Costs and benefits of respiratory syncytial virus immunoglobulin to prevent hospitalization for lower respiratory tract illness in very low birth weight infants

Respiratory syncytial virus prevention and therapy: past, present, and future

Respiratory syncytial virus (RSV) is the most common respiratory pathogen in infants and young children worldwide. More than 50 years after its discovery, and despite relentless attempts to identify pharmacological therapies to improve the clinical course and outcomes of this disease, the most effective therapy remains supportive care. Although the quest for a safe and effective vaccine remains unsuccessful, pediatricians practicing during the past decade have been able to protect at least the more vulnerable patients with safe and effective passive prophylaxis. This review summarizes the history, microbiology, epidemiology, pathophysiology, and clinical manifestations of this infection in order to provide the reader with the background information necessary to fully appreciate the many challenges presented by the clinical management of young children with bronchiolitis. The last part of this article attempts an evidence-based review of the pharmacologic strategies currently available and those being evaluated, intentionally omitting highly experimental approaches not yet tested in clinical trials and, therefore, not likely to become available in the foreseeable future.

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.

Epidemiology

The common cold is the result of an upper respiratory tract infection causing an acute syndrome characterised by a combination of non-specific symptoms, including sore throat, cough, fever, rhinorrhoea, malaise, headache, and myalgia. Respiratory viruses, alone or in combination, are the most common cause. The course f illness can be complicated by bacterial agents, causing pharyngitis or sinusitis, but the are a rare cause of cold and flu-like illnesses (CFLIs). Our understanding of CFLI epidemiology has been enhanced by molecular detection methods, particularly polymerase chain reaction (PCR) testing. PCR has not only improved detection of previously known viruses, but within the last decade has resulted in the detection of many divergent novel respiratory virus species. Human rhinovirus (HRV) infections cause nearly all CFLIs and they can be responsible for asthma and chronic obstructive pulmonary disease exacerbations. HRVs are co-detected with other respiratory viruses in statistically significant patterns, with HRVs occurring in the lowest proportion of co-detections, compared to most other respiratory viruses. Some recently identified rhinoviruses may populate an entirely new putative HRV species; HRV C. Further work is required to confirm a causal role for these newly identified viruses in CFLIs. The burden of illness associated with CFLIs is poorly documented, but where data are available, the impact of CFLIs is considerable. Individual infections, although they do not commonly result in more severe respiratory tract illness, are associated with substantial direct and indirect resource use. The product of frequency and burden for CFLIs is likely to be greater in magnitude than for any other respiratory syndrome, but further work is required to document this. Our understanding of the viral causes of CLFIs, although incomplete, has improved in recent years. Documenting burden is also an important step in progress towards improved control and management of these illnesses.

WITHDRAWN: Immunoglobulin for preventing respiratory syncytial virus infection

BACKGROUND

Respiratory Syncytial virus, the most important cause of lower respiratory tract infections in infants and young children in industrialized countries, is associated with increased morbidity in premature infants with or without bronchopulmonary dysplasia as well as those with congenital heart disease. Because of observations that lower rates of disease occur immediately after birth, presumably due to vertical transmission of maternal antibody, and animal studies where protection from pneumonia was observed through administration of immune globulin, the efficacy of passive prophylaxis in premature infants has been studied.

OBJECTIVES

This meta-analysis was performed to assess the effects of polyclonal respiratory syncytial virus hyperimmune globulin or monoclonal antibody in preventing RSV hospitalization, receipt of intensive care, mechanical ventilation, and mortality in those with underlying prematurity, bronchopulmonary dysplasia, or congenital heart disease.

SEARCH STRATEGY

We searched the Cochrane Acute Respiratory Infections trials register and MEDLINE in March, 1999. In addition, abstracts on these topics were sought from the Pediatric Academies Meetings and the Intersciences Conference on Antimicrobial Agents and Chemotherapy for the years 1994 to 1997, inclusive.

SELECTION CRITERIA

Randomized, controlled trials of prevention of RSV using immune globulin, respiratory syncytial virus immune globulin, or monoclonal RSV antibody in children with prematurity, bronchopulmonary dysplasia or congenital heart disease.

DATA COLLECTION AND ANALYSIS

Two authors independently abstracted data and assessed study quality. Only incidences could be pooled because data for durations was summarized in a manner that did not allow combining results across the studies.

MAIN RESULTS

Four studies with a total of 2598 subjects were included in the main analysis. All were randomized controlled trials. Two trials were not blinded. Three studies examined RSV hyperimmune globulin and one examined monoclonal RSV antibody. A study of a different monoclonal RSV antibody could not be included because it has not been presented or published. The pooled Peto Odds Ratios favoring prophylaxis were 0.48 (95% CI 0.37, 0.64), 0.47 (0.29, 0.77), and 0.99 (0.48, 2.07) for incidence of hospitalization, incidence of ICU admission, and incidence of mechanical ventilation, respectively. The numbers needed to prevent one hospitalization and one ICU admission are 17 and 50 respectively.

AUTHORS' CONCLUSIONS

RSVIG is effective in preventing RSV hospitalizations and admission to the intensive care unit, but not in preventing mechanical ventilation. There was a non-significant trend towards a higher mortality in children given RSVIG.

Diagnosis and management of bronchiolitis

Bronchiolitis is a disorder most commonly caused in infants by viral lower respiratory tract infection. It is the most common lower respiratory infection in this age group. It is characterized by acute inflammation, edema, and necrosis of epithelial cells lining small airways, increased mucus production, and bronchospasm. The American Academy of Pediatrics convened a committee composed of primary care physicians and specialists in the fields of pulmonology, infectious disease, emergency medicine, epidemiology, and medical informatics. The committee partnered with the Agency for Healthcare Research and Quality and the RTI International-University of North Carolina Evidence-Based Practice Center to develop a comprehensive review of the evidence-based literature related to the diagnosis, management, and prevention of bronchiolitis. The resulting evidence report and other sources of data were used to formulate clinical practice guideline recommendations. This guideline addresses the diagnosis of bronchiolitis as well as various therapeutic interventions including bronchodilators, corticosteroids, antiviral and antibacterial agents, hydration, chest physiotherapy, and oxygen. Recommendations are made for prevention of respiratory syncytial virus infection with palivizumab and the control of nosocomial spread of infection. Decisions were made on the basis of a systematic grading of the quality of evidence and strength of recommendation. The clinical practice guideline underwent comprehensive peer review before it was approved by the American Academy of Pediatrics. This clinical practice guideline is not intended as a sole source of guidance in the management of children with bronchiolitis. Rather, it is intended to assist clinicians in decision-making. It is not intended to replace clinical judgment or establish a protocol for the care of all children with this condition. These recommendations may not provide the only appropriate approach to the management of children with bronchiolitis.

Anticipated costs of hospitalization for respiratory syncytial virus infection in young children at risk

BACKGROUND

Reliable estimates of hospitalization costs for severe respiratory syncytial virus (RSV) infection are necessary to perform economic analyses of preventive strategies of severe RSV disease. We aimed to develop a model that predicts anticipated mean RSV hospitalization costs of groups of young children at risk for hospitalization, but not yet hospitalized, based on readily available child characteristics.

METHODS

We determined real direct medical costs of RSV hospitalization from a societal perspective, using a bottom-up strategy, in 3458 infants and young children hospitalized for severe RSV disease during the RSV seasons 1996-1997 to 1999-2000 in the Southwest of the Netherlands. We used a linear regression model to predict anticipated mean RSV hospitalization costs of groups of children at risk, based on 4 child characteristics [age, gestational age, birth weight and bronchopulmonary dysplasia (BPD)], expressed in EC Euros as of the year 2000.

FINDINGS

The mean RSV hospitalization costs of all patients were 3110 Euros. RSV hospitalization costs were higher for patients with lower gestational age (5555 Euros; gestational age, </=28 weeks), lower birth weight (3895 Euros; birth weight </=2500 g), BPD (5785 Euros; with BPD) and young age (4730 Euros; first month of life). The linear regression model had an adjusted R of 0.08. This indicates a low explanatory ability for hospitalization costs of individual children. However, the model could accurately estimate the anticipated mean hospitalization costs of groups of children with the same characteristics.

INTERPRETATION

RSV hospitalization costs were substantial, especially of specific high risk groups. Anticipated mean hospitalization costs of groups of children at risk for RSV hospitalization, but not yet hospitalized, could well be estimated with 4 child characteristics (age, gestational age, birth weight and BPD). These estimated costs can be used for economic analyses of preventive strategies for severe RSV disease.

Revised indications for the use of palivizumab and respiratory syncytial virus immune globulin intravenous for the prevention of respiratory syncytial virus infections

Palivizumab and Respiratory Syncytial Virus Immune Globulin Intravenous (RSV-IGIV) are licensed by the Food and Drug Administration for use in preventing severe respiratory syncytial virus (RSV) infections in high-risk infants, children younger than 24 months with chronic lung disease (formerly called bronchopulmonary dysplasia), and certain preterm infants. This report summarizes the clinical trial information on which the guidance in the accompanying policy statement for administering RSV prophylaxis to certain children with a history of preterm birth, chronic lung disease, or congenital heart disease is based. On the basis of results of a recently completed clinical trial, palivizumab is appropriate for infants and young children with hemodynamically significant congenital heart disease. RSV-IGIV should not be used in children with hemodynamically significant heart disease. Palivizumab is preferred for most high-risk infants and children because of ease of intramuscular administration. Monthly administration of palivizumab during the RSV season results in a 45% to 55% decrease in the rate of hospitalization attributable to RSV. Because of the large number of infants born after 32 to 35 weeks' gestation and because of the high cost, immunoprophylaxis should be considered for this category of preterm infants only if 2 or more risk factors are present.

Follow-up data their use in evidence-based decision-making

Experience with certain perinatal interventions, such as supplemental oxygen and dexamethasone, leads to the conclusion that follow-up data are needed to be well informed about the safety of certain perinatal interventions. Experience with indomethacin suggests that follow-up data also are regarded by some clinicians as a necessary aspect of evidence about effectiveness. Ideally, clinical trials of perinatal interventions might involve collection of data about neonatal predictors of outcome (such as a neuroimaging study and a standardized neurologic assessment); several developmental and neurologic assessments before school entry; a comprehensive evaluation of the child's cognitive function, behavioral competencies, and academic performance at 7 to 8 years of age; serial detailed assessments of the family psychosocial functioning; and an inventory of resources available for the child. Many clinical trials have not included follow-up after the neonatal period, and in such cases information about the effect of the intervention on participants' HRQL is incomplete. The approach taken in several recent trials, in which the outcome of interest is neurodevelopmental outcome at 18 months, attempts to strike a balance between a theoretical ideal (a comprehensive, longitudinal follow-up through school age) and a follow-up regimen that is not prohibitively expensive. Such trials include follow-up during the first 1 to 3 years of life, when major disabilities can be identified reliably, thereby providing moderately informative data about participants' eventual quality of life, related to the presence or absence of major disability. If, however, there is reason to suspect that the intervention has effects on the developing brain, follow-up after school entry may provide additional evidence pertinent to the risks and benefits of the intervention.

Current strategies in the prevention of respiratory syncytial virus disease

Infants infected with respiratory syncytial virus (RSV) develop both upper and lower respiratory tract infections resulting in laryngotracheobronchitis, bronchiolitis and pneumonia. Premature infants of less than 32 weeks' gestation and those with underlying chronic lung disease are particularly susceptible and incur significant morbidity and mortality following hospitalisation. Conservative RSV prevention strategies focus on the interruption of transmission by proper hand-washing techniques and reducing exposure to potential environmental risk factors. Major challenges have impeded the development of an RSV vaccine but a licensed product may be expected in the near future. Prophylaxis with a humanised mouse monoclonal antibody (palivizumab) has been effective in reducing the rate of RSV hospitalisation in high-risk premature infants in phase II-IV trials and is available for use within internationally approved guidelines. Experimental studies evaluating the use of palivizumab in patients with congenital heart disease, those with cystic fibrosis and immunosuppressed bone marrow transplant recipients are well underway, the results of which are eagerly awaited.

Parental emotional and time costs predict compliance with respiratory syncytial virus prophylaxis

BACKGROUND

Two agents are effective in preventing respiratory syncytial virus (RSV) hospitalization in premature infants: RSV immune globulin (RSV-IG) and palivizumab. RSV-IG is associated with greater parental emotional and time costs, which may account for the more limited adherence to recommended monthly treatment with this agent.

OBJECTIVES

To compare the emotional distress and time costs associated with RSV-IG and palivizumab treatments and to determine the influence of these costs on treatment adherence.

METHODS

We surveyed parents of 82 infants who received RSV-IG (90% of eligible) and parents of 61 infants who received palivizumab (87% of eligible) at Arkansas Children's Hospital by telephone. We measured infant distress during treatment, parental distress, parental time costs, and adherence with recommended monthly prophylaxis.

RESULTS

Half of parents of RSV-IG recipients witnessed their infant in distress during infusion, over half (61%) were upset by observing the needle stick, and 22% observed infusion in the scalp. Fewer than 5% of parents of palivizumab recipients observed their infant in distress or were themselves distressed during treatment. A quarter of parents took time off from work for RSV-IG or palivizumab treatment. RSV-IG recipients completed 62% of recommended monthly treatments compared with 86% completed by palivizumab recipients. Increased parental distress and time costs largely accounted for the reduction in adherence to monthly treatment among RSV-IG recipients.

CONCLUSIONS

The emotional and time costs of RSV-IG treatment far exceed those of palivizumab and predict substantial differences in treatment adherence between the 2 agents. The impact of hidden costs on treatment adherence should be included in economic evaluations of medical procedures.

Respiratory syncytial virus prophylaxis: cost-effective analysis in Argentina

INTRODUCTION

Respiratory syncytial virus is a major cause of bronchiolitis during the first year of life. Preterm infants and patients with bronchopulmonary dysplasia (BPD) have a higher risk of hospitalization. The objective of this study was to assess the risk of hospitalization and to evaluate the cost effectiveness of palivizumab use in our at risk population.

METHODS

The study design was based on the hypothetical use of palivizumab in a cohort of patients. The cost effectiveness analysis included costs of palivizumab, the drug prescription and hospitalization. The effectiveness measure was the hospitalization rate decrease according to the result of the IMpact study: a 55% reduction in the need for hospitalization attributable to RSV. The years 1998 and 1999 were analyzed. Evaluable patients had follow-up at the High Risk Clinic and fulfilled the American Academy of Pediatrics criteria for palivizumab prophylaxis.

RESULTS

Forty-two patients, 24 with BPD and 18 preterm infants without BPD, were evaluated. Ten patients required hospitalization because of respiratory syncytial virus; one of them died. Hospitalization cost was $184,777. The total palivizumab administration cost would have been $185,064. With a 55% decrease of hospitalization rate, the cost per hospitalization averted would have been $15,358, and the number needed to treat would have been 7.9. A sensitivity analysis showed that the cost per hospitalization averted could range between $2,171 and $48,630 according to the hospitalization rate.

CONCLUSIONS

Because new effective but expensive treatments like palivizumab are available, this cost effective analysis can be an important tool in decisions about resource distribution.

Prevention of respiratory syncytial virus infections

Respiratory syncytial virus is the most important cause of viral lower respiratory illness in infants and children worldwide. By the age of 2 years, nearly every child has become infected with respiratory syncytial virus and re-infections are common throughout life. Most infections are mild and can be managed at home, but this virus causes serious diseases in preterm children, especially those with bronchopulmonary dysplasia. Respiratory syncytial virus has also been recognized as an important pathogen in people with immunossupressive and other underlying medical problems and institutionalizated elderly, causing thousands of hospitalizations and deaths every year. The burden of these infections makes the development of vaccines for respiratory syncytial virus highly desirable, but the insuccess of a respiratory syncytial virus formalin-inactivated vaccine hampered the progress in this field. To date, there is no vaccine available for preventing respiratory syncytial virus infections, however, in the last years, there has been much progress in the understanding of immunology and immunopathologic mechanisms of respiratory syncytial virus diseases, which has allowed the development of new strategies for passive and active prophylaxis. In this article, the author presents a review about novel approaches to the prevention of respiratory syncytial virus infections, such as: passive immunization with human polyclonal intravenous immune globulin and humanized monoclonal antibodies (both already licensed for use in premature infants and children with bronchopulmonary dysplasia), and many different vaccines that are potential candidates for active immunization against respiratory syncytial virus.

Recent advances in the management and prophylaxis of respiratory syncytial virus infection

Respiratory syncytial virus (RSV) infection is an important cause of morbidity, particularly in prematurely born infants who have had chronic lung disease. Current therapy is essentially supportive. Overall, the results of randomized trials do not support the use of bronchodilators, corticosteroids or Ribavirin. Nitric oxide and exogenous surfactant may improve the respiratory status of those infants who require ventilatory support. Nosocomial infection can be reduced by appropriate handwashing. There is no safe and effective vaccine for use in infants. Immunoprophylaxis reduces hospitalization and requirement for intensive care. Palivizumab, a humanized monoclonal antibody, is preferred to RSV immune globulin as the immunoprophylactic agent. Immunoprophylaxis should be reserved for infants at highest risk of severe respiratory syncytial virus infection, if this strategy is to be used most cost-effectively.

Economic impact of influenza vaccination in preschool children

OBJECTIVE

The economic impact of routine vaccination of preschool children with inactivated influenza vaccine was investigated.

DESIGN

A decision analysis was performed using data from the literature. Direct and indirect costs of each vaccination strategy were calculated and compared with a strategy of not vaccinating.

SETTING

Two settings were evaluated: a setting in which vaccination was available during flexible hours and a setting in which vaccination was available only during usual work hours (8:00 am-5:00 pm).

RESULTS

Vaccination resulted in a net cost savings in both settings. The net savings per vaccine recipient were $21.28 in the flexible setting and $1.20 in the restricted setting. Although the analysis was performed for the inactivated vaccine, sensitivity analysis showed that the nasal vaccine could also result in a net cost savings depending on the price of the cold-adapted vaccine when it is licensed.

CONCLUSION

Vaccinating preschool children is economically advantageous. Serious consideration should be given to recommending vaccination in this age group.

Respiratory syncytial virus pneumonia in the hospital setting: length of stay, charges, and mortality

BACKGROUND

Respiratory syncytial virus (RSV) is the most important viral cause of lower respiratory tract infection in infants and young children worldwide. No vaccine against RSV is available, but prophylactic interventions have been shown to be safe and effective in clinical trials.

OBJECTIVES

This retrospective analysis was conducted to examine the health and economic burden of hospitalization for RSV pneumonia.

METHODS

Nationally weighted hospital discharges for RSV pneumonia among children 4 years old and younger were analyzed by using the Healthcare Cost and Utilization Project National Inpatient Sample.

RESULTS

In 1993, there were estimated to be 16,500 hospital discharges with RSV pneumonia, which increased to 19,700 and 20,800 in 1994 and 1995, respectively. Children less than 1 year of age accounted for over 70% of these discharges. Hospital charges (in 1998 dollars) for RSV pneumonia-associated episodes were $295,100,000 in 1993; $392,300,000 in 1994; and $295,800,000 in 1995.

CONCLUSIONS

With inpatient charges of $300 to $400 million per year in the United States, the disease burden of RSV pneumonia is very high in terms of both morbidity and economic costs. Emerging prophylactic interventions should have an impact on the high burden of RSV pneumonia.

Prophylaxis for respiratory syncytial virus with respiratory syncytial virus-immunoglobulin intravenous among preterm infants of thirty-two weeks gestation and less: reduction in incidence, severity of illness and cost

OBJECTIVE

To determine the impact of respiratory syncytial virus (RSV) prophylaxis among preterm infants of < or =32 weeks gestation by comparing the severity of illness and cost of RSV-related care during the two winter seasons before (1994 to 1995, 1995 to 1996) with the two seasons after initiation of prophylaxis (1996 to 1997, 1997 to 1998).

METHODS

Preterm infants of < or =32 weeks gestation at risk for hospitalization with RSV infection were identified retrospectively from the infants hospitalized in our neonatal units. Infants were included if they (1) were born 6 months before or during four winter seasons (1994 to 1998), (2) were discharged from the neonatal unit and (3) had remained in the university outpatient clinic system during at least the first winter of life. Preterm infants of < or =32 weeks gestation hospitalized with RSV were identified from our RSV database (which includes cost of hospitalization, duration of hospital stay, pediatric intensive care unit stay and intubation). Infants receiving prophylaxis were identified prospectively.

RESULTS

The incidence of hospitalization with RSV was significantly lower among the cohort of infants born after initiation of prophylaxis: 8.7% (17 of 195) vs. 22% (35 of 159), P = 0.00049 by two tailed Fisher's exact test. Among the cohort of infants born after initiation of prophylaxis (n = 195), 100 infants received prophylaxis. The gestational and chronologic ages of the prophylaxis-treated infants were significantly lower than those of the non-prophylaxis-treated infants (n = 95). The prophylaxis-treated infants also were more likely to have bronchopulmonary dysplasia. Only 1 (1%) of the prophylaxis-treated infants required hospitalization for RSV. Comparison of the cohort of infants born before initiation of prophylaxis to the cohort born after initiation of prophylaxis (includes prophylaxis-treated and non-prophylaxis-treated infants) revealed a significant reduction in severity of illness and cost. The length of stay in the cohort born before initiation of prophylaxis was reduced 83.8%: 373.6 days per 100 infants at risk vs. 60.5 (P = 0.00055). The length of stay in the pediatric intensive care unit was reduced 92.7%: 218.2 days per 100 infants at risk vs. 15.9 (P = 0.00029). The duration of intubation was reduced 95.6%: 187.4 days per 100 infants at risk vs. 8.2 (P = 0.00024). The dollars spent for RSV-related care (hospitalizations and prophylaxis) per 100 infants at risk for RSV was reduced 65% in the cohort of infants born after prophylaxis: $670,590 per 100 infants at risk vs. $234,596 (P = 0.00056). This reduction remained significant (64.9%) if the cost of ribavirin (drug and administration fees) was excluded from the cost of hospitalization.

CONCLUSIONS

These data reveal that RSV prophylaxis significantly reduced the incidence of RSV hospitalizations and severity of illness as well as the cost of RSV-related care among these infants.

Immunoglobulin for preventing respiratory syncytial virus infection

BACKGROUND

Respiratory Syncytial virus, the most important cause of lower respiratory tract infections in infants and young children in industrialized countries, is associated with increased morbidity in premature infants with or without bronchopulmonary dysplasia as well as those with congenital heart disease. Because of observations that lower rates of disease occur immediately after birth, presumably due to vertical transmission of maternal antibody, and animal studies where protection from pneumonia was observed through administration of immune globulin, the efficacy of passive prophylaxis in premature infants has been studied.

OBJECTIVES

This meta-analysis was performed to assess the effects of polyclonal respiratory syncytial virus hyperimmune globulin or monoclonal antibody in preventing RSV hospitalization, receipt of intensive care, mechanical ventilation, and mortality in those with underlying prematurity, bronchopulmonary dysplasia, or congenital heart disease.

SEARCH STRATEGY

We searched the Cochrane Acute Respiratory Infections trials register and MEDLINE in March, 1999. In addition, abstracts on these topics were sought from the Pediatric Academies Meetings and the Intersciences Conference on Antimicrobial Agents and Chemotherapy for the years 1994 to 1997, inclusive.

SELECTION CRITERIA

Randomized, controlled trials of prevention of RSV using immune globulin, respiratory syncytial virus immune globulin, or monoclonal RSV antibody in children with prematurity, bronchopulmonary dysplasia or congenital heart disease.

DATA COLLECTION AND ANALYSIS

Two authors independently abstracted data and assessed study quality. Only incidences could be pooled because data for durations was summarized in a manner that did not allow combining results across the studies.

MAIN RESULTS

Four studies with a total of 2598 subjects were included in the main analysis. All were randomized controlled trials. Two trials were not blinded. Three studies examined RSV hyperimmune globulin and one examined monoclonal RSV antibody. A study of a different monoclonal RSV antibody could not be included because it has not been presented or published. The pooled Peto Odds Ratios favoring prophylaxis were 0.48 (95% CI 0.37, 0.64), 0.47 (0.29, 0. 77), and 0.99 (0.48, 2.07) for incidence of hospitalization, incidence of ICU admission, and incidence of mechanical ventilation, respectively. The numbers needed to prevent one hospitalization and one ICU admission are 17 and 50 respectively.

REVIEWER'S CONCLUSIONS

RSVIG is effective in preventing RSV hospitalizations and admission to the intensive care unit, but not in preventing mechanical ventilation. There was a non-significant trend towards a higher mortality in children given RSVIG.

Cost-effectiveness of respiratory syncytial virus prophylaxis among preterm infants

OBJECTIVES

To evaluate the costs and benefits of two new agents, respiratory syncytial virus immune globulin (RSVIG) and palivizumab, to prevent respiratory syncytial virus (RSV) infection among premature infants discharged from the neonatal intensive care unit (NICU) before the start of the RSV season. Method. Decision analysis was used to compare the projected societal cost-effectiveness of three strategies-RSVIG, palivizumab, and no prophylaxis-among a hypothetical cohort of premature infants. Probabilities and costs of hospitalization were derived from a cohort of 1721 premature infants discharged from six Kaiser Permanente-Northern California NICUs. Efficacies of prophylaxis were based on published trials. Costs of prophylaxis were derived from published sources. Mortality among infants hospitalized for RSV was assumed to be 1.2%. Future benefits were discounted at 3%.

RESULTS

Palivizumab was both more effective and less costly than RSVIG. Cost-effectiveness varied widely by subgroup. Palivizumab appeared most cost-effective for infants whose gestational age was </=32 weeks, who required >/=28 days of oxygen in the NICU, and who were discharged from the NICU from September through November. In this subgroup, palivizumab was predicted to cost $12,000 per hospitalization averted (after taking into account savings from prevention of RSV admissions) or $33,000 per life-year saved, and the number needed to treat to avoid one hospitalization was estimated at 7.4. However, for all other subgroups, ratios ranged from $39,000 to $420,000 per hospitalization averted or $110,000 to $1,200,000 per life-year saved, and the number needed to treat extended from 15 to 152. The results were sensitive to varying assumptions about the cost and efficacy of prophylaxis, as well as the probability of hospitalization, but were less sensitive to the cost of hospitalization.

CONCLUSION

In our model, the cost of prophylaxis against RSV for most subgroups of preterm infants was high relative to the benefits realized. Lower costs might permit the benefits of prophylaxis to be extended to additional groups of preterm infants.

Recent developments in the biology of respiratory syncytial virus: are vaccines and new treatments just round the corner?

Respiratory syncytial virus (RSV) is the major cause of infantile bronchiolitis, and is an important pathogen in the elderly and in the developing world. The production of full length cDNA clones now allows precise genetic engineering of RSV, while knowledge of the immunopathogenesis of augmented disease gives hope that effective vaccines will soon be developed.

Impact of palivizumab on expected costs of respiratory syncytial virus infection in preterm infants: potential for savings

In its clinical assessment of the respiratory syncytial virus (RSV)-specific monoclonal antibody palivizumab, the IMpact-RSV Study Group demonstrated a reduction in hospitalizations for RSV-related lower respiratory tract infection in infants who received prophylaxis compared with infants who did not receive prophylaxis. An assessment of the RSV-related expenses for managing both groups of infants is needed to provide insight into the value of prophylaxis. The present study was conducted to identify and compare RSV-related health care expenditures incurred by infants who did not receive prophylaxis throughout one RSV season and after. Using a decision-analytic model populated with data from the contemporary medical literature, a pharmacoeconomic study was conducted from the perspective of the payer. Probabilities for RSV-related hospitalizations of infants who did and did not receive prophylaxis were abstracted from several published studies. Components of inpatient and outpatient care were identified through examination of hospital records, reviews of the published literature, and consultation with expert clinicians. Charges related to prophylaxis and medical management of infection were abstracted from hospital billing records and published data. Appropriate charges were applied to decision-tree branches and multiplied by in-line probabilities for outcomes. Products at terminal nodes were summed to establish total expected charges for both groups of infants. Widespread clinical use of prophylactic palivizumab would result in incremental expenses < or =$3459 per infant or cost savings < or =$39,107 per infant. The variability in value of prophylaxis derives from the rate of RSV-related hospitalizations in the community and the total health care expense of managing infected infants.

Prevention of respiratory syncytial virus infections: indications for the use of palivizumab and update on the use of RSV-IGIV. American Academy of Pediatrics Committee on Infectious Diseases and Committee of Fetus and Newborn

The Food and Drug Administration recently approved the use of palivizumab (pal-vizh-mäb), an intramuscularly administered monoclonal antibody preparation. Recommendations for its use are based on a large, randomized study demonstrating a 55% reduction in the risk of hospitalization attributable to respiratory syncytial virus (RSV) infections in high-risk pediatric patients. Infants and children with chronic lung disease (CLD), formerly designated bronchopulmonary dysplasia, as well as prematurely born infants without CLD experienced a reduced number of hospitalizations while receiving palivizumab compared with a placebo. Both palivizumab and respiratory syncytial virus immune globulin intravenous (RSV-IGIV) are available for protecting high-risk children against serious complications from RSV infections. Palivizumab is preferred for most high-risk children because of ease of administration (intramuscular), lack of interference with measles-mumps-rubella vaccine and varicella vaccine, and lack of complications associated with intravenous administration of human immune globulin products. RSV-IGIV, however, provides additional protection against other respiratory viral illnesses and may be preferred for selected high-risk children including those receiving replacement intravenous immune globulin because of underlying immune deficiency or human immuno-deficiency virus infection. For premature infants about to be discharged from hospitals during the RSV season, physicians could consider administering RSV-IGIV for the first month of prophylaxis. Most of the guidelines from the American Academy of Pediatrics for the selection of infants and children to receive RSV-prophylaxis remain unchanged. Palivizumab has been shown to provide benefit for infants who were 32 to 35 weeks of gestation at birth. RSV-IGIV is contraindicated and palivizumab is not recommended for children with cyanotic congenital heart disease. The number of patients with adverse events judged to be related to palivizumab was similar to that of the placebo group (11% vs 10%, respectively); discontinuation of injections for adverse events related to palivizumab was rare.