Use of palivizumab in children with congenital heart disease

Family and Child Risk Factors for Early-Life RSV Illness

BACKGROUND AND OBJECTIVES

Most infants hospitalized with respiratory syncytial virus (RSV) do not meet common "high-risk" criteria and are otherwise healthy. The objective of this study was to quantify the risks and relative importance of socioeconomic factors for severe, early-life RSV-related illness. We hypothesized several of these factors, particularly those indicating severe social vulnerability, would have statistically significant associations with increased RSV hospitalization rates and may offer impactful targets for population-based RSV prevention strategies, such as prophylaxis programs.

METHODS

We used linked health, laboratory, and sociodemographic administrative data for all children born in Ontario (2012-2018) to identify all RSV-related hospitalizations occurring before the third birthday or end of follow-up (March 31, 2019). We estimated rate ratios and population attributable fractions using a fully adjusted model.

RESULTS

A total of 11 782 RSV-related hospitalizations were identified among 789 484 children. Multiple socioeconomic factors were independently associated with increased RSV-related admissions, including young maternal age, maternal criminal involvement, and maternal history of serious mental health and/or addiction concerns. For example, an estimated 4.1% (95% confidence interval: 2.2 to 5.9) of RSV-related admissions could be prevented by eliminating the increased admissions risks among children whose mothers used welfare-based drug insurance. Notably, 41.6% (95% confidence interval: 39.6 to 43.5) of admissions may be prevented by targeting older siblings (eg, through vaccination).

CONCLUSIONS

Many social factors were independently associated with early-life RSV-related hospitalization. Existing RSV prophylaxis and emerging vaccination programs should consider the importance of both clinical and social risk factors when determining eligibility and promoting compliance.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Palivizumab's real-world effectiveness: a population-based study in Ontario, Canada, 1993-2017

OBJECTIVE

To evaluate the effectiveness of two palivizumab programmes targeting high-risk infants, defined by prematurity, diagnosis of comorbidities and geography, and assess potential disparities by neighbourhood income.

DESIGN

Controlled, interrupted time series.

SETTING

Ontario, Canada.

PATIENTS

We used linked health and demographic administrative databases to identify all children born in hospitals 1 January 1993 through 31 December 2016. Follow-up ended at the earliest of second birthday or 30 June 2017.

INTERVENTION

Palivizumab-eligibility: child was born very preterm and ≤6 months old during respiratory syncytial virus (RSV) season; <24 months old with significant chronic lung or congenital heart disease; or ≤6 months, born preterm or residents of remote regions.

MAIN OUTCOME

Severe RSV-related illness, defined as hospitalisation or death with a diagnosis of bronchiolitis, RSV pneumonia or RSV.

RESULTS

3 million births and 87 000 RSV-related events were identified. Over the study period, rates of severe RSV-related illness declined 65.4% among the highest risk group, eligible infants <6 months (230.6 to 79.8 admissions per 1000 child-years). Relative to changes among ineligible infants <6 months, rates dropped 10.4% (95% CI -18.6% to 39.4%) among eligible infants immediately following introduction of a national palivizumab programme in 1998. Initially, rates were considerably higher among infants from low-income neighbourhoods, but income-specific rates converged over time among eligible infants <6 months; such convergence was not seen among other children.

CONCLUSIONS

Incidence of severe RSV-related illness declined over the study period. While we cannot attribute causality, the timing and magnitude of these declines suggest impact of palivizumab in reducing RSV burden and diminishing social inequities among palivizumab-eligible infants.

Revised recommendations concerning palivizumab prophylaxis for respiratory syncytial virus (RSV)

Respiratory Syncytial Virus infections are one of the leading causes of severe respiratory diseases that require hospitalization and, in some cases, intensive care. Once resolved, there may be respiratory sequelae of varying severity. The lack of effective treatments for bronchiolitis and the lack of vaccines for RSV accentuate the role of prevention in decreasing the impact of this disease. Prevention of bronchiolitis strongly relies on the adoption of environment and the hygienic behavior measures; an additional prophylactic effect may be offered, in selected cases, by Palivizumab, a humanized monoclonal antibody produced by recombinant DNA technology, able to prevent RSV infection by blocking viral replication.After many years the Italian Society of Neonatology, on the basis of the most recent scientific knowledge, has decided to revise recommendations for the use of palivizumab in the prevention of RSV infection.

Preventing hospitalizations for respiratory syncytial virus infection

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

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

OBJECTIVES

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

STUDY DESIGN

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

RESULTS

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

CONCLUSIONS

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

First year of life medication use and hospital admission rates: premature compared with term infants

OBJECTIVE

To compare hospitalization and medication use during the first year of life in preterm-born and term-born infants.

STUDY DESIGN

Data for this retrospective cohort study were obtained from the linked PHARMO-Netherlands Perinatal Registry cohort. From this linked birth cohort, preterm infants (<37 weeks) born between 2004 and 2007 were randomly matched to 4 full-term infants. During follow-up, hospitalization and medication use were assessed. Cox proportional hazard regression models were used to estimate and compare the relative risk (RR) of hospitalization and medication use in preterm and full-term infants. Population-attributable risk percentages were calculated to estimate the proportion of hospitalizations and medication use attributable to preterm birth.

RESULTS

Among the 71,607 singletons born between 2004-2007, 4277 (6%) were born preterm. Of these, 90% were hospitalized at birth, compared with 55% of full-term infants. Preterm infants were twice as likely to be rehospitalized (RR, 2.0; 95% CI, 1.9-2.2), specifically for respiratory-related diseases. Prematurity accounted for 6% of the respiratory disease readmissions. The most frequently used outpatient drugs in the second half year of life were antibacterials for systemic use and drugs for obstructive airway diseases. Preterm infants were 50% more likely to receive a respiratory medication (RR, 1.5; 95% CI, 1.4-1.7).

CONCLUSION

In the first year of life, preterm born infants are up to 2 times more likely than full-term infants to be hospitalized or use medication, especially related to respiratory disease.

The cost effectiveness of palivizumab in congenital heart disease: a review of the current evidence

OBJECTIVE

To review and summarize the literature concerning the cost-effectiveness of palivizumab compared to no prophylaxis in infants and young children with congenital heart disease (CHD).

METHODS

A systematic literature search (MEDLINE to March 2012, limited to English language) identified studies that examined the cost-effectiveness of palivizumab in CHD populations. The quality of each study was assigned a quality score of 1-100 based on the Quality of Health Economic Studies (QHES) instrument.

RESULTS

Ten studies were identified through the search strategy, of which four principally addressed the research question and six additional articles examined CHD in conjunction with other high-risk indications for palivizumab in their economic analyses. QHES for the studies ranged from 58-100, with a median score of 93 (76 for principal articles, 94 for secondary analyses). Cost-utility analyses, which evaluated costs per quality-adjusted life year (QALY), showed favorable results in five analyses (range $10,329-$16,648 per QALY), while the other two suggested no cost-effectiveness ($146,061 and $169,971 per QALY). Of three cost-effectiveness analyses, which assessed costs per hospital admission prevented (HAP), two concluded that the drug was not cost-effective ($16,216/day of hospitalization prevented and $868,296/HAP), while one did not interpret the final result ($43,561/HAP).

LIMITATIONS

Significant variance exists across study characteristics, analytic models utilized, duration of RSV seasons assessed, primary outcome measures evaluated, sensitivity analyses conducted, and other model assumptions. Further, it was difficult to obtain true CHD-based quality scores for the studies that analyzed more than one indication.

CONCLUSIONS

The findings of this review currently remain inconclusive. Although a favorable trend was identified in the cost-utility analyses, additional rigorously conducted studies are necessary to better estimate the cost-effectiveness of palivizumab for CHD infants in clinical practice.

Respiratory hospitalizations and respiratory syncytial virus prophylaxis in special populations

Palivizumab utilization, compliance, and outcomes were examined in infants with preexisting medical diseases within the Canadian Registry Database (CARESS) to aid in developing guidelines for potential "at-risk" infants in the future. Infants who received ≥1 dose of palivizumab during the 2006-2010 respiratory syncytial virus (RSV) seasons at 29 sites were recruited and utilization, compliance, and outcomes related to respiratory infection/illness (RI) events were collected monthly. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for premature infants ≤35 completed weeks gestational age (GA) who met standard approval criteria (group 1) compared to those with medical disorders (group 2) using Cox proportional hazards regression models with adjustment for potential confounding factors. Of 7,339 registry infants, 4,880 were in group 1 and 952 in group 2, which included those with Down syndrome (20.3%), upper airway anomalies (18.7%), pulmonary diseases (13.3%), and cystic fibrosis (12.3%). Group 2 were older at enrollment (10.2 ± 9.2 vs. 3.5 ± 3.1 months, p < 0.0005), had higher GA (35.9 ± 6.0 vs. 31.0 ± 5.4 weeks, p < 0.0005), and were less compliant with treatment intervals (69.4% vs. 72.6%, p = 0.048). A greater proportion of group 2 infants were hospitalized for RI (9.0% vs. 4.2%, p < 0.0005) and RSV (2.4% vs. 1.3%, p = 0.003) (unadjusted). Being in group 2 was associated with an increased risk of RI (HR = 2.0, 95%CI 1.5-2.5, p < 0.0005), but not RSV hospitalization (HR = 1.6, 95% CI 0.9-2.8, p = 0.106). In infants receiving palivizumab, those with underlying medical disorders, though not currently approved for prophylaxis, are at higher risk for RI events compared with preterm infants. However, risk of RSV hospitalizations is similar.

CARESS: the Canadian registry of palivizumab

BACKGROUND

Palivizumab is indicated for respiratory syncytial virus (RSV) prophylaxis in high-risk children. However, relatively little is known about the current use, compliance, and outcomes associated with this medication.

METHODS

A prospective, observational, registry based on 27 sites, with monthly follow-up of infants at high risk for RSV who received at least 1 dose of palivizumab during the 2005-2009 RSV seasons.

RESULTS

A total of 5286 children were enrolled (56.6% male; 71.7% white; average gestational age, 32.1 ± 5.5 weeks). Of them, 3741 patients (70.8%) were prophylaxed for prematurity only, 449 (8.5%) for bronchopulmonary dysplasia/chronic lung disease, 508 (9.6%) for congenital heart disease, and 588 (11.1%) for other reasons. Overall, 19,485 doses were given. On average, infants received 86.0% ± 28.4% of their expected number of injections; 71.2% of infants received their injections in the recommended time periods. Of the 5286 participants enrolled, 308 patients were hospitalized for respiratory tract illness (hospitalization rate, 5.8%). The RSV-hospitalization rate was calculated as 1.38%. Having siblings increased likelihood of hospitalization (66.9% vs. 55.7%, P < 0.005), and was significantly correlated with time to hospitalization in this cohort (P = 0.050).

CONCLUSIONS

The overall RSV-hospitalization rate in our study was within the range found in previous reports (1.3%-5.3%), although it did not mimic the declining rates of the US Palivizumab Outcomes Registry. This could be due to increased testing for RSV when hospitalized and increasing rates of prophylaxis of infants with underlying medical disorders.

Economic evaluation of palivizumab in children with congenital heart disease: a Canadian perspective

BACKGROUND

Respiratory syncytial virus (RSV) is a common cause of bronchiolitis in infants. In children with congenital heart disease (CHD), it is associated with significant morbidity and mortality. Palivizumab is a monoclonal antibody that reduces the number of RSV-associated hospitalizations in children with CHD. We sought to assess cost savings and cost-effectiveness of palivizumab in children < 2 years old with hemodynamically significant CHD in a provincially administered RSV prophylaxis program.

METHODS

A cohort of children who received palivizumab (N = 292) from 2003-2007 was compared to a historical cohort of children (N = 412) from 1998-2003 who met the eligibility criteria for palivizumab prior to initiation of the prophylaxis program. Direct and indirect costs and benefits were determined.

RESULTS

The direct and indirect costs in the historical cohort were $838 per patient season compared to $9130 per patient season in the palivizumab cohort. Risk of admission was reduced by 42%, and days in hospital were reduced by 83%. The incremental cost of the RSV prophylaxis program was $8292 per patient for 1 RSV season. The incremental cost to prevent 1 day of hospitalization was $15,514. The cost of palivizumab accounted for 87.9% of the cost of prophylaxis.

CONCLUSIONS

Palivizumab is clinically effective; however, the cost was exceptionally high relative to the outcomes in this population. Given the financial constraints in a public health care setting, more strict criteria for patient selection or reduced drug costs would improve the cost-effectiveness of RSV prophylaxis.

A decade of respiratory syncytial virus epidemiology and prophylaxis: translating evidence into everyday clinical practice

Respiratory syncytial virus (RSV) is a common infection in infancy, with nearly all children affected by two years of age. Approximately 0.5% to 2.0% of all children are hospitalized with lower respiratory tract disease, of which 50% to 90% have bronchiolitis and 5% to 40% have pneumonia. Morbidity and mortality are highest in children with nosocomial infection and in those with underlying medical illnesses such as cardiac and chronic lung disease. Aboriginal children residing in remote northern regions are specifically considered to be at high risk for hospitalization due to RSV infection. Thorough hand washing and health education are the principal strategies in primary prevention. In the absence of a vaccine, palivizumab prophylaxis is currently the best intervention to reduce the burden of illness and RSV-related hospitalization in high-risk children. Health care professionals should provide palivizumab prophylaxis cost effectively in accordance with recommendations issued by pediatric societies and national advisory bodies. The present article reviews the epidemiology of RSV infection and the short- and long-term impact of disease in high-risk infants and special populations. Prevention strategies and treatment are discussed based on the existing scientific evidence, and future challenges in the management of RSV infection are addressed.

Prevention of respiratory syncytial virus infection

Respiratory syncytial virus (RSV) infection is the leading cause of lower respiratory tract infection in young children, with significant numbers of premature infants and those with other risk factors requiring hospitalization in Canada each year. Palivizumab, an RSV-specific monoclonal antibody, can reduce the hospitalization rate and severity of illness for a small group of high-risk or premature infants during their first RSV season. The present statement reviews the published literature and provides recommendations regarding its use in premature and other at-risk infants, for Canadian physicians.

Incidence and risk factors of hospitalization for bronchiolitis in preterm children: a retrospective longitudinal study in Italy

BACKGROUND

Bronchiolitis is a distressing, potentially life-threatening respiratory condition that affects infants. We evaluated the incidence and risk factors of hospitalization for broncholitis in preterm infants (i.e., a gestational age of <36 weeks) born between 2000 and 2006, and the use and impact of Palivizumab, a monoclonal antibody that in randomized clinical trials has been shown to lessen the severity of RSV-related bronchiolitis.

METHODS

Retrospective cohort study that linked data from four health administrative databases in the Lazio region (a region of central Italy): the birth register, the hospital discharge register, and two ad-hoc databases that record the doses of Palivizumab administered at two local health units.

RESULTS

Among 2407 preterm infants, 137 had at least one hospitalization for bronchiolitis in the first 18 months of life, an overall incidence rate of 4.70 per 100 person-years (95%CI: 3.98-5.56); similar incidence rates were observed by calendar year. A multiple Poisson model showed that the following characteristics were associated with higher incidence: younger age of the infant, the period between October-April, male gender, low Apgar score at birth, low birth weight, and low maternal educational level. At least one dose of Palivizumab was administered to 324 (13.5%) children; a dramatic increase from 2000 (2.8%) to 2006 (19.1%) (p < 0.01) was observed. Other factors independently associated with more frequent Palivizumab use were older maternal age, Italian-born mothers, female gender, low Apgar score, low birth weight, shorter gestational age, a diagnosis of broncho-dysplasia, and the month of birth. It is of note that none of the 34 children with congenital heart disease were prescribed Palivizumab. Performing several multiple Poisson models that also considered Palivizumab use as covariate, although the point estimates were in agreement with previous clinical trial results, we did not find in most of them a significant reduction for immunized children to be hospitalized for bronchiolitis.

CONCLUSION

In Italy the incidence of hospitalization for bronchiolitis, and its associated risk factors, are similar to that found in other countries. Although Palivizumab use is associated with the most important characteristics of severe prematurity, other aspects of its non-use in children with congenital heart disease, the age and the birth country of the mother suggest the need for public health measures that can reduce these health disparities. Finally, the estimated effectiveness of Palivizumab in routine practice, although not significant, confirms the results of previous clinical trials, but its impact on modifying the temporal trend in this population is still negligible.

Optimizing the delivery and use of a new monoclonal antibody in children with congenital heart disease: a successful provincial respiratory syncytial virus prophylaxis program

OBJECTIVES

To describe a program for passive immunization against respiratory syncytial virus infection in infants with hemodynamically significant congenital heart disease (CHD) in accordance with the Canadian Paediatric Society recommendations.

METHODS

A provincial coordinating committee composed of specialists in pediatrics, cardiology, infectious diseases, neonatology and public health collaborated to develop and implement a program to identify children with hemodynamically significant heart disease and offer respiratory syncytial virus prophylaxis. Database records for all children younger than two years of age who were seen by the provincial pediatric cardiology referral service were reviewed. Children with hemodynamically significant heart disease, as determined by a clinical assessment and echocardiography, were considered to be eligible for monthly palivizumab prophylaxis for five winter months. All physicians in the province were notified that approval of the provincial cardiology service was required for prophylaxis to be administered. Immunization rates were compared with projected rates based on the expected population-based immunization rates in infants with CHD in other provinces.

RESULTS

401 children with any cardiac diagnoses were identified, representing 545 potential patient-seasons of prophylaxis over two years in a birth cohort of 20,173 and 19,227 children, in each respective season (13.8 patient-seasons per 1000 births). Of these, 21 children were eligible for palivizumab prophylaxis according to the Canadian Paediatric Society criteria. All eligible children were immunized, and no ineligible children received the immunization. A review of palivizumab use in other provinces revealed highly variable rates of prophylaxis.

CONCLUSIONS

The use of palivizumab for children with CHD can be optimized through a provincial model, in which children requiring prophylaxis are prospectively identified and reviewed by pediatric cardiologists -- and to whom evidence-based guidelines developed by a multidisciplinary team -- are applied. Such a model ensures that all patients requiring prophylaxis receive the appropriate immunization and avoids the immunization of low-risk children with CHD, in whom the benefits of palivizumab have not been proven.

Palivizumab use among children with congenital heart disease in Quebec: Impact of Canadian guidelines on clinical practice

BACKGROUND

Palivizumab has been shown to reduce the risk of hospitalization caused by respiratory syncytial virus in children with congenital heart disease (CHD). Guidelines published in 2003 by the Canadian Paediatric Society (CPS) stated that children younger than 24 months with hemodynamically significant CHD should be considered for up to five monthly doses of palivizumab during the winter season.

OBJECTIVE

To assess the impact of CPS guidelines on the use of palivizumab in children with CHD.

METHODS

Clinical information was reviewed on all patients with CHD who were prescribed palivizumab in 2002-2003 and 2003-2004 and who were followed by one of four paediatric cardiovascular programs in the province of Quebec.

RESULTS

Palivizumab was prescribed to 45 children in 2002-2003 and to 146 children in 2003-2004. The number of children receiving more than five doses increased from 10 of 45 (22%) in 2002-2003 to 57 of 128 (45%) in 2003-2004 (P=0.008). One hundred seventeen of 146 children (80%) receiving palivizumab in 2003-2004 met the CPS guidelines versus 38 of 45 children (84%) in 2002-2003 (ie, before the guidelines were published) (P=0.66). Patients not meeting CPS criteria were older than 24 months at the time of the first dose, had hemodynamically insignificant CHD or had lesions adequately corrected by surgery.

CONCLUSIONS

The number of children with CHD receiving palivizumab prophylaxis increased significantly following the publication of CPS guidelines. The majority of children were eligible for palivizumab according to the current CPS criteria. More patients received more than five doses in 2003-2004 than in 2002-2003.