Morbidity and mortality after RSV-associated hospitalizations among premature Canadian infants

Respiratory outcomes, utilization and costs 12 months following a respiratory syncytial virus diagnosis among commercially insured late-preterm infants

OBJECTIVES

To determine, among a commercially-insured population of late-preterm infants, utilization of healthcare resources and costs during the 1 year following a diagnosis of respiratory syncytial virus lower respiratory infection (RSV LRI).

METHODS

Administrative claims for non-capitated, commercially-insured infants <1 year old were used to identify infants diagnosed with RSV LRI and unspecified bronchiolitis/pneumonia (UBP). Infants were stratified by the setting of diagnosis. Infants without evidence of RSV LRI or UBP were selected as a comparison group. Economic and clinical outcomes were analyzed descriptively using propensity score weighting and logged ordinary least squares models were used to examine the relationship between RSV and costs (adjusted to 2006 USD) incurred within 1 year of RSV LRI.

RESULTS

The majority of infants were 3 months or older at the time of RSV LRI or UBP diagnosis. The rate of wheezing was significantly greater for infants in the RSV LRI and UBP cohorts relative to the comparison group (p < 0.001). Infantile asthma rates were 6-9 times higher among RSV LRI and UBP infants than the comparison group. RSV LRI and UBP infants also had significantly more emergency department visits and outpatient visits than the comparison group. The marginal healthcare costs were significantly higher for RSV LRI inpatients ($24,027) and outpatients ($2703) infants than for the comparison group (all p < 0.001).

CONCLUSION

Commercially insured late-preterm infants with RSV infection are at high risk for recurrent wheezing and infantile asthma during the 1-year period after the initial episode and impose a significant economic burden to the healthcare system.

Association of RSV lower respiratory tract infection and subsequent healthcare use and costs: a Medicaid claims analysis in early-preterm, late-preterm, and full-term infants

OBJECTIVE

Healthcare use and costs within 1 year of a respiratory syncytial virus lower respiratory tract infection (RSV-LRI) among Medicaid early-preterm and late-preterm infants compared with full-term infants were evaluated.

METHODS

Infants born during 2003-2005 were identified from the Thomson Reuters MarketScan Multi-State Medicaid Database. Infants <1 year of age were grouped based on RSV-LRI and unspecified bronchiolitis/pneumonia (UBP) diagnosis codes and stratified by inpatient or outpatient setting. Infants without RSV-LRI/UBP were selected for comparison. Economic and clinical outcomes were analyzed descriptively; the relationship between RSV-LRI/UBP and costs incurred within 1 year of infection were analyzed using logged ordinary least squares models. Results were stratified by gestational age.

RESULTS

Most infants were diagnosed with RSV-LRI/UBP after 90 days of chronologic age. Early-preterm infants had the greatest mean number of inpatient, outpatient, and emergency department visits after an RSV-LRI/UBP episode. The marginal costs among infants with RSV-LRI compared with controls were $34,132 (p < 0.001) and $3869 (p = 0.115) among inpatients and outpatients, respectively. Among late-preterm infants, the marginal costs were $17,465 (p < 0.001) and $2158 (p < 0.001) among inpatients and outpatients, respectively. Full-term infants had the lowest marginal costs (inpatients, $9151 [p < 0.001]; outpatients, $1428 [p < 0.001]). Overall, inpatient infants with RSV-LRI/UBP had higher costs than outpatients, suggesting that increased downstream costs are associated with severity of RSV-LRI/UBP disease.

LIMITATIONS

Infants with unknown etiology for bronchiolitis were assigned to the UBP group, which may underestimate the costs of the comparison group.

CONCLUSIONS

The burden of RSV-LRI was substantial among early-preterm Medicaid infants. Costs were also higher among late-preterm relative to full-term infants.

Fatality rates in published reports of RSV hospitalizations among high-risk and otherwise healthy children

OBJECTIVE

To review the fatalities among children hospitalized with respiratory syncytial virus (RSV) infection, and identify factors leading to a fatal outcome.

RESEARCH DESIGN AND METHODS

Review of literature identified from a structured search of PubMed (1966-2009) using the following Medical Subject Headings: respiratory syncytial virus infection; hospitalized; infants; and risk factors. Publications were restricted to: English language; full papers; inclusion of > or =10 subjects; children aged < or =18 years, hospitalization for RSV infection; and deaths reported. Case fatality rates were defined as number of deaths divided by number of children hospitalized for RSV and were calculated for each study.

RESULTS

Thirty-six studies met the inclusion and exclusion criteria. Case fatality rates among children hospitalized for RSV ranged from 0 to 33%. In general, studies showed that subgroups of high-risk children (chronic lung disease [CLD] 3.5-23%, congenital heart disease [CHD] 2-37%, and prematurity 0-6.1%) had higher fatality rates than older or otherwise healthy children (consistently <1%). Presence of severe underlying comorbidities such as neuromuscular disease, immunosuppression, and malignancies was associated with death among term and/or older (>1 year) children. Higher fatality rates were reported for infants receiving intensive unit care (1.1-8.6%), extracorporeal life support (33%) or for those who acquired nosocomial RSV infection (0-12.2%). The majority of studies did not report cause of death and clinical details of the fatal cases were often not provided. Other limitations of this review include our search limits, the possibility of inherent bias in our methodology that could result in an under or over estimation of case-fatality rates, and potential publication bias.

CONCLUSIONS

Children at high risk for RSV (CLD, CHD and prematurity), those with severe underlying comorbidities, or those with nosocomial RSV appear to be at increased risk for death after RSV hospitalization. More data are needed on cause of death and how much is directly attributable to RSV.

Healthcare costs within a year of respiratory syncytial virus among Medicaid infants

Limited research exists on the economic impact of respiratory syncytial virus lower respiratory infection (RSV LRI) among vulnerable infant populations. This study evaluated healthcare costs of full-term and late-preterm Medicaid infants with RSV LRI within 1 year of infection. Medicaid administrative claims were used to conduct a retrospective study of infants born 2003-2005. Full-term and late-preterm infants <1 year old were assigned to groups based on RSV LRI and unspecified bronchiolitis/pneumonia (UBP) diagnosis codes and stratified by setting of diagnosis. Infants without evidence of RSV LRI/UBP were selected as a comparison group. Economic and clinical outcomes were analyzed descriptively using propensity score weighting, and logged ordinary least squares models were used to examine relationship between RSV and costs incurred within 1 year of infection. RSV LRI and UBP infants, regardless of gestational age or healthcare setting, were more likely to experience respiratory diagnoses of wheezing and infantile asthma versus comparisons. Adjusted and weighted healthcare costs were significantly higher for all groups of RSV LRI and UBP infants relative to comparison infants (P < 0.001). Among late-preterm infants with inpatient and outpatient RSV, marginal costs compared with controls were $17,465 and $2,158, respectively. Costs for RSV LRI and UBP Medicaid infants are substantial. While much of the costs result from initial RSV episodes, higher post-episode costs and rates of respiratory events, procedures, and medications in RSV and UBP infants versus comparisons indicate long-term economic impact from infection and the impact is greater among late-preterm compared to full-term infants.

Respiratory morbidity and lung function in preterm infants of 32 to 36 weeks' gestational age

Normal lung development follows a series of orchestrated events. Premature birth interrupts normal in utero lung development, which results in significant alterations in lung function and physiology. Increasingly, there are reports documenting the broad range of complications experienced by infants aged 34 to 36 weeks' gestational age (GA). Our objective was to summarize the evidence demonstrating respiratory system vulnerability in infants aged 34 to 36 weeks' GA and to review the developmental and physiologic principles that underlie this vulnerability. A comprehensive search for studies that reported epidemiologic data and respiratory morbidity was conducted on the PubMed, Medline, Ovid Biosis, and Embase databases from 2000 to 2009 by using medical subject headings "morbidity in late preterm infants," "preterm infants and lung development," "prematurity and morbidity," and "prematurity and lung development." Because the number of studies exclusive to infants aged 34 to 36 weeks' GA was limited, selected studies also included infants aged 32 to 36 weeks' GA. Of the 24 studies identified, 16 were retrospective population-based cohort studies; 8 studies were observational. These studies consistently revealed that infants born at 32 to 36 weeks' GA, including infants of 34 to 36 weeks' GA, experience substantial respiratory morbidity compared with term infants. Levels of morbidity were, at times, comparable to those observed in very preterm infants. The developmental and physiologic mechanisms that underlie the increased morbidity rate and alterations in respiratory function are discussed. We also present evidence to demonstrate that the immaturity of the respiratory system of infants 34 to 36 weeks' GA at birth results in increased morbidity in infancy and leads to deficits in lung function that may persist into adulthood.

[Clinical consensus on respiratory syncytial virus (RSV) infection prophylaxis and the use of palivizumab in paediatric cardiology.]

BACKGROUND

Following the results of the CIVIC study, the SECPCC proposes to revise its recommendations for the prevention of RSV, taking into account the new evidence, as well as the preventive experience of paediatric cardiologists. For this purpose a structured method of professional consensus has been chosen.

OBJECTIVES

To develop a Spanish clinical consensus on preventing infection by RSV under the auspices of the Sociedad Española de Cardiología Pediátrica y Cardiopatías Congénitas.

METHODS

Delphi Consensus modified in two rounds. The study was conducted in four phases: 1) constitution of a Scientific Committee for bibliographic review and submission of the recommendations for discussion, 2) constitution of an Expert Panel with 75 representatives in the speciality, 3) postal survey organised in two rounds and intermediate processing of opinions, and issuing of a report to the panellists, and 4) discussion of the results in a face-to-face meeting of the Scientific Committee.

RESULTS

Consensus was reached on 54 of the 70 preventive recommendations analysed. With respect to the 16 remaining issues, no consensus was reached, due to differences in professional opinion and the absence of established criteria among the majority of the experts.

CONCLUSIONS

A set of recommendations for RSV prophylaxis in cardiology was developed and updated, rated in accordance with the degree of professional consensus on which they were based. These can be considered valid until such time as new scientific information emerges that warrants a further review.

[Consensus conference on acute bronchiolitis (VI): prognosis of acute bronchiolitis. Review of scientific evidence]

We present a review of the evidence on prognosis of acute bronchiolitis, risk factors for severe forms, symptom or severity scores and risk of post-bronchiolitis asthma. Documented risk factors of long stay or PICU admission in hospitalized patients are: bronchopulmonary dysplasia and/or chronic lung disease, prematurity, congenital heart disease and age less than 3 months. Other less well documented risk factors are: tobacco exposure, history of neonatal mechanical ventilation, breastfeeding for less than 4 months, viral co-infection and other chronic diseases. There are several markers of severity: toxic appearance, tachypnea, hypoxia, atelectasis or infiltrate on chest radiograph, increased breathing effort, signs of dehydration, tachycardia and fever. Although we have some predictive models of severity, none has shown sufficient predictive validity to recommend its use in clinical practice. While there are different symptom or severity scores, none has proven to be valid or accurate enough to recommend their preferable application in clinical practice. There seems to be a consistent and strong association between admission due to bronchiolitis and recurrent episodes of wheezing in the first five years of life. However it is unclear whether this association continues in subsequent years, as there are discordant data on the association between bronchiolitis and asthma.

Outcomes of palivizumab prophylaxis for respiratory syncytial virus infection in preterm children with bronchopulmonary dysplasia at a single hospital in Korea from 2005 to 2009

This study was performed to evaluate the utilization and outcomes of palivizumab in high risk children born prematurely with chronic lung disease (CLD). A retrospective review of 128 patients was conducted from September 2004 to March 2009 at the Ajou University Hospital. All patients were diagnosed with CLD, were born at Collapse

Key Words

• Chronic Lung Disease
• Hospitalization
• Palivizumab Prophylaxis, Respiratory Syncytial Viruses
• Preterm Children

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MESH Headings

• Antibodies, Monoclonal/therapeutic use
• Antibodies, Monoclonal, Humanized
• Antiviral Agents/therapeutic use
• Bronchopulmonary Dysplasia/complications
• Bronchopulmonary Dysplasia/diagnosis
• Demography
• Hospitalization
• Humans
• Infant
• Infant, Newborn
• Palivizumab
• Premature Birth
• Republic of Korea
• Respiratory Syncytial Virus Infections/complications
• Respiratory Syncytial Virus Infections/prevention & control
• Retrospective Studies
• Risk Factors
• Treatment Outcome

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Grants Collapse

Affiliation(s)

Seung Gu Chang Department of Pediatric, Ajou University School of Medicine, Suwon, Korea
Moon Sung Park Department of Pediatric, Ajou University School of Medicine, Suwon, Korea
Jae Eun Yu Department of Pediatric, Ajou University School of Medicine, Suwon, Korea

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Cost effectiveness of palivizumab in Spain: an analysis using observational data

OBJECTIVES

To assess the cost effectiveness of palivizumab for prevention of severe respiratory syncytial virus (RSV) disease in high-risk infants in Spain, incorporating country-specific observational hospitalisation data.

METHODS

An existing decision tree model, designed using data from a large international clinical trial of palivizumab versus no prophylaxis, was updated to include Spanish observational hospitalisation data. The analysis was performed for preterm children born at or before 32 weeks gestational age, who are at high risk of developing severe RSV disease requiring hospitalisation. Data sources included published literature, official price/tariff lists and national population statistics. The primary perspective of the study was that of the Spanish National Health Service in 2006.

RESULTS

The base-case analysis included the direct medical costs associated with palivizumab prophylaxis and hospital care for RSV infections. Use of palivizumab produces an undiscounted incremental cost-effectiveness ratio (ICER) of euro6,142 per quality-adjusted life-year (QALY), and a discounted ICER of euro12,814/QALY.

CONCLUSION

Palivizumab provides a cost-effective method of prophylaxis against severe RSV disease requiring hospitalisation among preterm infants in Spain.

The cost effectiveness of palivizumab: a systematic review of the evidence

OBJECTIVE

Palivizumab is a prophylactic therapy shown to reduce the number of respiratory syncytial virus (RSV)-related hospitalizations but has a high acquisition cost. The objective was to systematically examine the cost effectiveness of palivizumab in defined infant groups and identify important cost and outcome determinants.

METHODS

Literature searches of MedLine, the Cost-Effectiveness Analysis registry and the UK NHS Economic Evaluation Database (NHS EED) were conducted to identify economic evaluations of palivizumab compared to no prophylactic treatment for RSV prevention in any infant population. Study quality was evaluated using Quality of Health Economic Studies (QHES) criteria and results converted to 2009 CAN$ for comparison.

RESULTS

A total of 23 articles meeting inclusion criteria were identified, including 11 cost-utility analyses (CUAs) and 12 cost-effectiveness analyses (CEAs). Quality of individual analyses was fairly high (range 60-100, median 86). Results ranged from cost dominance for prophylaxis to $3,365,769/QALY depending on population, outcome measures, and input parameters. Base-case and sensitivity-analysis mortality rates varied between studies and influenced results.

CONCLUSIONS

RSV prophylaxis with palivizumab is cost effective in specific groups of high-risk infants, especially those with multiple environmental risk factors. Cost-effectiveness estimates vary between populations and settings and are more positive in those at highest risk for RSV hospitalization.

LIMITATIONS

Direct comparison of the published reports was limited by restriction to English language articles and the varied methodologies, input measures, and populations across the studies reviewed. Although reported currencies were converted to a common unit for comparison, this does not completely account for monetary and inflation differences.

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.

Changing costs and the impact on RSV prophylaxis

OBJECTIVE

Acquisition costs of palivizumab have increased in Canada since 2007. This analysis aims to re-evaluate the cost effectiveness of palivizumab in Canada for premature infants born between 32 and 35 weeks' gestational age using updated 2010 healthcare costs compared to those used in a 2007 decision analytic model.

METHODS

New costs (CAN$) were acquired from the same Health Canada and Ontario Ministry of Health sources that were utilized in the previously published 2007 model. Palivizumab prices were acquired from Abbott Laboratories Ltd., current as of August 2010.

RESULTS

Incremental cost-effectiveness ratios (ICERs) rose by $742, going from $30,618/QALY to $31,360/QALY. ICER changes increased from a range of $801,297 to $820,701 for infants with zero risk factors to a decrease from $808 to $192 for infants with four or more risk factors.

CONCLUSIONS

Palivizumab ICERs remained fairly stable from 2007 to 2010. The original recommendation stating that palivizumab is cost effective in infants born between 32 and 35 weeks' GA with two or more risk factors, or who are at moderate-to-high risk based on a risk assessment model, does not change. Analyses founded on evolving country-specific variables are needed in order to accurately reassess the cost effectiveness of interventions as costs change worldwide.

LIMITATIONS

There are a limited number of publications reporting mortality in premature Canadian infants with RSV as a primary outcome. In addition, conclusions drawn from this analysis are country-specific and limited to premature infants dwelling in Canada.

Compliance with RSV prophylaxis: Global physicians' perspectives

Respiratory syncytial virus (RSV) is a significant cause of morbidity in high-risk infants. Palivizumab is proven to prevent serious RSV disease, but compliance with prophylaxis (monthly doses during the RSV season) is essential to ensure protection. We invited 453 pediatricians to participate in a survey to identify their perspectives of barriers to compliance and interventions to improve compliance with palivizumab prophylaxis schedules. One hundred physicians from five continents completed the survey, identifying caregiver inconvenience, distance to clinic, cost of prophylaxis, and lack of understanding of the severity of RSV as the most common reasons for noncompliance. They recommended provision of educational materials about RSV, reminders from hospital or clinic, and administration of prophylaxis at home to increase compliance. Globally, physicians recognize several obstacles to prophylaxis compliance. This survey suggests that focused proactive interventions such as empowering caregivers with educational materials and reducing caregiver inconvenience may be instrumental to increase compliance.

Total healthcare costs in the US for preterm infants with respiratory syncytial virus lower respiratory infection in the first year of life requiring medical attention

BACKGROUND

Respiratory syncytial virus (RSV) lower respiratory infection (LRI) is the most common cause of hospitalization among infants <1 year of age. The healthcare costs of preterm infants with RSV LRI were compared with those without RSV LRI in the first year of life.

METHODS

This retrospective cohort study propensity-matched premature infants < or =36 weeks' gestational age (wGA) and/or < or =2499 g birth weight, born May 1, 2001 through April 30, 2006 (five RSV seasons) with RSV LRI to those without RSV LRI in a national United States health plan. The primary outcome was first-year healthcare costs and utilization excluding the birth hospitalization compared between the study cohorts. Subgroup analysis evaluated costs and healthcare resource utilization by GA (< or =32 wGA and 33-36 wGA) and hospitalization status (hospitalized and outpatient).

RESULTS

A total of 2995 infants with RSV LRI were matched to 2995 controls. Infants with RSV LRI had $9115 higher healthcare costs (RSV LRI group: $19 559; control group: $10 444; p < 0.001) in the first year of life. Late preterm infants (33-36 wGA) with an RSV hospitalization incurred $21 977 higher costs (p < 0.001) and those with an outpatient RSV LRI incurred $3898 higher costs (p < 0.001) compared to corresponding controls. Similar results were found among infants < or =32 wGA with higher costs in the RSV LRI group. Rates of all-cause hospitalizations, emergency department visits, and ambulatory visits were significantly higher among infants with RSV LRI compared to controls.

CONCLUSION

Development of RSV LRI among preterm and late preterm infants is associated with significantly higher healthcare costs in the first year of life. These findings must be considered in the context of potential study limitations that may have over- or underestimated costs, such as unconfirmed RSV infection, unintentional omission of fatal cases, and unobserved imbalances between groups.

Risk factors for lower respiratory tract infection death among infants in the United States, 1999-2004

OBJECTIVE

To describe maternal and birth-related risk factors associated with lower respiratory tract infection (LRTI) deaths among infants.

METHODS

Records for infants with LRTI as a cause of death were examined by using the linked birth/infant death database for 1999-2004. Singleton infants dying with LRTI and a random sample of surviving singleton infants were compared for selected characteristics.

RESULTS

A total of 5420 LRTI-associated infant deaths were documented in the United States during 1999-2004, for an LRTI-associated infant mortality rate of 22.3 per 100,000 live births. Rates varied according to race; the rate for American Indian/Alaska Native (AI/AN) infants was highest (53.2), followed by black (44.1), white (18.7), and Asian/Pacific Islander infants (12.3). Singleton infants with low birth weight (<2500 g) were at increased risk of dying with LRTI after controlling for other characteristics, especially black infants. Both AI/AN and black infants born with a birth weight of > or =2500 g were more likely to have died with LRTI than other infants of the same birth weight. Other risk factors associated with LRTI infant death included male gender, the third or more live birth, an Apgar score of <8, unmarried mother, mother with <12 years of education, mother <25 years of age, and mother using tobacco during pregnancy.

CONCLUSIONS

Low birth weight was associated with markedly increased risk for LRTI-associated death among all of the racial groups. Among infants with a birth weight of > or =2500 g, AI/AN and black infants were at higher risk of LRTI-associated death, even after controlling for maternal and birth-related factors. Additional studies and strategies should focus on the prevention of maternal and birth-related risk factors for postneonatal LRTI and on identifying additional risk factors that contribute to elevated mortality among AI/AN and black infants.

Predictive value of the respiratory syncytial virus risk-scoring tool in the term infant in Canada

BACKGROUND

Palivizumab prophylaxis against respiratory syncytial virus (RSV) infection has been widely adopted for high-risk infants during the RSV season, based on country-specific guidelines.

OBJECTIVE

To determine if a validated, risk-scoring tool (RST), can be applied to term, RSV-positive infants seen in the emergency room (ER) to predict need for hospitalization, in order to target prophylaxis cost effectively at a selected group of children.

DESIGN

Retrospective, descriptive study.

SETTING

McMaster Children's Hospital in Hamilton, Ontario, Canada.

PARTICIPANTS

A total of 72, consecutive, term, RSV-positive cases were identified retrospectively, from November through April during the 2006-2007 RSV season.

METHODS

A questionnaire/chart review was conducted on 68 of 72 cases, to determine risk categories based on the RST. Four, trained abstractors, extracted pertinent data from the medical records of RSV-positive patients. Means, standard deviations (SD), and percents were used to describe the study variables for hospitalized and ER patients discharged home. Chi-square tests were used to compare infants' risk factors to hospitalization. ANOVA was used for comparisons within and between risk groups and RST scores. A p-value of <0.05 was considered statistically significant.

RESULTS

The majority of infants scored in the low-risk category (n = 44), versus moderate (n = 16) or high risk (n = 8). Within the low-risk category, 27 (61%) of children were admitted to hospital compared to 17 (39%) who were treated in the ER and discharged home. The mean RST scores for those admitted to the pediatric intensive care unit/ward, the ward only, or those discharged home from the ER were 48.3 (n = 10), 41.0 (n = 36), and 36.5 (n = 22), respectively (p = 0.17). The mean number of risk factors for those discharged home versus hospitalized patients was 2.5 (1.3) and 2.97 (1.13), respectively (p = 0.15). Only two of eight cases in the high-risk group required intensive care.

CONCLUSIONS

Overall, the risk-scoring tool did not discriminate between low versus moderate- to high-risk RSV-positive term infants who require hospitalization which has cost implications, since universal prophylaxis of this cohort would be financially prohibitive. A larger study is necessary to establish risk factors that more accurately determine RSV hospitalization among term infants.

Severe respiratory syncytial virus (RSV) infection in infants with neuromuscular diseases and immune deficiency syndromes

Respiratory syncytial virus (RSV) is an important cause of lower respiratory tract infection (LRTI) in infants and children. There is growing evidence of severe RSV disease in infants with neuromuscular diseases and immune deficiency syndromes. Factors predisposing to a more severe course of RSV disease in neuromuscular diseases include the impaired ability to clear secretions from the airways due to ineffective cough, respiratory muscle weakness, high prevalence of gastro-oesophageal reflux and swallowing dysfunction which leads to aspiration. Similarly, pulmonary disease is a common presenting feature and complication of T-cell immunodeficiency. Infants with severe congenital and acquired immune deficiency syndromes may demonstrate prolonged viral shedding in RSV LRTI and are reported to have increased morbidity and mortality associated with RSV infection. Although not indicated in most guideline statements, palivizumab prophylaxis for these uncommon underlying conditions is under consideration by clinicians. Prospective studies are needed to determine the burden of RSV disease in these children.

Risk-Scoring Tool for respiratory syncytial virus prophylaxis in premature infants born at 33-35 completed weeks' gestational age in Canada

OBJECTIVE

To study the impact of the Risk-Scoring Tool (RST) as a strategy for targeting prophylaxis effectively in 33-35-week gestational age (GA) Canadian infants who range from low to high risk by evaluating the subsequent incidence of respiratory syncytial virus (RSV) infections resulting in emergency room (ER) visits and hospitalization.

DESIGN

Prospective, descriptive study.

SETTING

McMaster Children's Hospital and St Joseph's Healthcare in Hamilton, Ontario.

PARTICIPANTS

Premature infants between 33 and 35 weeks' completed gestation who were less than 6 months' chronological age at the start of, or during, the local 2005-2008 RSV winter seasons.

METHODS

A validated, Canadian RST was used to calculate a total risk score based on seven risk factors. Only infants at moderate (RST score 49-64) and high risk (RST score 65-100) received palivizumab at monthly intervals from November to April and were followed during the respective RSV seasons. All parents received information on RSV prevention at hospital discharge. Parents of all recruited infants were contacted by telephone in May at the end of each season, and medical records were checked to determine ER visits for RSV-related respiratory tract infections and RSV hospitalization. Means, standard deviations, ranges, and percents were used to describe the variables for patients enrolled in the study.

RESULTS

Over 3 years, 430 infants were recruited. Of these, 346 (81%), 57 (13%), and 27 (6%) were in the low-, moderate- and high-risk categories, respectively, based on their risk scores. A total of 78 (18.1%) infants received full courses of palivizumab. Six out of 57 (10.5%) infants in the moderate-risk group did not receive prophylaxis, while all 27 high-risk group infants received palivizumab. Seven (1.6%) infants were RSV-positive and five (low-risk) infants were hospitalized. One high-risk, RSV-positive infant, was seen in the ER, and discharged home. There were no statistical differences in the number of infants with RSV-related ER visits and hospitalizations within the risk category groups (p = 0.43). The limitations of this study include the observational design and the relatively small sample size.

CONCLUSIONS

The RST is a practical, easy-to-use instrument to guide judicious RSV prophylaxis for moderate-high-risk, 33-35-week GA infants. It is cost-effective, reducing hospitalization in infants who are most 'at-risk', while avoiding prophylaxis in a large segment (81.9%) of this GA cohort who are considered low risk for RSV infection.

Cost-utility analysis of palivizumab in Italy: results from a simulation model in the prophylaxis of respiratory syncytial virus infection (RSV) among high-risk preterm infants

INTRODUCTION

The aim of this study was to assess the cost-utility of palivizumab versus no prophylaxis in the prevention of respiratory syncytial virus infection among high-risk preterm infants.

METHODS

We used and adapted a pre-existent model in which two cohorts of patients received palivizumab or no prophylaxis. The patients were followed for their expected lifetimes. The economic evaluation was conducted from the perspective of the Italian National Health Service. We considered Life-Years Gained (LYGs), Quality-Adjusted Life-Years (QALYs) and direct medical costs (pharmacological treatment, hospitalization, recurrences for wheezing, etc.). LYGs and QALYs were based on the results of a double blind cohort study with prospective follow-up and direct medical costs were based on Italian treatment patterns. Benefits and costs were discounted at 3%. Costs were assessed in 2007 Euros. Sensitivity and threshold analysis on key clinical and economic parameters were performed.

RESULT

For the two cohorts, the expected life-years (per patient) with palivizumab versus no prophylaxis were 29.842 and 29.754 years, respectively. Quality-adjusted life years (per patient) with palivizumab were 29.202, and for no prophylaxis were 29.043. The expected cost (per patient) was euro 6,244.20 with palivizumab and euro 4,867.70 with no prophylaxis. We calculated for palivizumab versus no prophylaxis the incremental cost per LYG and per QALY gained. It was euro 15,568.65 and euro 8,676.74, respectively.

CONCLUSION

This study suggests that, compared with no prophylaxis, palivizumab is cost-effective in the prevention of respiratory syncytial virus infection among high risk preterm infants.

Impact of respiratory syncytial virus in the United States

PURPOSE

Respiratory syncytial virus (RSV) infection is most common in infants and young children, with almost all children experiencing at least one infection by their second birthday.

SUMMARY

RSV is the leading cause of upper and lower respiratory tract infections in infants and young children, and is the most common cause of bronchiolitis and pneumonia in children younger than one year of age. Since infection with RSV does not result in permanent immunity, repeat infections are common, often occurring during the same RSV season. RSV bronchiolitis is the leading cause of hospitalization in children younger than age one, and this virus is associated with approximately 75,000 to 125,000 hospitalizations annually in the United States. Children hospitalized for RSV bronchiolitis during the first year of life are at an increased risk of respiratory problems, such as wheezing and allergic asthma, throughout childhood and into adolescence. RSV-related mortality has decreased over the last 20 years; however, RSV is still the leading cause of viral deaths in infants.

CONCLUSION

RSV infection is associated with significant disease burden in infants and young children in terms of hospitalization, related complications, and even mortality. The economic burden resulting from RSV disease is also substantial, with significantly higher costs seen in children with risk factors for severe disease and RSV-related complications.

The cost effectiveness of palivizumab in term Inuit infants in the Eastern Canadian Arctic

INTRODUCTION

Canadian, Inuit, full term infants have the highest rate of respiratory syncytial virus (RSV) infection globally, which results in substantial costs associated hospitalisation.

METHODS

Decision-analytical techniques were used to estimate the incremental cost-effectiveness ratio (ICER) for palivizumab compared to no prophylaxis for Inuit infants of all gestational age. The time horizon was that of life-time follow-up, and costs and effectiveness were discounted at 5% per year. Costs (2007 CAD$) for palivizumab, hospitalisation (including medical evacuation, intensive care unit [ICU]), physician visits, and transportation were calculated based on the Canadian payer's perspective. Benefits on decreasing RSV hospitalisation were expressed as quality-adjusted life-years (QALYs). One-way and probabilistic sensitivity analysis (PSA) were conducted, varying: mortality rates, utilities, length of stay in hospital and ICU.

RESULTS

For all of Baffin Island infants (<1 year), the ICER was $39,435/QALY. However, when infants were grouped by age and area of residence, those residing in Iqaluit (<1 year) had an ICER of $152,145/QALY, while those residing in rural areas (outside of Iqaluit) had an ICER of $24,750/QALY. Prophylaxis was a dominant strategy (cost saving) for rural infants under 6 months of age, with the PSA demonstrating that it was dominant 98% of the time.

CONCLUSIONS

The ICERs suggested that palivizumab is a cost-effective option for the prevention of RSV for Inuit infants on Baffin Island compared to no prophylaxis. Palivizumab is highly cost effective in Arctic infants <1 year of age specifically residing outside of Iqaluit and is a dominant strategy for those under 6 months of age in rural areas. However, palivizumab is not cost effective compared to no treatment for infants of all ages residing in Iqaluit.

Cost effectiveness of palivizumab for RSV prevention in high-risk children in the Netherlands

BACKGROUND

Respiratory syncytial virus (RSV) is a common pathogen that is the leading cause of lower respiratory tract infections in young children. High-risk children are at risk of severe infection, which may require hospitalisation. RSV is also associated with a high risk for respiratory morbidity and mortality, which may have long-term clinical and economic consequences.

OBJECTIVE

To assess the cost effectiveness of palivizumab, a humanised monoclonal antibody, used as prevention against severe respiratory syncytial virus (RSV) infection requiring hospitalisation, in the indication of preterm infants and infants with preterm/bronchopulmonary dysplasia and in the second indication of children with congenital heart disease in the Dutch healthcare setting.

METHODS

A decision-tree model was used to estimate the cost effectiveness of palivizumab, used as a preventative treatment against severe respiratory syncytial virus (RSV) infection, in high-risk groups of children in the Netherlands. The analysis was based on a lifetime follow-up period in order to capture the impact of palivizumab on long-term morbidity and mortality resulting from an RSV infection. Data sources included published literature, the palivizumab pivotal trials, official price/tariff lists and national population statistics. The study was conducted from the perspective of society in the Netherlands.

RESULTS

The use of palivizumab results in undiscounted incremental cost-effectiveness ratios of €12,728/QALY and €4,256/QALY in preterm/bronchopulmonary dysplasia and congenital heart disease indications, respectively. Inclusion of indirect costs leads to even more favourable cost-effectiveness outcomes. The study is limited by a number of conservative assumptions. It was assumed that palivizumab only affects the occurrence of RSV hospitalisation and does not influence the severity of the RSV infection. Another assumption was that international clinical trial data and data on utilities could be applied to the Dutch healthcare setting.

CONCLUSION

Palivizumab provides cost-effective prophylaxis against RSV in high-risk infants. The use of palivizumab in these children results in positive short- and long-term health-economic benefits.

A predictive model for respiratory syncytial virus (RSV) hospitalisation of premature infants born at 33-35 weeks of gestational age, based on data from the Spanish FLIP Study

BACKGROUND

The aim of this study, conducted in Europe, was to develop a validated risk factor based model to predict RSV-related hospitalisation in premature infants born 33-35 weeks' gestational age (GA).

METHODS

The predictive model was developed using risk factors captured in the Spanish FLIP dataset, a case-control study of 183 premature infants born between 33-35 weeks' GA who were hospitalised with RSV, and 371 age-matched controls. The model was validated internally by 100-fold bootstrapping. Discriminant function analysis was used to analyse combinations of risk factors to predict RSV hospitalisation. Successive models were chosen that had the highest probability for discriminating between hospitalised and non-hospitalised infants. Receiver operating characteristic (ROC) curves were plotted.

RESULTS

An initial 15 variable model was produced with a discriminant function of 72% and an area under the ROC curve of 0.795. A step-wise reduction exercise, alongside recalculations of some variables, produced a final model consisting of 7 variables: birth +/- 10 weeks of start of season, birth weight, breast feeding for < or = 2 months, siblings > or = 2 years, family members with atopy, family members with wheeze, and gender. The discrimination of this model was 71% and the area under the ROC curve was 0.791. At the 0.75 sensitivity intercept, the false positive fraction was 0.33. The 100-fold bootstrapping resulted in a mean discriminant function of 72% (standard deviation: 2.18) and a median area under the ROC curve of 0.785 (range: 0.768-0.790), indicating a good internal validation. The calculated NNT for intervention to treat all at risk patients with a 75% level of protection was 11.7 (95% confidence interval: 9.5-13.6).

CONCLUSION

A robust model based on seven risk factors was developed, which is able to predict which premature infants born between 33-35 weeks' GA are at highest risk of hospitalisation from RSV. The model could be used to optimise prophylaxis with palivizumab across Europe.

Cost-effectiveness of palivizumab against respiratory syncytial viral infection in high-risk children in Austria

OBJECTIVE

The aim of this study was to estimate the cost-effectiveness of palivizumab, a monoclonal antibody against severe respiratory syncytial virus infection, in high-risk infants in Austria.

METHODS

A decision tree model was developed to determine cost-effectiveness in infants born prematurely (<or=35 weeks' gestational age), those with bronchopulmonary dysplasia (BPD), and children with congenital heart disease (CHD). The primary perspective of the analysis was that of the compulsory health insurance fund. The societal perspective was also considered.

RESULTS

From the health insurance fund perspective, including the costs associated with asthma, the incremental cost-effectiveness ratio (cost per quality-adjusted life year [QALY] gained) without discounting was estimated to be euro 4484 (2006 euros) in preterm infants, euro 6719 in children with BPD, and euro 2668 in the CHD population. When discounted, these figures increased to euro 14,439, euro 21,672, and euro 9754, respectively. The results from the societal perspective were substantially more cost-effective in all populations. The undiscounted cost per QALY was euro 1435 in preterm infants, euro 4881 in children with BPD, and euro 251 in the CHD group. Discounted figures were euro 4623, euro 15,741, and euro 917, respectively. Sensitivity analyses confirmed the robustness of the model, and scenario analyses found that the inclusion of indirect costs led to further improvement in the cost-effectiveness outcomes for palivizumab.

CONCLUSION

Use of palivizumab was cost-effective compared with no prophylaxis in high-risk infants and children in Austria.

The cost-effectiveness of palivizumab for respiratory syncytial virus prophylaxis in premature infants with a gestational age of 32-35 weeks: a Canadian-based analysis

BACKGROUND

Prophylactic therapy with palivizumab, a humanized monoclonal antibody, has been shown to reduce the number of respiratory syncytial virus (RSV)-related hospitalizations in preterm infants, including those in the 32-35 weeks' gestational age (GA) subgroup. The cost-effectiveness of this therapy in Canada is unknown.

OBJECTIVES

To evaluate the cost-effectiveness of palivizumab as respiratory syncytial virus prophylaxis in premature infants born at 32-35 weeks' GA.

DESIGN

A decision analytic model was designed to compare both direct and indirect medical costs and benefits of prophylaxis in this subgroup of premature infants. Sensitivity analyses were performed to ascertain the robustness of the model for five point estimates: mortality rate, discounting rates, health-utility values, degree of vial-sharing and administration costs. A probabilistic sensitivity analysis (PSA) was also conducted.

SETTING

Canadian publicly funded health-care system (Ministry of Health payer perspective) for base-case analysis. Societal perspective, accounting for future lost productivity, was adopted for a secondary analysis.

PARTICIPANTS

Canadian infants born at 32-35 weeks' GA without chronic lung disease.

INTERVENTIONS

Palivizumab prophylaxis versus no prophylaxis.

MAIN OUTCOME MEASURES

Expected costs and incremental cost-effectiveness ratio expressed as cost per life-year gained (LYG) and quality-adjusted life-year (QALY) using 2007 Canadian dollars.

RESULTS

The expected costs were higher for palivizumab prophylaxis as compared with no prophylaxis. The incremental cost-effectiveness ratio (ICER) for the base-case scenario was $20 924 per QALY after discounting, which is considered cost-effective in Canada. When the uncertainty of the input parameter assumptions was tested through sensitivity analyses assessing several data sources for five key parameters, no substantial differences were found from the base-case results. The PSA indicated a 0.99 probability that the ICER for palivizumab was less than $50 000/QALY. Sub-analyses that varied the number of risk factors found that for infants with two or more risk factors, or at least moderate risk, palivizumab had incremental costs per QALY that indicated moderate-to-strong evidence for adoption (range: $808-81 331, per QALY).

CONCLUSIONS

Palivizumab was cost-effective and the authors' model supports prophylaxis for infants born at 32-35 weeks' GA, particularly those with more than two risk factors or at least a moderate level of risk according to a risk scoring tool.

Clinical relevance of prevention of respiratory syncytial virus lower respiratory tract infection in preterm infants born between 33 and 35 weeks gestational age

Premature infants are vulnerable to severe respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) resulting in hospitalisation and the potential for longer-term respiratory morbidity. Whilst the severity and consequence of RSV LRTI are generally accepted and recognised in infants born <or=32 weeks gestational age (GA), there is less acknowledgment of the potential consequences in infants born 33-35 weeks GA. However, there is a growing body of evidence suggesting that infants born between 33 and 35 weeks GA may be equally at risk for RSV LRTI as infants born <32 weeks GA. Interrupted lung development and an immature immune system have been linked with an increased susceptibility for RSV LRTI, along with other environmental, social, and physiological risk factors. Currently, the only effective method of preventing RSV LRTI is prophylaxis with palivizumab. Often with limited healthcare resources, identifying infants at greatest risk of RSV LRTI who would potentially benefit most from prophylaxis is highly desirable, particularly in the 33-35-week GA group. The purpose of this article is to examine the causes and consequences of RSV LRTI in infants born 33-35 weeks GA, and look at the potential for using risk factors to identify high risk infants and, thereby, optimise prophylaxis. The causes and consequences of RSV LRTI in infants born 33-35 weeks GAA were determined via literature review. A number of underlying risk factors that significantly increase the risk of severe RSV LRTI and subsequent hospitalisation in this group of infants have been identified, most notably from the FLIP and PICNIC studies. A European predictive model based on the risk factors in the FLIP study has recently been developed and validated, which will aid identification of infants born between 33 and 35 weeks GA with the highest risk of RSV hospitalisation. Implementation of this model and prophylaxis of infants born between 33 and 35 weeks GA should be a national or regional decision, taken in perspective of other public health needs.

[Severe bronchiolitis. Epidemiology and clinical course of 284 patients]

INTRODUCTION

Bronchiolitis is the leading cause of hospital admission and a frequent cause of pediatric intensive care unit (PICU) admission among infants during the winter months. The objective of this study was to analyze the characteristics and clinical course of patients admitted to the PICU for bronchiolitis.

PATIENTS AND METHOD

We performed a descriptive, observational study by clinical chart review of all patients admitted to the PICU for severe bronchiolitis from November 1994 to March 2006.

RESULTS

A total of 284 patients were included. Most were admitted during December and January and 74% had respiratory syncytial virus (RSV) infection. At least one risk factor for severe disease was present in 68% of the patients: the most frequent risk factor was age < 6 weeks (45%), followed by prematurity (30%). Mechanical ventilation was required in 64 of the 284 patients (24%). Mortality was 1.8% and was associated with chronic pre-existing illness (p < 0.001). The factors associated with a greater risk of mechanical ventilation and a longer PICU stay were the association of two or more risk factors (42/284; 15%), the presence of apnea (73/284; 25.7%), and images of pulmonary consolidation or atelectasis on admission chest X-ray (157/284; 55%).

CONCLUSIONS

Most patients admitted for severe bronchiolitis to the PICU are healthy infants whose principal risk factor is young age. The main predictors of severe clinical course during PICU stay are the association of two or more risk factors, the presence of apnea, and pulmonary consolidation on admission chest X-ray. Bronchiolitis-associated mortality is low and is associated with pre-existing chronic illness.

Lung function in prematurely born infants after viral lower respiratory tract infections

BACKGROUND

Chronic respiratory morbidity has been reported in prematurely born infants after respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) lower respiratory tract infections (LRTIs). The aim of this study was to determine the impact of viral LRTI on lung function at follow-up of prematurely born infants.

METHODS

Fifty-nine infants born before 32 weeks of gestational age were prospectively followed after neonatal unit discharge. Nasopharyngeal aspirates were obtained when the infants developed LRTIs in hospital or the community. RSV was identified by immunofluorescence and/or culture. In addition, RSV and other viral infections were identified by real time reverse transcription polymerase chain reaction. At a corrected age of 1 year, measurements of lung volume [functional residual capacity (FRC)pleth] and airway resistance (R(aw)) were made by plethysmography, and lung volume was also assessed by helium gas dilution (FRC(He)). Before the measurements, parents completed diary cards for 1 month documenting on a daily basis whether their infant wheezed, coughed, or required bronchodilator therapy.

RESULTS

Twenty-five infants had at least 1 proven RSV LRTI (RSV-positive group). The RSV-positive group compared with the rest of the cohort had similar lung volumes, but significantly higher R(aw) (P = 0.002), more days of wheeze (P < 0.001), and bronchodilator requirement (P = 0.027). Regression analysis also identified that hMPV LRTI was associated with elevated airways resistance at follow-up.

CONCLUSION

RSV and hMPV LRTIs in prematurely born infants are associated with abnormal lung function at follow-up.

Diagnostic virology practices for respiratory syncytial virus and influenza virus among children in the hospital setting: a national survey

A survey was sent to the emergency room and laboratory directors of 400 randomly selected US hospitals to assess the diagnostic testing practices for respiratory syncytial virus and influenza virus in children. The results demonstrate that the majority of hospitals routinely perform viral testing for both viruses and use virology testing practices appropriate for the reasons reported for testing.

Human bocavirus infection, People's Republic of China

A newly identified parvovirus, human bocavirus (HBoV), was found in 21 (8.3%) of 252 nasopharyngeal aspirates from hospitalized children with lower respiratory tract infection in Hunan Province, People’s Republic of China. Viral loads were 10⁴ to 10¹⁰ copies/mL. Phylogenetic analysis of the VP1 gene showed a single genetic lineage of HBoV worldwide.

Human bocavirus infection, People's Republic of China

A newly identified parvovirus, human bocavirus (HBoV), was found in 21 (8.3%) of 252 nasopharyngeal aspirates from hospitalized children with lower respiratory tract infection in Hunan Province, People's Republic of China. Viral loads were 10(4) to 10(10) copies/mL. Phylogenetic analysis of the VP1 gene showed a single genetic lineage of HBoV worldwide.

Immunopathology of RSV infection: prospects for developing vaccines without this complication

Respiratory syncytial virus is the most important cause of lower respiratory tract infection in infants and young children. RSV clinical disease varies from rhinitis and otitis media to bronchiolitis and pneumonia. An increased incidence of asthma later in life has been associated with the more severe lower respiratory tract infections. Despite its importance as a pathogen, there is no licensed vaccine against RSV. This is due to a number of factors complicating the development of an effective and safe vaccine. The immunity to natural RSV infection is incomplete as re-infections occur in all age groups, which makes it challenging to design a protective vaccine. Second, the primary target population is the newborn infant, which has a relatively immature immune system and maternal antibodies that can interfere with vaccination. Finally, some vaccines have resulted in a predisposition for exacerbated pulmonary disease in infants, which was attributed to an imbalanced Th2-biased immune response, although the exact cause has not been elucidated. This makes it difficult to proceed with vaccine testing in infants. It is likely that an effective and safe vaccine needs to elicit a balanced immune response, including RSV-specific neutralising antibodies, CD8 T-cells, Th1/Th2 CD4 T-cells and preferably secretory IgA. Subunit vaccines formulated with appropriate adjuvants may be adequate for previously exposed individuals. However, intranasally delivered genetically engineered attenuated or vectored vaccines are currently most promising for newborns, as they are expected to induce a balanced immune response similar to that elicited to natural infection and not be subject to interference from maternal antibodies. Maternal vaccination may be the optimal strategy to protect the very young infants.

[The efficiency (cost-effectiveness) of palivizumab as prophylaxis against respiratory syncytial virus infection in premature infants with a gestational age of 32-35 weeks in Spain]

OBJECTIVES

To evaluate the efficiency (cost-effectiveness) of palivizumab in preventing severe respiratory syncytial virus (RSV) infection in premature infants with a gestational age of 32-35 weeks (GA 32-35) and two or more risk factors (RF) in Spain.

METHODS

DESIGN

decision tree model using data from the scientific literature and the FLIP I and FLIP II studies (cohort of 326 infants with GA 32-35 and two or more RF who received palivizumab) sponsored by the Spanish Society of Neonatology. Main effectiveness measure: quality-adjusted life years (QALY) gained.

PERSPECTIVES

the national health service (NHS), which includes direct costs (administration of palivizumab and hospital admissions), and the societal perspective, which also includes indirect costs (the child's future lost productivity). Discount: 3 % annually for effectiveness and indirect costs. Sensitivity analysis: construction of 37 scenarios modifying variables related to effectiveness and costs.

RESULTS

Prophylaxis with palivizumab in premature infants with GA 32-35 and two or more RF produced an incremental cost-effectiveness ratio (ICER) of 13,849 euro/QALY from the NHS perspective, and an ICER of 4,605 euro/QALY from the societal perspective. In the sensitivity analysis, from the NHS perspective the ICER ranged from 5,351 euro/QALY (most favorable scenario) to 23,276 euro/QALY (least favorable scenario).

CONCLUSIONS

Palivizumab is a cost-effective therapy as prophylaxis against RSV in infants with GA 32-35 and two or more RF. Its use is efficient from the NHS perspective, since the cost of a QALY, even in the least favorable scenarios, is lower than the threshold of 30,000 Euro/QALY considered socially acceptable in Spain.

Beyond randomized controlled trials: a "real life" experience of respiratory syncytial virus infection prevention in infancy with and without palivizumab

A population-based study of the impact of palivizumab on confirmed Respiratory Syncytial Virus (RSV) hospitalizations over a 7-year period within and between two similar health regions . Clinicians in Calgary implemented palivizumab prophylaxis for high-risk infants during the last four RSV seasons; clinicians in Edmonton did not. The two cities are part of a unified health care system and similar sociodemographics. Infants <36 weeks (wk) of gestational age (GA) were identified. RSV prophylaxis data and RSV-hospitalizations for high-risk infants eligible for prophylaxis were reviewed, as well as that of moderate-risk infants (33-35 weeks GA) for whom RSV prophylaxis was not given a high priority in the recommendations published by the Canadian Paediatric Society (CPS). Prevalence of RSV hospitalization before and after palivizumab was determined (1995-1998 and 1999-2002, respectively). There were 411 high-risk infants eligible for palivizumab prior to its provision (Pre) and 496 during the prophylaxis program (Post) in Calgary. There were 401 Pre and 425 Post in Edmonton, where no such prophylaxis program was implemented. In Calgary where palivizumab was offered (Post), RSV hospitalization was significantly reduced: 7.3% Pre versus 3.0% Post (OR, 2.53, 95% CI, 1.34, 4.76). No reduction was observed in Edmonton where palivizumab was not offered: 5.0% Pre versus 7.1% Post (OR, 1.45, 95% CI, 0.81, 2.59; P = 0.212). RSV hospitalizations did not change for moderate-risk infants not receiving palivizumab in Calgary (OR, 1.26, 95% CI, 0.75, 2.12; P = 0.389). An RSV prevention program with palivizumab for high-risk infants reduced RSV hospitalizations, providing "real life" evidence of the benefits of this prophylaxis strategy. Further research is required to determine if specific sub-sets of moderate-risk infants would also benefit from an RSV prophylaxis program with palivizumab.

[Recommendations for the prevention of respiratory syncytial virus infection]

Premature babies < or = 35 weeks gestation, with or without chronic lung disease (CLD), and infants affected by severe congenital heart disease should be considered high risk population for RSV infection and hospitalization. Hygienic measures and RSV monoclonal antibodies (palivizumab) have been found useful in decreasing rates of RSV hospitalization in these patients. Guidelines for their administration include: a) strongly recommended use in premature babies < or = 28 weeks gestation, or born between 29-32 weeks gestation and less than 6 months at start of RSV station or discharged along it, or affected by CLD in treatment during last 6 months or by severe congenital heart disease. Last two groups could be prophylaxed for two RSV seasons. b) Recommended use among premature babies between 32-35 weeks gestation and less than 6 months of age and presenting two or more risk factors: chronologic age < 10 weeks at start of RSV station, breastfeeding < or = 2 months (physician prescription), sibling < 14 years old, day-care assistance, family history of wheezing, > or = 4 adults at home, airways malformation or neuromuscular disease.

Diagnosis coding in The Danish National Patient Registry for respiratory syncytial virus infections

This national registry-based epidemiological study aimed to evaluate the usefulness of the Danish National Patient Registry (DNPR) as a tool for epidemiological studies of respiratory syncytial virus (RSV) hospitalizations. Information on RSV diagnoses in records of hospitalizations among inpatients tested for RSV in Denmark from January 1996 to May 2003 in the DNPR was validated against the RSV test result in records from the 18 laboratories testing for RSV among hospitalized patients in Denmark. Of 16,733 RSV-positive samples representing a total of 14,898 hospitalizations in the DNPR, 68% (10,111) had been registered in the DNPR with 1 or more RSV diagnoses. Age influenced the odds ratio (OR) of being coded with a RSV diagnosis among patients with a RSV positive test, hence 73% of infants compared to 57% of patients beyond infancy had been registered in the DNPR with 1 or more RSV diagnoses. The OR of being coded with a RSV diagnosis among patients with an RSV positive test was increased over the study period and was also increased by increasing length of hospitalization and by the presence of secondary diagnoses. The OR was decreased by the presence of asthma and other chronic conditions in the patients. The OR was furthermore influenced by RSV seasonality and by hospital. Taking into account a loss of 27% of RSV hospitalizations, DNPR can be used for epidemiological studies of RSV among infants in Denmark.

Chronic manifestations of respiratory syncytial virus infection in premature infants

BACKGROUND

Respiratory syncytial virus (RSV) infection in healthy infants born at term results in long term sequelae. Infants born prematurely are at increased risk of severe acute RSV infection; thus it would seem likely that such infants would be at increased risk of long term respiratory sequelae.

METHODS

Methods of assessing the long term outcome of RSV infection are discussed and the results of retrospective and prospective studies investigating chronic respiratory morbidity after RSV infection in premature infants are reviewed.

RESULTS

Documentation of all health care utilization, parental documentation of symptom status and lung function measurement provide a comprehensive and quantitative assessment of respiratory outcome. Studies that have included such outcome measures have demonstrated that RSV hospitalization in infants born between 32 and 35 weeks of gestational age and in those born more prematurely who developed chronic lung disease was associated with more hospital admissions, inpatient days, physician contacts and outpatient visits in the first 2 years after birth. Children born before 32 weeks of gestation who developed chronic lung disease also required more outpatient attendances and prescriptions and respiratory medications in years 2 through 4. Prospective data collection has demonstrated that chronic respiratory morbidity occurs in very premature infants, regardless of whether their RSV infection required hospitalization.

CONCLUSION

Chronic respiratory morbidity is increased in premature infants after RSV infection. The duration of this increased morbidity and the impact of other viral infections, particularly dual infection with RSV, on long term sequelae merit investigation.

Prospective study of healthcare utilisation and respiratory morbidity due to RSV infection in prematurely born infants

BACKGROUND

A study was undertaken to determine the impact of respiratory syncytial virus (RSV) infection, both in hospital and the community, on healthcare utilisation and respiratory morbidity in prematurely born infants and to identify risk factors for symptomatic RSV infection.

METHODS

A hospital and community follow up study was undertaken of 126 infants born before 32 weeks of gestational age. Healthcare utilisation (hospital admissions and general practitioner attendances) in the first year, respiratory morbidity at follow up (wheeze and cough documented by parent completed diary cards), and RSV positive lower respiratory tract infections (LRTIs) were documented. Nasopharyngeal aspirates were obtained for immunofluorescence and culture for RSV whenever the infants had an LRTI, either in the community or in hospital.

RESULTS

Forty two infants had an RSV positive LRTI (RSV group), 50 had an RSV negative LRTI (RSV negative LRTI group), and 32 infants had no LRTI (no LRTI group). Compared with the RSV negative LRTI and the no LRTI groups, the RSV group required more admissions (p=0.392, p<0.001) and days in hospital (p=0.049, p=0.006) and had more cough (p=0.05, p=0.038) and wheeze (p=0.003, p=0.003) at follow up. Significant risk factors for symptomatic RSV LRTI were number of siblings (p=0.035) and maternal smoking in pregnancy (p=0.005), for cough were number of siblings (p=0.002) and RSV LRTI (p=0.02), and for wheeze was RSV LRTI (p=0.019).

CONCLUSION

RSV infection, even if hospital admission is not required, is associated with increased subsequent respiratory morbidity in prematurely born infants.

Immune responses and disease enhancement during respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is one of the commonest and most troublesome viruses of infancy. It causes most cases of bronchiolitis, which is associated with wheezing in later childhood. In primary infection, the peak of disease typically coincides with the development of specific T- and B-cell responses, which seem, in large part, to be responsible for disease. Animal models clearly show that a range of immune responses can enhance disease severity, particularly after vaccination with formalin-inactivated RSV. Prior immune sensitization leads to exuberant chemokine production, an excessive cellular influx, and an overabundance of cytokines during RSV challenge. Under different circumstances, specific mediators and T-cell subsets and antibody-antigen immune complex deposition are incriminated as major factors in disease. Animal models of immune enhancement permit a deep understanding of the role of specific immune responses in RSV disease, assist in vaccine design, and indicate which immunomodulatory therapy might be beneficial to children with bronchiolitis.

Bronchiolitis: in-patient focus

Bronchiolitis is among the most common and serious lower respiratory tract syndromes that affects young children. In developed countries, the case fatality rate among previously healthy children remains low; in contrast, infants with underlying medical conditions, such as immunodeficiency or chronic lung disease, are at risk of prolonged illness and death. Bronchiolitis is associated with significant morbidity among healthy young children. During the winter season, bronchiolitis is the most common cause of hospitalization among infants. Each year in the United States, approximately 2 per 100,000 infants die as a result of complications associated with bronchiolitis.

Palivizumab for preterm infants. Is it worth it?

Respiratory syncytial virus infection is an important cause of morbidity. Although palivizumab prophylaxis is widely used, it is uncertain whether the cost is justified. A systematic review was therefore performed of the safety, efficacy, and the likely cost effectiveness of prophylaxis for preterm infants in the United Kingdom using a standard search strategy. The only randomised controlled trial identified showed a reduction in hospital admission but no benefit on more serious outcomes. None of the United Kingdom cost studies showed economic benefit for palivizumab prophylaxis. New treatments are rarely cost effective, and, in the absence of a comprehensive economic assessment, continued use for high risk infants may appear justified.

Dexamethasone inhalations in RSV bronchiolitis: a double-blind, placebo-controlled study

OBJECTIVE

To evaluate the effect of inhaled dexamethasone on hospitalization for respiratory syncytial virus (RSV) bronchiolitis.

STUDY DESIGN

A double-blind, placebo-controlled study compared nebulization of dexamethasone versus nebulization of 0.9% saline. Both groups were treated with epinephrine nebulizations. Follow-up continued for 3 mo.

PATIENTS AND METHODS

Sixty-one infants with bronchiolitis aged 3 to 12 mo were included. They were randomly allocated to nebulizations with 0.25 mg dexamethasone every 6 h (group 1) or an equivalent amount of normal saline (group 2).

RESULTS

No statistically significant differences with respect to clinical score, oxygen saturation, or IV fluid requirement between the groups were noted. Using Kaplan-Meyer's method, the cumulative proportion of in-hospital stay was significantly lower in group 1 compared with group 2, mainly in days 5 and 6 post-hospitalization (p<0.038). A subgroup of prematurely born children in group 1 had a shorter hospitalization period (6.5+/-1.7 d) compared with group 2 children (9.1+/-1.9) (p<0.018). Follow-up revealed similar wheeze and hospitalization rates in the two groups.

CONCLUSION

Inhaled dexamethasone may reduce the length of hospitalization among infants with acute viral bronchiolitis, especially among those born prematurely.

Palivizumab: a review of its use as prophylaxis for serious respiratory syncytial virus infection

Palivizumab (Synagi) is a humanized monoclonal antibody that provides immunoprophylaxis against serious lower respiratory tract infections (LRTIs) caused by respiratory syncytial virus (RSV). RSV is the leading cause of hospitalization for LRTIs in infants, causing winter- or wet-season epidemics. In two double-blind, placebo-controlled trials, intramuscular palivizumab 15 mg/kg every 30 days for 5 months significantly reduced RSV-related hospitalizations by 55% in 1502 infants with prematurity and/or bronchopulmonary dysplasia/chronic lung disease (BPD/CLD) and by 45% in 1287 infants with hemodynamically significant congenital heart disease (HSCHD). Reductions were statistically significant versus placebo in infants with BPD/CLD, with all degrees of prematurity, and with acyanotic/other heart disease. Palivizumab was generally well tolerated, with < or =1.9% of recipients discontinuing treatment for tolerability reasons. In placebo-controlled trials, the most common potentially drug-related adverse events were fever, nervousness, injection-site reactions, and diarrhea. Drug-related events occurred in 7.2-11% of palivizumab recipients in controlled trials (vs 6.9-10% with placebo) and 0-7.9% in open-label trials. Very few serious potentially drug-related adverse events occurred in clinical trials; four occurred in 2 of 285 patients in one open-label trial. No significant anti-palivizumab antibodies developed during palivizumab use. Palivizumab trough serum concentrations were below the recommended 40 microg/mL in about 33% and up to 14% of children prior to their second and third palivizumab injections. In pharmacoeconomic studies, the cost of palivizumab per hospitalization averted was generally lowest in the highest-risk infants. Drug cost was generally the most influential factor in sensitivity analyses. In conclusion, prophylaxis with palivizumab significantly reduces the incidence of RSV-related hospitalization relative to placebo and is generally well tolerated in high-risk infants aged <2 years, including those with prematurity and BPD/CLD or HSCHD, which are risk factors for early or serious RSV infection. Palivizumab is approved for use in these patients. Other high-risk infants in whom palivizumab has not been formally assessed, such as those with immunodeficiency, cystic fibrosis, or location-specific risk factors (including extended hospital stays) might potentially benefit from palivizumab. The use of palivizumab in these other high-risk populations is likely to be determined as much by pharmacoeconomic considerations as by efficacy outcomes.