CARESS: the Canadian registry of palivizumab

Twenty-five years of palivizumab: a global historic review of its impact on the burden of respiratory syncytial virus disease in children

INTRODUCTION

Respiratory syncytial virus (RSV) causes significant morbidity and mortality in young children. For 25 years, palivizumab has been the only effective pharmaceutical RSV preventive.

AREAS COVERED

We summarize the development and a quarter-century of real-world evidence with palivizumab. We highlight its positive impact on the burden of RSV in high-risk children. Based on lessons learnt from its implementation, we suggest strategies for effective and equitable deployment of newer RSV preventives.

EXPERT OPINION

Following failure of the formalin-inactivated RSV vaccine in 1967, RSV intravenous immunoglobulin was approved in 1996 after three decades' research. Subsequently, palivizumab emerged as the most effective and safe RSV preventive, demonstrated by the IMpact trial, and was licensed in 1998 in the United States. Over the last 25 years, the benefits of palivizumab have been firmly established through a wealth of evidence, predominantly from high-income countries (HICs). To achieve a global impact with the newer RSV preventives, evidenced-based universal guidelines must be developed and endorsed by regulatory authorities and relevant scientific societies. Independent economic evaluations should incorporate all RSV-associated healthcare costs, reduction of long-term respiratory sequelae, and standardized outcomes. Most importantly, equity in product availability and implementation, particularly in low- and middle-income countries (LMICs) is essential.

Impact of using the International Risk Scoring Tool on the cost-utility of palivizumab for preventing severe respiratory syncytial virus infection in Canadian moderate-to-late preterm infants

BACKGROUND AND OBJECTIVE

To assess the cost-utility of palivizumab versus no prophylaxis in preventing severe respiratory syncytial virus (RSV) infection in Canadian moderate-to-late preterm (32-35 weeks' gestational age) infants using an: i) International Risk Scoring Tool (IRST); ii) Canadian RST (CRST).

METHODS

A decision tree was developed to assess cost-utility. Infants assessed at moderate- and high-risk of RSV-related hospitalization (RSVH) by the IRST or CRST received palivizumab or no prophylaxis and then progressed to either: i) RSVH; ii) emergency room/outpatient medically attended RSV-infection (MARI); or, iii) were uninfected/non-medically attended. Infants admitted to intensive care could incur mortality (0.43%). Respiratory morbidity was accounted in all uninfected surviving infants for 6 years or 18 years (RSVH/MARI). Palivizumab efficacy (72.2% RSVH reduction) and hospital outcomes were from the Canadian CARESS, PICNIC and RSV-Quebec studies. Palivizumab costs (50mg: CAN$752; 100mg: $1,505) were calculated from Canadian birth statistics combined with a growth algorithm. Healthcare/payer and societal costs (May 2022; 1.5% discounting) were included.

RESULTS

Cost per quality-adjusted life year (QALY) was $29,789 with the IRST (0.79 probability of being <$50,000) and $15,833 with the CRST (0.96 probability). The model was most sensitive to utility scores, long-term sequelae, and palivizumab cost. Vial sharing improved the incremental cost-utility ratio (IRST: $22,319; CRST: $9,231).

CONCLUSIONS

Palivizumab was highly cost-effective (vs no prophylaxis) in Canadian moderate-to-late preterm infants using either the IRST or CRST. The IRST has fewer risk factors than the CRST (3 vs 7, respectively), captures more potential RSVHs (85% vs 54%) and provides another option to guide cost-effective RSV prophylaxis in Canada.

Prophylaxis protects infants with congenital heart disease from severe forms of RSV infection: an Italian observational retrospective study : Palivizumab prophylaxis in children with congenital heart disease

BACKGROUND

In children with congenital heart disease (CHD) respiratory syncytial virus (RSV) infection may have a severe course, with increased risk of morbidity and mortality, requiring hospital admission and intensive care. The aim of the present study was to evaluate the effect of prophylaxis with palivizumab in preventing RSV-associated hospitalization in infants with CHD.

METHODS

We carried out an observational, retrospective study in a paediatric cardiology division at a secondary-care centre in Italy, extracting from the database children with CHD who, from November 2004 to March 2022, matched the criteria for palivizumab prophylaxis, to evaluate the hospitalization rate in CHD patients with and without palivizumab prophylaxis and their RSV-related hospitalization characteristics compared with a group of children without CHD and no other underlying clinical conditions (control group, CG), hospitalized for RSV infection.

RESULTS

One hundred twenty-eight children with CHD were enrolled in the study, mainly (71.9%) with increased pulmonary flow, and received palivizumab prophylaxis. Twenty-seven received hospital care for bronchiolitis. Almost all CHD patients hospitalized for bronchiolitis (26 out of 27) received partial prophylaxis (≤ 3 doses). CHD patients with bronchiolitis stay longer in the hospital than control (14.4 ± 21.7 days vs 6.2 ± 2.3 days) some of which require intensive care (n = 4).

CONCLUSIONS

Our study provides evidence of the efficacy of palivizumab in protecting patients with hemodynamically significant CHD under the age of 2 years from RSV disease and its life-threatening complications. Reducing hospitalisation rate, morbidity, and mortality in this category of patients, passive immune prophylaxis with palivizumab may impact healthcare resource availability and utilisation.

A Comparison of Respiratory Syncytial Viral Prophylaxis in Multiple Births versus Singletons in the Canadian Registry of Palivizumab

OBJECTIVE

The aim of this study is to compare respiratory illness-related hospitalization (RIH) and respiratory syncytial virus (RSV)-related hospitalization (RSVH) in multiple births versus singletons, who received palivizumab during the RSV season and participated in the Canadian registry of palivizumab (CARESS).

STUDY DESIGN

Prospective, observational study of infants aged <2 years recruited across 32 centers over 12 RSV seasons from 2005 to 2017. Demographic data were collected at enrolment and RIH events were recorded monthly.

RESULTS

A total of 25,003 infants were enrolled of whom 6,949 (27.8%) were of multiple birth, and 18,054 (72.2%) were singletons. A significantly larger proportion of the multiple births were premature (80.2%) compared with the singleton group (56.8%). Multiples had a lower gestational age (mean ± standard deviation): 31.2 ± 3.2 versus 33.2 ± 5.5 weeks and birth weight (mean: 1,590 ± 606.8 vs. 2,069.4 ± 1068.5 g; both p < 0.0005). They were younger at enrolment (4.5 ± 5.0 vs. 6.1 ± 6.8 months), and fewer attended daycare (1.9 vs. 4.6%), and experienced exposure to smoking (24.5 vs. 29.9%), but more lived in a crowded household (36.7 vs. 19.4%); all p < 0.0005. Multiples had a longer length of neonatal stay (51.1 ± 65.9 vs. 47.9 ± 67.8 days), and more required respiratory support (65.7 vs. 57.7%), but for shorter duration (22.6 ± 32.9 vs. 24.7 ± 40.6 days); all p < 0.001. RIH and RSVH rates (%) in multiples versus singletons were 4.7; 7.7 and 1.4; and 1.6, respectively. Cox regression showed that multiples had a lower risk of RIH compared with singletons (hazard ratio [HR] = 0.616, 95% confidence interval [CI]: 0.543-0.698, p < 0.0005), but not RSVH (HR: 0.77, 95% CI: 0.57-1.02, p = 0.071).

CONCLUSION

Multiple birth infants, who are known to be at greater risk for severe RSVH compared with singletons, are well protected by palivizumab, provided adherence to the monthly injection scheme is guaranteed.

Full compliance with Respiratory syncytial virus prophylaxis was associated with fewer respiratory-related hospital admissions in preterm children: A cohort study

AIM

Although well documented in randomised trials, the efficacy of prophylaxis against respiratory syncytial virus (RSV) in real-word conditions is less studied. The objective was to assess the impact of partial versus full RSV prophylaxis for acute respiratory infections (ARIs) and ARI-related hospital admissions in preterm children.

METHODS

This study included children born preterm in 2011 in France who were eligible for RSV prophylaxis and received at least one palivizumab dose from October 2011 to March 2012. Full prophylaxis was defined as receiving at least one palivizumab dose for each month of RSV exposure in the community. Children with full and partial prophylaxis were matched, and odds of ARIs and ARI-related hospital admission were compared by logistic regression.

RESULTS

Full prophylaxis concerned 861/1083 (80%) children. As compared with full prophylaxis, partial prophylaxis was not associated with ARI occurrence (odds ratio OR 1.3, 95% confidence interval CI 0.9-1.9) but was significantly associated with ARI-related hospital admission during the RSV epidemic (OR 1.9, 95% CI 1.2-2.9).

CONCLUSION

During the 2011-2012 RSV epidemic, hospital admission rates were higher for preterm children with partial than full RSV prophylaxis. Improving compliance could help alleviate the burden of RSV on healthcare systems.

Palivizumab Prophylaxis for infants 29 to 32 weeks gestation at birth: A 10-year audit from Vancouver Island using BC Guidelines

Background

After initially recommending palivizumab (PVZ), a monoclonal antibody against respiratory syncytial virus (RSV) for all infants 29 to 32 weeks at birth if <6 months age at season start, the American Academy of Pediatrics (AAP) and Canadian Paediatric Society (CPS) guidelines were revised. British Columbia was the only jurisdiction in North America to restrict eligibility for this group to those with additional risk factors, long before the change in national recommendations.

Objectives

To determine the risk for first season RSV admission for 29 to 32-week gestational age (GA) infants admitted to Victoria Neonatal Intensive Care Unit (NICU) that either received or were denied PVZ prophylaxis.

Methods

Descriptive cohort study of infants eligible for prophylaxis according to earlier CPS guidelines. Instead, BC guidelines for prophylaxis were applied and data for Vancouver Island infants were collected over 10 consecutive RSV seasons.

Results

We followed 423 infants. Three hundred and thirty-six (79%) did not receive prophylaxis, of which 10 (3.0%; 95% confidence interval [CI] 1.4% to 5.4%) had an RSV hospitalization before the end of April during their first RSV season versus 3 admissions from 87 (3.5%; 95% CI 0.7% to 10%) infants who received prophylaxis.

Conclusions

Our risk factor approach to RSV prophylaxis for infants born at 29 to 32 weeks GA resulted in a low (average incidence=3.1%) rate of RSV hospitalization. Our approach would offer considerable cost savings to RSV prophylaxis programs that continue to offer routine prophylaxis beyond 28/29 weeks GA at birth.

Respiratory Syncytial Virus Immunoprophylaxis with Palivizumab: 12-Year Observational Study of Usage and Outcomes in Canada

OBJECTIVE

This study aimed to evaluate palivizumab (PVZ) use, trends in indications, and outcomes of respiratory illness hospitalizations (RIH) and respiratory syncytial virus hospitalizations (RSVH).

STUDY DESIGN

It involves a large, Canadian prospective (2005-2017) observational multicenter study of children at high risk for RSV infection.

RESULTS

A total of 25,003 infants (56.3% male) were enrolled at 32 sites; 109,579 PVZ injections were administered. Indications included: prematurity (63.3%); "miscellaneous" (17.8%); hemodynamically significant congenital heart disease (10.5%); bronchopulmonary dysplasia/chronic lung disease (8.4%). The "miscellaneous" group increased over time (4.4% in 2005-2006 to 22.5% in 2016-2017) and included: trisomy 21, airway anomalies, pulmonary disorders, cystic fibrosis, neurological impairments, immunocompromised, cardiac aged >2 years, multiple conditions, and a residual "unclassified" group. Adherence measured by expected versus actual doses plus correct interdose interval was 64.7%. A total of 2,054 RIH occurred (6.9%); 198 (9.6%) required intubation. Three hundred thirty-seven hospitalized children were RSV-positive (overall RSVH 1.6%). Risk factors for RSVH included having siblings, attending daycare, family history of atopy, smoking exposure, and crowded household. Infants with 5 risk factors were 9.0 times (95% CI or confidence interval 4.4-18.2; p < 0.0005) more likely to have RSVH than infants without risk factors. Three adverse events occurred; none were fatal.

CONCLUSION

Results are relevant to both clinicians and decision-makers. We confirmed the safety of PVZ. Use of PVZ increased steadily for children with miscellaneous conditions and medical complexity. Medical and social factors pose a risk for severe RIH and RSVH with accompanying burden of illness. A vaccine that protects against RSV is urgently required.

KEY POINTS

· Main indications were prematurity (63.3%); "miscellaneous" (17.8%); hemodynamically significant congenital heart disease (10.5%); bronchopulmonary dysplasia/chronic lung disease (8.4%).. · The proportion of children in the "miscellaneous" group, comprised of those with trisomy 21, airway anomalies, pulmonary disorders, cystic fibrosis, neurological impairments, immunocompromised, cardiac aged >2 years, multiple conditions, and a residual "unclassified" group, increased over time (4.4% in 2005-2006 to 22.5% in 2016-2017).. · Respiratory illness-related hospitalization occurred in 2,054 children (6.9%); 198 (9.6%) required intubation. Three hundred thirty-seven hospitalized children were RSV-positive (overall RSVH: 1.6%)..

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.

Challenges in the prevention or treatment of RSV with emerging new agents in children from low- and middle-income countries

INTRODUCTION

Respiratory syncytial virus (RSV) causes approximately 120,000 deaths annually in children <5 years, with 99% of fatalities occurring in low- and middle-income countries (LMICs).

AREAS COVERED

There are numerous RSV interventions in development, including long-acting monoclonal antibodies, vaccines (maternal and child) and treatments which are expected to become available soon. We reviewed the key challenges and issues that need to be addressed to maximize the impact of these interventions in LMICs. The epidemiology of RSV in LMICs was reviewed (PubMed search to 30 June 2020 inclusive) and the need for more and better-quality data, encompassing hospital admissions, community contacts, and longer-term respiratory morbidity, emphasized. The requirement for an agreed clinical definition of RSV lower respiratory tract infection was proposed. The pros and cons of the new RSV interventions are reviewed from the perspective of LMICs.

EXPERT OPINION

We believe that a vaccine (or combination of vaccines, if practicable) is the only viable solution to the burden of RSV in LMICs. A coordinated program, analogous to that with polio, involving governments, non-governmental organizations, the World Health Organization, the manufacturers and the healthcare community is required to realize the full potential of vaccine(s) and end the devastation of RSV in LMICs.

Cost-analysis of Withdrawing Immunoprophylaxis for Respiratory Syncytial Virus in Infants Born at 33-35 Weeks Gestational Age in Quebec: A Multicenter Retrospective Study

BACKGROUND

In 2015, the Quebec Ministry of Health limited palivizumab prophylaxis for respiratory syncytial virus (RSV) in premature infants to those born at <33 weeks gestational age (wGA), unless other indications were present. We compared RSV-related costs for 2 seasons before the change (2013-2014, 2014-2015) and 2 seasons after (2015-2016, 2016-2017) in premature infants 33-35 wGA.

METHODS

Using payer and societal perspectives, costs associated with hospitalizations for RSV and lower respiratory tract infection (LRTI) in infants born at 33-35 wGA were estimated. Inputs were from a 2013-2017 retrospective cohort study in 25 Quebec hospitals of RSV/LRTI hospitalizations among infants <6 months old at the start of, or born during, the RSV season. Resource utilization data (hospital stay, procedures, visits, transportation, out-of-pocket expenses and work productivity) were collected from charts and parent interviews allowing estimation of direct and indirect costs. Costs, including palivizumab administration, were derived from provincial sources and adjusted to 2018 Canadian dollars. Costs were modeled for preterm infants hospitalized for RSV/LRTI pre- and postrevision of guidelines and with matched term infants hospitalized for RSV/LRTI during 2015-2017 (comparator).

RESULTS

Average total direct and indirect costs for 33-35 wGA infants were higher postrevision of guidelines ($29,208/patient, 2015-2017; n = 130) compared with prerevision ($16,976/patient, 2013-2015; n = 105). Total costs were higher in preterm infants compared with term infants (n = 234) postrevision of guidelines ($29,208/patient vs. $10,291/patient).

CONCLUSIONS

Immunoprophylaxis for RSV in infants born at 33-35 wGA held a cost advantage for hospitalizations due to RSV/LRTI.

Respiratory Syncytial Virus Prophylaxis in Immunocompromised Children: Outcomes From the Canadian RSV Evaluation Study of Palivizumab Registry Over Twelve Seasons (2005-2017)

BACKGROUND

Immunocompromised children are at increased risk for respiratory syncytial virus (RSV) infection with associated morbidity and mortality. Prophylaxis is usually provided to these children on a case-by-case basis.

METHODS

Immunocompromised children who received ≥1 injection of palivizumab were prospectively enrolled across 32 Canadian sites, between 2005 and 2017, during the RSV season. We assessed respiratory illness hospitalization (RIH) and RSV-related hospitalization (RSVH) hazard ratios (HRs) in immunocompromised children versus infants' prophylaxed for standard indications (SI: prematurity ≤35 weeks' gestation, bronchopulmonary dysplasia, and congenital heart disease) and complex medical disorders (CMD). Data were analyzed using t-tests, χ and Cox proportional hazards adjusted for confounders.

RESULTS

A total of 25,003 infants were recruited; 214 immunocompromised, 4283 CMD, 20,506 SI. On average, children received 4.4 ± 1.3 injections. A total of 16,231 children were perfectly adherent (58.4% immunodeficiency, 68.9% CMD, 64.2% SI; P < 0.0005). A higher proportion of immunocompromised children were aboriginal and exposed to smoking compared with CMD and SI. Immunocompromised children also had a higher median; gestational and enrollment age and birth weight compared with CMD and SI. Immunodeficient children had a higher RIH risk compared with SI (HR = 2.4, 95% confidence interval, 1.3-4.7, P = 0.009) but were similar to CMD (HR = 1.7, 95% confidence interval, 0.9-3.4, P = 0.118). RSVH in prophylaxed, immunocompromised children was similar to CMD (HR < 0.005, P = 0.955) and SI (HR < 0.005, P = 0.953).

CONCLUSIONS

Immunocompromised children who received palivizumab had an increased RIH hazard compared with the SI group. Similar RSVH hazard between the 3 groups suggests that immunocompromised children may benefit from palivizumab during the RSV season.

Respiratory Syncytial Virus Prophylaxis in Neurologic and Muscular Disorders in the Canadian Respiratory Syncytial Virus Evaluation Study of Palivizumab

BACKGROUND

This study aimed to examine the risk of respiratory-related hospitalization in children with neurologic and muscular disorders (NMDs) who received respiratory syncytial virus (RSV) prophylaxis in the Canadian RSV Evaluation Study of Palivizumab.

METHODS

Canadian RSV Evaluation Study of Palivizumab is a prospective registry of children who received ≥1 palivizumab injection among 32 Canadian sites. Demographic data were collected at enrollment, and respiratory events were documented monthly. Cox proportional hazard analyses were conducted to compare respiratory illness-related hospitalization (RIH) and RSV-related hospitalization (RSVH) among children with NMD and those prophylaxed for standard indications (SI) and complex medical disorders.

RESULTS

Group differences were found in enrollment age and weight, birth weight, household crowding, neonatal stay and supplemental oxygen requirement (all P < 0.05). RIH and RSVH incidences were 19.2%, 3.3% (NMD, n = 605); 6.0%, 1.5% (SI, n = 20,335), 9.4%, 1.6% (complex medical disorders, n = 4063), respectively. Children with NMD had a higher risk of RIH (hazard ratio [HR]: 1.90; 95% confidence interval (CI): 1.41-2.56; P < 0.0005) than those with SI. RSVH risk was greater in children with NMD compared with both the SI (HR: 2.26; 95% CI: 1.38-3.72; P = 0.001) and complex medical disorders groups (HR: 2.74; 95% CI: 1.55-4.84; P = 0.001). Children with more severe infantile onset NMD had a higher risk of RIH than those with general hypotonic disorders (HR: 1.69; 95% CI: 1.06-2.68; P = 0.027) but not RSVH.

CONCLUSIONS

Children with NMD who received palivizumab had a higher risk of both RIH and RSVH. Our results imply that all children with NMD, regardless of disease severity, are at risk for respiratory-related illness and RSV infection.

Respiratory syncytial virus prophylaxis in infants with congenital airway anomalies compared to standard indications and complex medical disorders

An observational study was conducted of children < 2 years who received ≥ 1 dose of palivizumab in 32 Canadian institutions from 2005 to 2017. We compared respiratory illness (RIH) and respiratory syncytial virus-related hospitalization (RSVH) hazards in children with a congenital airway anomaly (CAA) versus those prophylaxed for standard indications (SI) and serious medical disorders (SMD). Data were assembled on neonatal course, demographics, palivizumab utilization and adherence, and respiratory illness events, and analyzed using ANOVA, chi-square tests and Cox proportional hazards. Twenty-five thousand three children (1219 CAA, 3538 SMD, and 20,246 SI) were enrolled. Palivizumab adherence was 74.8% overall and similar across groups. For 2054 respiratory-related events, 1724 children were hospitalized. RIH rates were 13.6% (CAA), 9.6% (SMD), and 6.0% (SI). RSVH rates were 2.4% (CAA), 1.6% (SMD), and 1.5% (SI). After adjustment for demographic and neonatal differences, children with a CAA had a significantly increased RIH and RSVH hazard relative to SI (RIH, HR = 1.6, 95% CI 1.2-2.2, p = 0.002; RSVH, HR = 2.1, 95% CI 1.0-4.4, p = 0.037) but similar to SMD (RIH, HR = 1.3, 95% CI 0.9-1.9, p = 0.190; RSVH, HR = 1.7, 95% CI 0.7-4.1, p = 0.277).Conclusion: Children with a CAA experience higher RIH risk. RSVH hazard was similar between CAA and SMD but higher for CAA compared to SI, implying that this population requires surveillance for RSV prophylaxis. What is Known: • Children with congenital airway anomalies (CAA) are at risk for respiratory tract illness and respiratory syncytial virus-related hospitalization (RSVH) with accompanying morbidity and mortality • RSV prophylaxis may be useful in children with a CAA, but is not routinely recommended What is New: • Children with a CAA had a 1.6-2.3 fold greater risk of respiratory-related hospitalization and RSVH compared to those prophylaxed for standard, approved indications and serious medical disorders. • RSVH risk in children aged < 2 years with either upper or lower airway anomalies is similar. Children with a CAA require careful surveillance during the RSV season and prophylaxis may be appropriate.

Respiratory syncytial virus prophylaxis in cystic fibrosis: the Canadian registry of palivizumab data (2005-2016)

Respiratory syncytial virus (RSV) may cause severe illness in cystic fibrosis (CF) children, but recommendations vary on prophylaxis. CARESS is a prospective registry of children who received palivizumab in 32 Canadian sites from 2005 to 2016. Demographic data were collected at enrollment and respiratory illness-related events recorded monthly. We reviewed respiratory illness hospitalization (RIH) and RSV hospitalization (RSVH) in CF children aged < 24 months versus those prophylaxed for standard indications (SI; prematurity, chronic lung disease [CLD] and congenital heart disease [CHD]), and complex medical disorders (CM). Of 23,228 children analyzed, 19,452 (83.8%) were SI, 3349 (14.4%) were CM, and 427 (1.8%) were CF. CF children were more likely to be Caucasian, heavier at birth and enrollment, and less likely to have a sibling or live in crowded conditions. CF children were similar to the other groups in daycare attendance, history of atopy, and exposure to smoking. RIH incidences were 4.3% (premature), 13.8% CLD, 11.5% CHD, 11.7% CM, and 6.8% CF. RSVH incidence in CF children was similar to that in the SI and CM groups: 1.1, 1.5, and 2.0% groups respectively. Cox regression analyses showed that compared to CF children, the HRs for RSVH in SI (HR 2.0 95% CI 0.5-8.3, p = 0.3) and CM (HR 2.4, 95% CI 0.6-9.8, p = 0.2) did not differ. CF children are equally at risk for RSVH relative to those prophylaxed for other indications. Pending robust evidence from prospective trials, palivizumab could perhaps be considered in the interim, for young CF patients born early during the RSV season with evidence of serious lung disease.

Past, Present and Future Approaches to the Prevention and Treatment of Respiratory Syncytial Virus Infection in Children

INTRODUCTION

The REGAL (RSV Evidence - A Geographical Archive of the Literature) series has provided a comprehensive review of the published evidence in the field of respiratory syncytial virus (RSV) in Western countries over the last 20 years. This seventh and final publication covers the past, present and future approaches to the prevention and treatment of RSV infection among infants and children.

METHODS

A systematic review was undertaken of publications between January 1, 1995 and December 31, 2017 across PubMed, Embase and The Cochrane Library. Studies reporting data on the effectiveness and tolerability of prophylactic and therapeutic agents for RSV infection were included. Study quality and strength of evidence (SOE) were graded using recognized criteria. A further nonsystematic search of the published literature and Clinicaltrials.gov on antiviral therapies and RSV vaccines currently in development was also undertaken.

RESULTS

The systematic review identified 1441 studies of which 161 were included. Management of RSV remains centered around prophylaxis with the monoclonal antibody palivizumab, which has proven effective in reducing RSV hospitalization (RSVH) in preterm infants < 36 weeks' gestational age (72% reduction), children with bronchopulmonary dysplasia (65% reduction), and infants with hemodynamically significant congenital heart disease (53% reduction) (high SOE). Palivizumab has also shown to be effective in reducing recurrent wheezing following RSVH (high SOE). Treatment of RSV with ribavirin has conflicting success (moderate SOE). Antibodies with increased potency and extended half-life are currently entering phase 3 trials. There are approximately 15 RSV vaccines in clinical development targeting the infant directly or indirectly via the mother.

CONCLUSION

Palivizumab remains the only product licensed for RSV prophylaxis, and only available for high-risk infants. For the general population, there are several promising vaccines and monoclonal antibodies in various stages of clinical development, with the aim to significantly reduce the global healthcare impact of this common viral infection.

FUNDING

AbbVie.

Palivizumab prophylaxis in infants with cystic fibrosis does not delay first isolation of Pseudomonas aeruginosa or Staphylococcus aureus

Respiratory syncytial virus (RSV) infections may worsen cystic fibrosis (CF) lung disease and favor Pseudomonas aeruginosa (Pa) or Staphylococcus aureus (Sa) acquisition, which is of particular importance in the youngest patients. We aimed to determine the effectiveness of PVZ on microbiological outcomes in young children with CF. We conducted a retrospective case-control study to compare these outcomes in children who systematically received PVZ (PVZ+; n = 40) or not (PVZ-; n = 140). One case was matched with at least three same-gender controls born the same year and month. Median (range) age at first Pa isolation was not statistically different between PVZ- (12.3 [3.8-32.6] months) and PVZ+ (10.4 [1.2-33.0] months; p = 0.953) patients. A similar trend was found for Sa (PVZ+: 6.4 [2.0-59.0] months; PVZ-: 3.8 [0.1-74.1] months; p = 0.191). The proportion of Pa isolations by 3 years of age did not differ between groups (PVZ+ 40% vs. PVZ- 41.4%), but this proportion was higher for Sa in the PVZ+ group (97%) than in the PVZ- group (85%; p = 0.001). Healthcare consumption and growth outcomes did not significantly differ between groups.

CONCLUSION

Systematic PVZ use did not delay key pathogen acquisition in young children with CF. What is known: • Palivizumab is the only available monoclonal antibody against respiratory syncytial virus infection. • Whether or not it is useful in infants with cystic fibrosis remains controversial. What is new: • Palivizumab does not delay key pathogens (Pseudomonas aeruginosa, Staphylococcus aureus) first isolation in young children with cystic fibrosis. • Palivizumab does not reduce healthcare consumption or improve growth during the first 3 years of life of young children with cystic fibrosis.

Comparing First- and Second-year Palivizumab Prophylaxis in Patients With Hemodynamically Significant Congenital Heart Disease in the CARESS Database (2005-2015)

BACKGROUND

Respiratory syncytial virus hospitalization (RSVH) rates in children <2 years of age with hemodynamically significant congenital heart disease (HSCHD) are 2- to 4-fold higher compared with healthy term infants. Pediatric recommendations differ as to whether palivizumab is beneficial beyond 1 year of age. The objective of this study was to determine whether differences exist in respiratory-related illness hospitalization (RIH) and RSVH in HSCHD infants receiving palivizumab during the first year versus second year of life in the Canadian Registry of Palivizumab.

METHODS

The Canadian Registry of Palivizumab is a prospective database of infants who received ≥1 dose of palivizumab in 32 hospitals from 2005 to 2015. Demographic data were collected at enrollment and RIH events recorded monthly. Infants <24 months of age with HSCHD were recruited.

RESULTS

Of 1909 HSCHD infants, 1380 (72.3%) in the first year (mean age, 4.2 months) and 529 (27.7%) in the second year of life (mean age, 17.8 months) received prophylaxis. Baseline demographics for day-care attendance, multiple births, enrollment age and weight differed between the groups (all P < 0.05). Additionally, second year infants had a more complicated neonatal course, with significantly longer length of stay (51.2 vs. 24.9 days) compared with those in the first year. The RIH and RSVH rates in the first year were 11.2% and 2.3% and in the second year were 10.6% and 1.7%. Cox regression analysis showed similar hazard for RIH [hazard ratio, 1.9; 95% confidence interval: 0.7-4.6; P = 0.18] and RSVH [hazard ratio, 2.0; 95% confidence interval: 0.2-16.5; P = 0.52].

CONCLUSIONS

Infants in the first and second year of life had a similar RSVH hazard. These findings suggest that infants in the second year with HSCHD, who remain unstable, are equally at risk for RSVH and merit prophylaxis.

Respiratory Syncytial Virus Infection Rates with Limited Use of Palivizumab for Infants Born at 29 to 31+6/7 Weeks Gestational Age

BACKGROUND

Immunoprophylaxis with palivizumab can reduce respiratory syncytial virus (RSV) infections and hospitalizations. Criteria in British Columbia limit the use of palivizumab to infants born at 29 to 31+6/7 weeks gestational age, which differ from guidelines of the American Academy of Pediatrics (AAP) and the Canadian Paediatric Society (CPS).

OBJECTIVE

To determine whether the limited use of palivizumab affected the frequency of hospital visits by RSV-positive infants (termed "RSV-positive hospital visits") who received approval for palivizumab and those who met the AAP/CPS criteria but did not receive approval for palivizumab.

METHODS

Data sets were generated for the period May 1, 2008, to April 30, 2011, to identify infants with gestational age of 29 to 31+6/7 weeks who were born in or transferred to the Fraser Health authority, RSV-positive results for infants less than 12 months of age who had visited Fraser Health sites and BC Children's Hospital, and palivizumab approvals. Infants were matched across these 3 data sets through their personal health numbers.

RESULTS

The study included 359 infants born at 29 to 31+6/7 weeks, of whom 297 met the AAP/CPS criteria. However, only 46 of these 297 received approval for palivizumab according to the BC criteria. Sixteen (4.5%) of the 359 infants had RSV-positive hospital visits during the RSV season (November through March). Of the 46 infants who received approval for palivizumab, 2 (4.3%) had RSV-positive hospital visits, and of the 251 who met the AAP/CPS criteria but did not receive palivizumab approval, 14 (5.6%) had RSV-positive hospital visits. Of the 359 infants, 6 (1.7%) had RSV-positive results while admitted to the neonatal intensive care unit, and 10 (2.8%) tested positive for RSV during a subsequent hospital visit.

CONCLUSIONS

The frequency of RSV-positive hospital visits did not differ between infants who received and those who did not receive approval for palivizumab in the Fraser Health authority. Limited use of palivizumab for RSV prophylaxis led to reasonable rates of RSV-positive hospital visits in the study population.

Outcomes of Infants Receiving Palivizumab Prophylaxis for Respiratory Syncytial Virus in Canada and Italy: An International, Prospective Cohort Study

BACKGROUND

Respiratory syncytial virus (RSV) infection frequently results in RSV-related hospitalization (RSVH) in young infants. We examined the outcomes of palivizumab recipients within the Canadian Registry (CARESS) and the Torino-Verona Italian Registry over the 2002-2014 RSV seasons.

METHODS

RSVHs were captured during the study seasons. Premature infants who received palivizumab (≤35 completed weeks' gestational age; group1) were compared with infants given palivizumab for underlying disorders regardless of gestational age (group 2). Variables and between-group incidences were analyzed. Risk factors associated with RSVH were assessed by logistic regression.

RESULTS

A total of 14,468 palivizumab-exposed infants were enrolled (group 1, n = 9093; group 2, n = 4856; miscellaneous, n = 519). RSVH was significantly more frequent in group 2 (211/4856, 4.34%) versus group 1 infants (216/9093, 2.37% [relative risk 1.93; 95% confidence interval (CI): 1.60-2.33; P < 0.0001]). Infants with neuromuscular disorders (7.88%), airway anomalies (5.95%), bronchopulmonary dysplasia (4.75%) and hemodynamically significant congenital heart disease (4.10%) had the highest RSVH incidences. After multivariable logistic regression, only neuromuscular disease [odds ratio [OR] 4.29; 95% CI: 2.30-8.00; P < 0.01], airway anomalies (OR 3.23; 95% CI: 1.92-5.43; P < 0.01), Down syndrome (OR 2.25; 95% CI: 1.31-3.89; P < 0.01), hemodynamically significant congenital heart disease (OR 2.24; 95% CI: 1.52-3.31; P < 0.001), prematurity ≤28 completed weeks' gestational age (OR 1.82; 95% CI: 1.29-2.58; P < 0.001) and bronchopulmonary dysplasia (OR 1.81; 95% CI: 1.31-2.50; P < 0.001) significantly predicted RSVH. No significant association was detected with the number of doses administered or the time elapsed after the previous dose.

CONCLUSIONS

RSVH rates are higher in infants given palivizumab for reasons other than prematurity. It is uncertain whether these findings relate to inadequate current palivizumab dosing protocols or to a specific increased RSVH risk inherent in infants with severe underlying comorbidities.

Palivizumab Adherence and Outcomes in Canadian Aboriginal Children

BACKGROUND

Aboriginal infants are at risk for serious respiratory infection.

OBJECTIVE

To determine the hazard rate (HR) for respiratory-related illness (RIH) and respiratory syncytial virus (RSV) specific infection hospitalization (RSVH) in Aboriginal versus non-Aboriginal children receiving palivizumab and the effect of adherence on hospitalization.

METHODS

Palivizumab recipients in the Canadian registry from 2005 to 2014 were included. Adherence was determined by the number of palivizumab doses received during the RSV season and interdose time interval. Adherence proportions between groups were compared by χ test. Cox proportional hazard analysis determined the effect of Aboriginal status and adherence on the risk of RIH and RSVH.

RESULTS

Aboriginal infants comprised 3.6% (701/19,235) of the registry. HR was 1.6 [95% confidence interval (CI): 1.3-2.0, P < 0.001] and 1.2 (95% CI: 0.7-2.2, P = 0.383) for RIH and RSVH. Aboriginal infants were 62.8% and 63.3% adherent with all recommended injections and within stipulated time intervals, respectively, whereas 81.9% (χ = 162.45, df = 1, P < 0.001) and 72.4% (χ = 27.35, df = 1, P = 0.002) of non-Aboriginal infants were correspondingly adherent. Only 39.9% of Aboriginals were perfectly adherent (adherent to total number and injection intervals), compared with 61.7% of non-Aboriginals (χ = 133.89, df = 1, P < 0.001). Even after adjustment for known risk factors, being Aboriginal and nonadherent was associated with higher RIH hazard (HR = 1.4, 95% CI: 1.1-1.8; HR = 1.3, 95% CI: 1.1-1.4, P = 0.004), respectively. Aboriginals nonadherent with interdose intervals had a 2.2-fold increased HR for RSVH (HR = 2.2, 95% CI: 1.2-4.2, P = 0.015).

CONCLUSIONS

Prophylaxed Aboriginal infants have a significantly increased RIH and RSVH hazard than non-Aboriginal infants. Improving adherence especially interdose frequency may further reduce hospitalizations in this vulnerable population.

Consensus conference on the appropriateness of palivizumab prophylaxis in respiratory syncytial virus disease

Respiratory syncytial virus infection represents a clinical burden among young children under 24 months. Palivizumab is the only drug licensed in Italy for the prevention of serious lower respiratory tract disease requiring hospitalization caused by respiratory syncytial virus in children at high risk. However recommendations for palivizumab prophylaxis are heterogeneous. Not all the published documents agree about the clinical indications of palivizumab; this could lead to different clinical practices and concerns about the appropriateness of prophylaxis. These issues and the lack of evidence about palivizumab prophylaxis efficacy in specific medical conditions brought on the idea of a consensus conference on the current recommendations for the management and prevention of bronchiolitis, in order to share useful indications. The goal was to perform a review of the evidence regarding the efficacy and the safety of palivizumab and give recommendations in order to harmonize its use. A structured and validated method to conduct the consensus process was adopted. The consensus conference recommends palivizumab prophylaxis in infants born before 29 weeks and younger than 12 months at the start of the epidemic season. According to evidence from literature and experts' opinion, palivizumab prophylaxis is not recommended in preterm infants of gestational age ≥29 weeks, without co-morbidity (i.e., cardiac, bronchopulmonary diseases). The experts identified some clinical rare conditions for which the decision of prophylaxis should be entrusted to the specialists. The evaluation of the appropriateness of palivizumab prophylaxis in the single patient should be documented by the specialists. Pediatr Pulmonol. 2016;51:1088-1096. © 2016 Wiley Periodicals, Inc.

Retrospective Multicenter Study of Respiratory Syncytial Virus Prophylaxis in Korean Children with Congenital Heart Diseases

BACKGROUND AND OBJECTIVES

We conducted a review of current data on respiratory syncytial virus (RSV) prophylaxis with palivizumab, in Korean children with congenital heart diseases (CHD). In 2009, the Korean guideline for RSV prophylaxis had established up to five shots monthly per RSV season, only for children <1 year of age with hemodynamic significance CHD (HS-CHD).

SUBJECTS AND METHODS

During the RSV seasons in 2009-2015, we performed a retrospective review of data for 466 infants with CHD, examined at six centers in Korea.

RESULTS

Infants received an average of 3.7±1.9 (range, 1-10) injections during the RSV season. Fifty-seven HS-CHD patients (12.2%) were hospitalized with breakthrough RSV bronchiolitis, with a recurrence in three patients, one year after the initial check-up. Among patients with simple CHD, only five (1.1%) patients received one additional dose postoperatively, as per the limitations set by the Korean guideline. Among the 30 deaths (6.4%), five (1.1%) were attributed to RSV infection; three to simple CHD, one to Tetralogy of Fallot, and one to hypertrophic cardiomyopathy (HCM). Of the three HCM patients that exceeded guidelines for RSV prophylaxis, two (66.6%) were hospitalized, and one died of RSV infection (33.3%).

CONCLUSION

In accordance to the Korean guideline, minimal injections of palivizumab were administered to patients having HS-CHD <one year of age during the RSV season; the risk of RSV infection remains significant among children with simple CHD, cardiomyopathy, and children above the age of one year with HS-CHD.

Adherence to Palivizumab for Respiratory Syncytial Virus Prevention in the Canadian Registry of Palivizumab

BACKGROUND

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections in infants. Palivizumab, a means of passive prophylaxis, relies on patient adherence to ensure therapeutic effectiveness. The objective of this study is to evaluate the association between adherence and the incidence of RSV-associated outcomes and to identify demographic factors that may impact adherence.

METHODS

Infants were recruited into the Canadian registry of palivizumab (CARESS) with parental consent. Monthly interviews collected information on palivizumab administration and RSV-associated outcomes. An infant was considered adherent if they received all of their expected injections or ≥5 injections within the appropriate interdose intervals.

RESULTS

Nineteen thousand two hundred thirty-five infants received a total of 83,447 injections from October 2005 to May 2014. Adherence was more likely in infants with higher maternal education and in those with siblings. Adherence was less likely in infants of aboriginal descent, with mothers who smoke and older infants. Adherence was significantly associated [odds ratio (95% confidence interval), P value] with a lower incidence of RSV infection [0.74 (0.60-0.93), 0.01] but not with RSV-associated hospitalization. However, in those hospitalized for RSV, adherence was significantly associated with the incidence of intubation and duration of hospitalization, intensive care stay and respiratory support.

CONCLUSIONS

Adherence may have implications in children with less severe RSV infections and those who are already hospitalized for a RSV infection. Our study also identifies subpopulations that are more likely to be nonadherent to palivizumab therapy. Future studies should aim to validate the relationship among adherence, palivizumab levels and RSV-associated outcomes.

Serious Adverse Events in the Canadian Registry of Children Receiving Palivizumab (CARESS) for Respiratory Syncytial Virus Prevention

OBJECTIVES

To evaluate the safety and tolerability of palivizumab for RSV prophylaxis in high-risk children in everyday practice.

METHODS

High-risk children prophylaxed against RSV infection were recruited into a prospective, observational, Canadian RSV Evaluation Study of Palivizumab (CARESS) registry with active, serious adverse event (SAE) monitoring from 2008 to 2013. SAE reports were systematically collected and assessed for severity and relationship to palivizumab. Data were analyzed by Chi-square or Fisher Exact Tests to examine group differences in proportions.

RESULTS

13025 infants received 57392 injections. Hospitalizations for respiratory-related illness (RIH) were reported in 915 patients, and SAEs other than RIH were reported in 52 patients. Of these, 6 (0.05%) patients had a total of 14 hypersensitivity reactions that were deemed possibly or probably related to palivizumab (incidence: 2.8 per 10,000 patient-months). The SAEs of 42 patients were assessed as not related to palivizumab. SAEs in the remaining 4 patients were not classifiable as their records were incomplete. There were no significant demographic predictors of SAE occurrence.

CONCLUSIONS

Under active surveillance, a small proportion of infants in the CARESS registry experienced SAEs that had a potential relationship with palivizumab and these appeared to be unpredictable in terms of onset. Palivizumab appears to be a safe and well-tolerated antibody for RSV prophylaxis in high-risk children in routine practice.

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.

Safety and Effectiveness of Palivizumab in Children at High Risk of Serious Disease Due to Respiratory Syncytial Virus Infection: A Systematic Review

INTRODUCTION

Lower respiratory tract infection (LRTI) is the leading cause of infant mortality globally in post-neonatal infants (i.e., 28-364 days of age). Respiratory syncytial virus (RSV) is the most commonly identified pathogen for infant LRTI and is the second most important cause of death in post-neonatal infants. Despite 50 years of RSV vaccine research, there is still no approved vaccine. Therefore, passive immunity with the monoclonal antibody palivizumab is the sole regulatory-approved option for the prevention of serious LRTI caused by RSV in pediatric patients at high risk of RSV disease.

METHODS

We conducted a comprehensive systematic literature review of randomized controlled trials (RCTs), open-label non-comparative clinical trials, and prospective observational studies/registries, and summarized the evidence related to the safety, efficacy, and effectiveness of palivizumab.

RESULTS

The efficacy of palivizumab, as measured by the relative reduction in RSV-related hospitalization rate compared with placebo ranged from 39% to 78% (P < 0.05) in the 2 pivotal RCTs. A meta-analysis of the RSV-related hospitalization rate from 5 randomized placebo-controlled trials yielded an overall odds ratio of 0.41 (95% CI, 0.31-0.55) in favor of palivizumab prophylaxis over placebo (P < 0.00001). Low rates of RSV-related hospitalizations were observed in palivizumab recipients consistently over time in more than 42,000 pediatric subjects across 7 RCTs, 4 open-label non-comparative trials, and 8 observational studies/registries conducted in 34 countries. In addition, among palivizumab-prophylaxed subjects with breakthrough RSV LRTI, rates of intensive care unit admission and mechanical ventilation from RSV hospitalization also were low and consistent across studies. With respect to safety, no differences were observed between palivizumab and placebo in the blinded RCTs.

CONCLUSION

Rates of RSV hospitalizations and RSV hospitalization-related endpoints in pediatric subjects who received prophylaxis with palivizumab were low and constant over time and across RCTs, open-label non-comparative trials, and observational studies/registries.

A novel six consecutive monthly doses of palivizumab prophylaxis protocol for the prevention of respiratory syncytial virus infection in high-risk preterm infants in Taiwan

BACKGROUND

Respiratory syncytial virus (RSV) circulates year round in Taiwan. A novel six consecutive monthly doses of palivizumab for RSV prevention protocol has been approved for high risk preterm infants since December 2010. This study aimed to determine the clinical effectiveness and safety of this novel protocol for the prevention of RSV infection.

METHODS

From April 2011 to March 2013, we enrolled infants born at ≤28 weeks gestation and infants born at ≤35 weeks gestation with chronic lung disease (CLD) who received palivizumab prophylaxis as study group and followed up for 12 months. Historic control, those who were born and followed up between July 2000 and June 2008, were retrieved for propensity score matching. Primary endpoint was RSV-related hospitalization, and secondary endpoints included the length of hospital stay and intensive care unit (ICU) care.

RESULTS

We enrolled 127 infants (108 infants born at ≤28 weeks and 19 infants born at 29-35 weeks with CLD). They completed 6-dose palivizumab as scheduled. Among the study group, the RSV-related hospitalizations were 2 (1.6%) within 6 months and 5 (3.9%) within 12 months after discharge. We matched 127 infants in the control group with 127 infants in the study group by propensity score matching. The reduction of RSV-related hospitalization rates were 86% (10.2% vs 1.6%, p = 0.002) within 6 months after discharge and 78% (15.7% vs 3.9%, p = 0.004) within 12 months after discharge. Compared to the control group, the rate of ICU care significantly decreased from 7.1% to 0.8% (p = 0.024) within 6 months after discharge and from 7.9% to 0.8% (p = 0.014) within 12 months after discharge. Adverse events were recorded in 6.4% injections.

CONCLUSIONS

Six monthly intramuscular administration of palivizumab is effective for prevention of RSV hospitalization in regions with no single seasonal peak of RSV infection such as Taiwan.

Respiratory syncytial virus prophylaxis in Down syndrome: a prospective cohort study

BACKGROUND AND OBJECTIVES

Children with Down syndrome (DS) are at significant risk for respiratory syncytial virus (RSV) infection and related hospitalization. We compared hospitalization rates due to respiratory tract infection in children with DS aged <2 years who prospectively received palivizumab during the RSV season with a previously published, similar untreated DS birth cohort.

METHODS

A total of 532 children with DS who prospectively received palivizumab were assembled from the prospective Canadian RSV Evaluation Study of Palivizumab registry between 2005 and 2012. The untreated group included 233 children with DS derived from a nationwide Dutch birth cohort from 2003 to 2005. Events during the RSV seasons were counted. Poisson regression analysis was performed to compare incidence rate ratios (95% confidence intervals [CIs]) between groups while controlling for observation length and known risk factors for severe RSV infection.

RESULTS

In total, 31 (23 untreated, 8 treated) RSV-related hospitalizations were documented. The adjusted risk of RSV-related hospitalizations was higher in untreated subjects than in palivizumab recipients (incidence rate ratio 3.63; 95% CI, 1.52-8.67). The adjusted risk of hospitalization for all respiratory tract infection (147 events; 73 untreated, 74 treated) was similar (incidence rate ratio untreated versus palivizumab 1.11; 95% CI, 0.80-1.55).

CONCLUSIONS

These results suggest that palivizumab is associated with a 3.6-fold reduction in the incidence rate ratio for RSV-related hospitalization in children with DS during the first 2 years of life. A randomized trial is needed to determine the efficacy of RSV immunoprophylaxis in this specific high-risk patient population.

Use of palivizumab in infants and young children with severe respiratory disease: a Delphi study

OBJECTIVE

To achieve a consensus of opinion among an expert group of pediatric pulmonologists regarding the appropriateness of the off-label use of palivizumab for some pediatric patients with severe respiratory diseases.

METHODS

A two-round modified Delphi technique was used. A 43-item self-administered questionnaire grouped into seven clinical scenarios was developed. Level of agreement for each statement was ranked on a 0-9 scale with 0 being total disagreement and 9 total agreement. Consensus was sought through the feedback of information and iteration. The final responses were evaluated for median and interquartile range to determine which questions the group had reached consensus about, either affirmatively or negatively.

RESULTS

Consensus was obtained for 24/43 statements (55.81%), including use of palivizumab for prevention of respiratory syncytial virus (RSV) infection in children with severe respiratory involvement due to neuromuscular disease, congenital or acquired immunodeficiency, storage disease, cystic fibrosis, diseases involving impaired ciliary clearance, patients operated on esophageal atresia and/or tracheoesophageal fistula, diaphragmatic hernia, bronchopulmonary malformations, severe tracheomalacia, lung transplant recipients and patients in the waiting list for lung transplant, patients oxygen-dependent for severe interstitial pulmonary disease and patients with severe pulmonary hypertension. Consensus against the use of palivizumab as prevention of RSV infection was also achieved in almost all the recurrent wheezing/asthma attacks situations.

CONCLUSION

A set of indication for off-label uses of palivizumab in pediatric pulmonology was developed in accordance with the degree of professional consensus on which they were based. The applicability of the present results to clinical practice should be evaluated individually and reviewed periodically in the light of new emerging evidence. Further studies are needed to add evidence to the most frequent and clinically oriented scenarios that have shown higher levels of uncertainty.

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.

Hospitalization for respiratory syncytial virus illness in Down syndrome following prophylaxis with palivizumab

BACKGROUND

Down syndrome (DS) is a risk factor for respiratory syncytial virus (RSV) hospitalization, but little is known about prophylaxis in these children.

METHODS

CARESS is a prospective registry of children who received ≥1 dose of palivizumab during the 2006-2012 RSV seasons across 32 sites in Canada. The objective was to compare respiratory illness hospitalization and RSV hospitalization (RSVH) hazard ratios in DS children aged <2 years who received palivizumab versus children who received prophylaxis for standard indications (SI) and for other medical illnesses (MI).

RESULTS

13,310 children were enrolled; DS (600; 4.5%), SI (11,081; 83.3%) and MI (1629, 12.2%), with DS children increasing over the duration from 0.1% (2006) to 4.5% (2012). Participants were significantly different in mean birth weight, gestational and enrollment age and risk factors. Children in each group received an average of 4.3 ± 1.4 (DS), 4.1 ± 1.6 (SI) and 4.5 ± 1.4 (MI) palivizumab injections per RSV season, with DS, differing significantly from SI [F(2, 13,307) = 43.6, P = 0.01] but not MI [F(2, 13 307) = 43.6, P = 0.07]. Compliance rates were similar across the groups. While a significantly greater proportion of SI children had RIHs compared with DS, [hazard ratio: 0.64 (0.48-0.84); P = 0.001] hazard ratios were similar for DS and MI. RSVH incidence rates were: 1.53%, 1.45% and 2.27% for DS, SI and MI, respectively. Neither group nor compliance affected time to RSVH.

CONCLUSIONS

The proportion of DS children who received palivizumab in CARESS has increased almost 45-fold. RSVH rates were low in DS following prophylaxis and hazards were similar to those found in SI and MI.

Identifying and ensuring optimal care for all children at risk of developing serious respiratory syncytial virus disease: a Canadian nurses' perspective

Globally, respiratory syncytial virus (RSV) infection causes substantial morbidity in infants and young children, particularly those with specific risk factors (e.g., prematurity, chronic lung and congenital heart disease). Supportive measures are the mainstay of care for RSV-related disease. In the absence of medical treatments, RSV prophylaxis (RSVP) with palivizumab is recommended for high-risk patients to help reduce the risk of developing serious disease. Geographic distances, language and cultural barriers, and other factors can impede effective education of caregivers regarding the potential impact of RSV disease and benefits of RSVP compliance. We present our experiences developing successful Canadian RSVP programs, organized through a dedicated coordinator or small group of health care staff. These programs focus on identifying all infants and young children eligible for RSVP, effectively educating health care staff and family caregivers, developing educational tools that consider language and cultural factors, and interdisciplinary collaboration and networking throughout the health care system.

Respiratory-related hospitalizations following prophylaxis in the Canadian registry for palivizumab (2005-2012) compared to other international registries

Respiratory syncytial virus (RSV) infection occurs commonly in infants aged ≤2 years, and severe infection results in hospitalization with accompanying morbidity and mortality. Palivizumab has been available for prophylaxis for the past 15 years. Prospective data on patients who received palivizumab from 2005 to 2012 has been assembled in the Canadian registry (CARESS) to document utilization, compliance, and health outcomes in both hospital and community settings. Long-term data is necessary to evaluate the impact of palivizumab on the incidence of RSV infections, minimize healthcare resources, and identify which infant subpopulations are receiving prophylaxis. A database search was also conducted for similar information from published registries, and hospitalization rates were compared to results from randomized clinical trials (RCTs).Overall hospitalization rates (percent; range) for respiratory-related illnesses and RSV-specific infection in infants who meet standard indications for prophylaxis were 6.6 (3.3-7.7) and 1.55 (0.3-2.06), respectively, in CARESS, which closely aligns with registry data from 4 other countries, despite the former comprising the largest cohort of complex patients internationally. Overall RSV-related hospitalization rates were lower across registries compared to equivalent patients in RCTs. Registry data provides valuable information regarding real-world experience with palivizumab, while facilitating the genesis of new research themes.

A comparative study of respiratory syncytial virus (RSV) prophylaxis in premature infants within the Canadian Registry of Palivizumab (CARESS)

We examined the dosing regimens, compliance, and outcomes of premature infants who received palivizumab within the Canadian Registry of Palivizumab (CARESS). Infants receiving ≥1 dose of palivizumab during the 2006-2011 respiratory syncytial virus (RSV) seasons were recruited across 30 sites. Respiratory illness events were captured monthly. Infants ≤32 completed weeks gestational age (GA) (Group 1) were compared to 33-35 completed weeks GA infants (Group 2) following prophylaxis. In total, 6,654 patients were analyzed (Group 1, n = 5,183; Group 2, n = 1,471). The mean GA was 29.9 ± 2.9 versus 34.2 ± 2.2 weeks for Groups 1 and 2, respectively. Group differences were significant (all p-values <0.05) for the following: proportion of males, Caucasians, siblings, multiple births, maternal smoking, smoking during pregnancy, household smokers, >5 household individuals, birth weight, and enrolment age. Overall, infants received 92.6 % of expected injections. Group 1 received significantly more injections, but a greater proportion of Group 2 received injections within recommended intervals. The hospitalization rates were similar for Groups 1 and 2 for respiratory illness (4.7 % vs. 3.7 %, p = 0.1) and RSV (1.5 % vs. 1.4 %, p = 0.3). Neither the time to first respiratory illness [hazard ratio = 0.9, 95 % confidence interval (CI) 0.7-1.2, p = 0.5] nor to first RSV hospitalization (hazard ratio = 1.3, 95 % CI 0.8-2.2, p = 0.3) were different. Compliance with RSV prophylaxis is high. Despite the higher number of palivizumab doses in infants ≤32 completed weeks GA, the two groups' respiratory illness and RSV-positive hospitalization rates were similar.

A prospective, open-label, non-comparative study of palivizumab prophylaxis in children at high risk of serious respiratory syncytial virus disease in the Russian Federation

BACKGROUND

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections (LRTIs) in children globally. Predisposing conditions for the development of serious RSV disease include preterm infants and those with cardiopulmonary illness, including congenital heart disease (CHD) and bronchopulmonary dysplasia (BPD). No vaccine is currently approved for the prevention of RSV infection. It is recommended that children at high risk be prophylactically administered palivizumab, a monoclonal antibody that has been shown in a number of clinical studies to reduce hospitalization rates due to serious RSV infection. The objective of the current study was to determine the safety and effectiveness of palivizumab in preventing serious RSV disease in high-risk children in the Russian Federation. Children at high risk of serious RSV disease (ie, born at ≤ 35 wk gestational age and ≤ 6 mo of age, and/or aged ≤ 24 mo with BPD or hemodynamically significant CHD) were enrolled. Subjects were to receive 3 to 5 monthly injections of palivizumab 15 mg/kg (depending on the month of the initial injection) over the RSV season. The primary endpoint was RSV-related hospitalizations. Adverse events (AEs) were reported through 100 days following the final injection.

RESULTS

One hundred subjects received ≥ 1 injection of palivizumab; 94 completed their dosing schedule. There were no RSV hospitalizations or deaths. Six of 7 subjects hospitalized for respiratory/cardiac conditions had an RSV test, which was negative in all cases. Three non-serious AEs (acute intermittent rhinitis and rhinitis, 1 subject; atopic dermatitis, 1 subject) were considered possibly related to palivizumab. All other AEs were mild or moderate and considered not related/probably not related to palivizumab.

CONCLUSION

Palivizumab was generally well tolerated and effectively prevented serious RSV infection in a mixed population of high-risk children in the Russian Federation.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01006629.

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.

Respiratory syncytial virus hospitalization trends in infants with chronic lung disease of infancy, 1998-2008

OBJECTIVE

Infants with chronic lung disease of infancy (CLDI) are at high risk for severe respiratory syncytial virus (RSV) illness requiring hospitalization. Palivizumab was first licensed in 1998 for the prevention of RSV disease in high-risk infants, including those with CLDI. We performed a retrospective cohort study of all hospitalized children with CLDI aged <2 years between 1998 and 2008 in the USA to determine trends in rates of hospitalizations due to RSV (RSVH) since the launch of palivizumab.

MATERIALS AND METHODS

Data from the United States National Hospital Discharge Survey, a multistage systematic survey sample of US hospitals, were assembled. We defined RSVH using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes of 079.6 (RSV), 466.11 (acute bronchiolitis due to RSV), and 480.1 (pneumonia due to RSV). Quarterly rates of RSVH were assessed for children with CLDI (ICD-9-CM code 770.7) and calculated between 1998 and 2008. Because RSV may be miscoded, the analysis was repeated after expanding the definition of RSVH to include all acute bronchitis and acute bronchiolitis (ABH) (ICD-9-CM = 466). Trends were described using linear regression with seasonal indicators included in the model.

RESULTS

On average, about 966 RSVH (range 98-1373 RSVH) per year were found for children <2 years with CLDI in the USA between 1998 and 2008. Over the 11-year period, the predicted rate of RSVH statistically significantly decreased by 48% (from 93.78 to 49.06 RSVH per 1 million children) (P = 0.013). Addition of ABH resulted in a nonstatisically significant decrease of 32% over the 10-year period (P = 0.102).

CONCLUSION

These results suggest that there has been a decrease in the rate of RSVH in infants with CLDI between 1998 and 2008. The reasons for this decrease may include improved neonatal intensive care unit and outpatient management of CLDI, and possibly increased use of palivizumab in this high-risk population.

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.