) or disease prevention (40.5%). Forty-eight percent reported NNT as a part of the CEA ratio per event. Most (53.6%) articles used data from literature reviews, while 24.6% used data from randomized clinical trials, and 20.3% used data from observational studies. In addition, 10% of the studies implemented modeling to perform CEA.

CONCLUSIONS

CEA studies sometimes include NNT ratios. Although it has several limitations, clinicians often use NNT for decision-making, so including NNT information alongside CEA findings may help clinicians better understand and apply CEA results. Further research is needed to assess how NNT/NNH might meaningfully be incorporated into CEA publications.

Palivizumab in preventing respiratory syncytial virus-related hospitalization in high-risk infants

Respiratory syncytial virus (RSV) causes seasonal epidemics (winter or wet-season) of serious lower respiratory tract infections in young infants with subsequent increased frequency of recurrent wheezing during early childhood. Palivizumab is a humanized monoclonal antibody that provides immunoprophylaxis against RSV when administered monthly over the RSV season. It significantly reduced hospitalizations in high-risk infants including preterm infants with and without bronchopulmonary dysplasia and infants with hemodynamically significant congenital heart disease. Since its license in 1998, approximately 36 methodologically different economic studies have been performed to prove cost-effectiveness of the product. The majority of cost-effectiveness analyses revealed costs of palivizumab exceeding anticipated savings from reduced RSV hospitalizations. A minority of studies performed cost-effectiveness analyses using incremental cost-effectiveness ratios as costs per quality-adjusted life-year gained. The wide variability in the results of economic studies with estimates ranging from cost savings to incremental costs of a high order of magnitude with its use is discussed, in the light of the continuing burden of RSV disease, the limited treatment modalities, and the continuing research for a vaccine.

Cost-effectiveness of palivizumab in infancy

Respiratory syncytial virus is the most common cause of bronchiolitis, a lower respiratory tract infection occurring in infancy. It is responsible for several rehospitalizations, substantial morbidity and occasional deaths in the UK every year. Palivizumab is a recombinant monoclonal antibody that has been shown to reduce hospitalizations in infected infants. It is licensed for high-risk infants, primarily those born pre-term or with chronic pulmonary or cardiac conditions. Palivizumab is expensive, but several economic analyses have determined highly discrepant costs. This article reviews the limitations of the available efficacy and economic data, and highlights problems in interpretation and extrapolation. We also present the results of a cost-effectiveness analysis relevant to populations of high-risk infants in the UK.

Managing the morbidity associated with respiratory viral infections in children with congenital heart disease

Children with congenital heart disease (CHD) are at risk for increased morbidity from viral lower respiratory tract infections because of anatomical cardiac lesions than can worsen an already compromised respiratory status. Respiratory syncytial virus (RSV) remains an important pathogen in contributing toward the morbidity in this population. Although the acute treatment of RSV largely remains supportive, the development of monoclonal antibodies, such as palivuzumab, has reduced the RSV-related hospitalization rate in children with CHD. This review highlights the specific cardiac complications of RSV infection, the acute treatment of bronchiolitis in patients with CHD, and the search for new therapies against RSV, including an effective vaccine, because of the high cost associated with immunoprophylaxis and its lack of reducing RSV-related mortality.

Impact of palivizumab on RSV hospitalizations for children with hemodynamically significant congenital heart disease

The objective of this study was to evaluate the impact of palivizumab prophylaxis on respiratory syncytial virus (RSV) hospitalizations among children with hemodynamically significant congenital heart disease (CHD). In 2003, the American Academy of Pediatrics (AAP) revised the bronchiolitis policy statement and recommended the use of palivizumab in children <24 months old with hemodynamically significant CHD (HS-CHD). California statewide hospital discharge data from years 2000-2002 (pre-AAP policy revision) were compared to those from years 2004-2006 (post-AAP policy revision). Hospitalizations due to RSV bronchiolitis for children <2 years of age were identified by IDC-9 CM codes 4661.1, 480.1, and 079.6 as the Principal Diagnosis. Children with CHD and children with HS-CHD were identified by the codiagnoses. The overall RSV hospitalization rate was 71 per 10,000 children <2 years of age. Of all RSV hospitalizations, 3.0% were among children with CHD, and 0.50% among children with HS-CHD. HS-CHD patients accounted for 0.56% of RSV hospitalizations in 2000-2002, compared to 0.46% RSV hospitalizations in 2004-2006. That represents a 19% reduction in RSV hospitalizations among HS-CHD patients after 2003. The 19% decrease in RSV hospitalizations equates to seven fewer hospitalizations (76 hospital days) per year among HS-CHD patients. We conclude that, since the recommendation of palivizumab for children with HS-CHD in 2003, the impact on RSV hospitalizations in California among HS-CHD patients has been limited. Considering the high cost of palivizumab administration, the cost-benefit of RSV prophylaxis with palivizumab warrants further investigation.

Cost effectiveness of respiratory syncytial virus prophylaxis: a critical and systematic review

Respiratory syncytial virus (RSV) is the leading cause of infant hospitalization in the US. The economic burden of severe disease is substantial, including hospitalization costs and out-of-pocket expenses. RSV prophylaxis with either RSV immune globulin intravenous (RSV-IGIV) or palivizumab has been shown to be effective in reducing RSV-related hospitalizations. Motavizumab, a new enhanced-potency humanized RSV monoclonal antibody, is presently in clinical trials. RSV-IGIV and palivizumab are associated with high acquisition costs. Cost-effectiveness analyses are therefore of great importance in helping to determine who should receive RSV prophylaxis. Six studies have analysed the cost effectiveness of RSV-IGIV, 14 have analysed the cost effectiveness of palivizumab and five have analysed the cost effectiveness of both agents, two of which directly compared palivizumab with RSV-IGIV. The cost effectiveness of motavizumab has not been studied. Significant variation exists in the modelling used in these analyses. Many studies have examined short-term benefits such as reducing hospitalizations and associated costs, while fewer studies have examined long-term benefits such as QALYs or life-years gained. The payer and society have been the most common perspectives used. The endpoints examined varied and generally did not account for the potential impact of RSV prophylaxis on RSV-related complications such as asthma. While some studies have reported acceptable cost-effectiveness ratios for RSV prophylaxis, the majority failed to show cost savings or cost-effectiveness ratios below commonly accepted thresholds for either RSV-IGIV or palivizumab. Cost effectiveness of RSV prophylaxis tended to be more favourable in populations with specific risk factors, including premature infants < or =32 weeks' gestational age, and infants or children aged < 2 years with chronic lung disease or congenital heart disease. Comparing the results of economic analyses of the two agents suggests palivizumab may be the more cost-effective option in the population for which RSV prophylaxis is recommended. Over time, the acquisition cost of RSV prophylaxis agents, a major cost driver, may decrease, and more acceptable outcomes of economic analyses may result. Albeit important, the results of economic analyses are not the only tool that decision makers rely on, as population-specific risk factors, and efficacy and safety data must be considered when developing treatment guidelines and making clinical decisions.

Preventing RSV bronchiolitis in vulnerable infants: the role of palivizumab

As the vast majority of infants tolerate infection with the respiratory syncytial virus [RSV] well and can be managed in the home, most should not be considered for RSV prophylaxis with palivizumab. However, there exists a subset of vulnerable infants in whom the consequences of RSV infection are greater, with an increased likelihood of intensive care admission and mechanical ventilation. These include children born extremely preterm with chronic neonatal lung disease and infants with haemodynamically significant cardiac disease in whom there exists level II evidence to suggest that palivizumab may reduce their risk of acquiring RSV by approximately 50%. The use of palivizumab varies considerably across the world, based largely on economic considerations. This article reviews the strategies developed to fight RSV infection, the evidence for the use of palivizumab and suggests a reasonable approach clinically and economically to the use of palivizumab, proposing its use selectively in the most vulnerable infants during the first six months of life.

Prospective population-based study of RSV-related intermediate care and intensive care unit admissions in Switzerland over a 4-year period (2001-2005)

OBJECTIVES

Respiratory syncytial virus (RSV) infections are a leading cause of hospital admissions in small children. A substantial proportion of these patients require medical and nursing care, which can only be provided in intermediate (IMC) or intensive care units (ICU). This article reports on all children aged < 3 years who required admission to IMC and/or ICU between October 1, 2001 and September 30, 2005 in Switzerland.

PATIENTS AND METHODS

We prospectively collected data on all children aged < 3 years who were admitted to an IMC or ICU for an RSV-related illness. Using a detailed questionnaire, we collected information on risk factors, therapy requirements, length of stay in the IMC/ICU and hospital, and outcome.

RESULTS

Of the 577 cases reported during the study period, 90 were excluded because the patients did not fulfill the inclusion criteria; data were incomplete in another 25 cases (5%). Therefore, a total of 462 verified cases were eligible for analysis. At the time of hospital admission, only 31 patients (11%) were older than 12 months. Since RSV infection was not the main reason for IMC/ICU admission in 52% of these patients, we chose to exclude this subgroup from further analyses. Among the 431 infants aged < 12 months, the majority (77%) were former near term or full term (NT/FT) infants with a gestational age > or = 35 weeks without additional risk factors who were hospitalized at a median age of 1.5 months. Gestational age (GA) < 32 weeks, moderate to severe bronchopulmonary dysplasia (BPD), and congenital heart disease (CHD) were all associated with a significant risk increase for IMC/ICU admission (relative risk 14, 56, and 10, for GA < or = 32 weeks, BPD, and CHD, respectively). Compared with NT/FT infants, high-risk infants were hospitalized at an older age (except for infants with CHD), required more invasive and longer respiratory support, and had longer stays in the IMC/ICU and hospital.

CONCLUSIONS

In Switzerland, RSV infections lead to the IMC/ICU admission of approximately 1%-2% of each annual birth cohort. Although prematurity, BPD, and CHD are significant risk factors, non-pharmacological preventive strategies should not be restricted to these high-risk patients but also target young NT/FT infants since they constitute 77% of infants requiring IMC/ICU admission.

Overcoming T cell-mediated immunopathology to achieve safe RSV vaccination

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract disease in young children. Premature infants, immunocompromised individuals, and the elderly exhibit an increased risk for the development of severe disease after RSV infection. Currently, there is not a safe and effective RSV vaccine available, in part due to our incomplete understanding of how severe immunopathology was induced following RSV infection of children previously immunized with a formalin-inactivated RSV vaccine. Much of our current understanding of RSV vaccine-enhanced disease can be attributed to the establishment of multiple mouse models of RSV vaccination. Studies analyzing the RSV-specific immune response in mice have clearly demonstrated that both CD4 and CD8 memory T cells contribute to RSV-induced immunopathology. In this review we will focus our discussion on data generated from the mouse models of RSV immunization that have advanced our understanding of how virus-specific T cells mediate immunopathology and RSV vaccine-enhanced disease.

Palivizumab in congenital heart disease: should international guidelines be revised?

Palivizumab has reduced the incidence of respiratory syncytial virus hospitalization in infants and children with congenital heart disease by 45%. Although the mortality rate of children with congenital heart disease hospitalized with respiratory syncytial virus infection has declined from 37% to approximately 3% over the past 3 decades, palivizumab has not been shown to improve mortality. There has been considerable controversy over the cost-effectiveness of administering palivizumab according to international guidelines, including children with congenital heart disease. In particular, the number of children that need to be treated with palivizumab to prevent one respiratory syncytial virus hospitalization increases dramatically in children > 12 months of age. As a result, the authors recommend that countries re-examine their recommendations for providing palivizumab up to age 24 months in children with congenital heart disease.

Palivizumab and the prevention of respiratory syncytial virus illness in pediatric patients with congenital heart disease

Respiratory syncytial virus (RSV) is a significant pathogen for infants and children with congenital heart disease. Non-sustained immunity and failure to develop an effective vaccine has steered RSV management toward a passive immunotherapy strategy in at-risk children. Palivizumab is a humanized murine monoclonal antibody targeting the RSV envelope F glycoprotein. In a Phase III clinical trial palivizumab significantly reduced RSV hospitalization in children with significant congenital heart disease and was proven to be safe. Palivizumab is one of the first monoclonal antibodies to significantly impact a pediatric disease.

Prospects of RNA interference therapy in respiratory viral diseases: update 2006

Respiratory viruses, such as influenza, parainfluenza and respiratory syncytial virus (RSV), claim millions of lives annually. At present, there is no completely effective vaccine or drug against these highly mutable RNA viruses. Passive antibody therapies for RSV, despite their limited application and staggering cost, enjoy a virtual monopoly in a multibillion-dollar global market. Recently, however, pioneering discoveries have launched RNA interference as a novel, nucleic acid-based therapy against viral pathogens. Specifically, small interfering RNAs (siRNAs) offered protection against respiratory syncytial virus, parainfluenza and influenza. siRNA against RSV has entered Phase I clinical trials in humans, and preliminary reports are promising. If appropriately formulated for improved specificity, delivery and pharmacokinetics, siRNAs may indeed become effective antivirals in the clinics of the future. This paper provides an overview of the prospects and hurdles facing the antiviral siRNA drugs, with special emphasis on RSV.