Respiratory hospitalizations and respiratory syncytial virus prophylaxis in special populations

Effectiveness and Safety of Palivizumab for the Prevention of Serious Lower Respiratory Tract Infection Caused by Respiratory Syncytial Virus: A Systematic Review

OBJECTIVE

Palivizumab is a humanized monoclonal antibody approved for the prevention of serious lower respiratory tract infection (LRTI) caused by respiratory syncytial virus (RSV) in infants and young children at high risk of RSV disease. This systematic review summarized evidence on the effectiveness and safety of palivizumab when used in approved populations.

STUDY DESIGN

A systematic review of Phase III trials and observational studies was conducted according to the population, intervention, comparator, outcome, timing, setting (PICOTS) approach (PROSPERO, CRD42021281380). Target populations consisted of infants with a history of premature birth (≤35-week gestational age) and children aged <2 years with bronchopulmonary dysplasia (BPD) or with hemodynamically significant congenital heart disease (hs-CHD). Outcomes of interest included RSV-related hospitalization, admission to intensive care unit (ICU), requirement for mechanical ventilation, treatment-related adverse events (AEs), and RSV-related deaths. Information sources were literature search (Ovid MEDLINE and Embase), pragmatic searches, and snowballing (covering the period up to 07 September 2021).

RESULTS

A total of 60 sources were included (5 Phase III trials and 55 observational studies). RSV-related hospitalization rates following palivizumab prophylaxis in Phase III trials were 1.8% in premature infants and 7.9% in children with BPD, which were significantly lower than rates in placebo arms. In the real-world setting, similar hospitalization rates were found (0.7-4.0% in premature infants [16 studies] and 0-5.5% in patients with BPD [10 studies]) with ICU admission reported in 0 to 33.3% of patients hospitalized for RSV. In Phase III trials, RSV-related mortality rates were 0.2 and 0.3%, while AEs occurred in 11% of premature and/or BPD patients and 7.2% of hs-CHD patients, consisting mainly of injection site reaction, fever, and diarrhea. Similar results were found in observational studies.

CONCLUSION

This systematic review supports the effectiveness and safety of palivizumab in the indicated populations.

KEY POINTS

· Systematic review supports the positive benefit-risk profile of palivizumab in the indicated populations.. · Real-world safety and effectiveness of palivizumab are consistent with Phase III trials results.. · Palivizumab reduces RSV-related hospitalizations, ICU admissions, and need for mechanical ventilation..

Review of the Safety, Efficacy and Tolerability of Palivizumab in the Prevention of Severe Respiratory Syncytial Virus (RSV) Disease

Respiratory Syncytial Virus (RSV) is a major global cause of childhood morbidity and mortality. Palivizumab, a monoclonal antibody that provides passive immunity against RSV, is currently licensed for prophylactic use in specific "high-risk" populations, including congenital heart disease, bronchopulmonary dysplasia and prematurity. Available research suggests palivizumab use in these high-risk populations can lead to a reduction in RSV-related hospitalization. However, palivizumab has not been demonstrated to reduce mortality, adverse events or length of hospital stay related to RSV. In this article, we review the management of RSV, indications for palivizumab prophylaxis, the safety, cost-effectiveness and efficacy of this preventative medication, and emerging therapeutics that could revolutionize future prevention of this significant pathogen.

Respiratory syncytial virus bronchiolitis in congenital diaphragmatic hernia: A systematic review of prevalence rates and palivizumab prophylaxis

BACKGROUND

The seasonality of respiratory syncytial virus (RSV) epidemics have been disrupted during the COVID-19 pandemic, possibly because of lockdowns and social restrictions reducing viral transmission. Given uncertainties around the severity of upcoming RSV bronchiolitis epidemics, debate exists whether palivizumab (RSV prophylaxis) should be administered to infants with Congenital Diaphragmatic Hernia (CDH), who may be vulnerable due to lung hypoplasia and pulmonary hypertension.

AIM

To evaluate (1) if CDH infants have higher risk of admission with RSV bronchiolitis than infants in the general population; (2) if palivizumab prophylaxis may reduce this risk.

METHODS

We included all eligible studies examining the risk(s) of RSV-positive bronchiolitis requiring hospital admission in (1) CDH infants without palivizumab prophylaxis versus infants in the general population and (2) CDH infants with prophylaxis versus CDH infants without prophylaxis. The primary outcome evaluated was the risk of admission with RSV bronchiolitis. Data are reported descriptively and meta-analysed when appropriate.

RESULTS

Three eligible retrospective cohort studies were identified: one study found CDH to be an independent risk factor for RSV hospitalisation (odds ratio, 3.30; 95% confidence interval [CI], 2.01-4.4); two studies compared RSV hospitalisation rates in CDH patients who had palivizumab versus those that did not. The pooled risk ratio was 1.11 (95% CI, 0.29-4.23; p = .88). Overall, the quality of evidence was considered poor and one study was industry funded.

CONCLUSION

Whether CDH infants are at particular risk of severe bronchiolitis remains unclear. There is no evidence from this current systematic review that CDH infants should routinely receive palivizumab vaccination prophylaxis.

Pulmonary complications in children with Down syndrome: A scoping review

CONTEXT

Down syndrome (DS) is a prevalent chromosomal disorder associated with a wide range of congenital anomalies and other health problems.

OBJECTIVES

To give a scoping overview of encountered lower airway problems (both infectious and non-infectious) in DS children.

DATA SOURCES

We systematically searched the MEDLINE and PubMed databases for relevant publications.

STUDY SELECTION

Studies were eligible if they were original studies about pediatric airway problems in DS and were evaluated by the PRISMA guidelines.

DATA EXTRACTION

Data concerning patient characteristics, study methods and outcomes were critically reviewed.

RESULTS

Sixty papers were included. These were reviewed and summarized by topic, i.e. airway anomalies, dysphagia and aspiration, lower respiratory tract infections (and bronchiolitis in particular), pulmonary hypertension and other. Respiratory problems are proven to be a frequent and a major health burden in DS children. Airway anomalies (both single and multiple) are more prevalent and require a specific approach. A large proportion of DS children have (often silent) aspiration, resulting in protracted and difficult-to-treat symptoms. Respiratory tract infections are usually more severe and associated with an increased need for (prolonged) hospitalization. Pulmonary hypertension, wheeze and some other rare conditions are more commonly encountered in DS.

LIMITATIONS

Large number of studies and high levels of study heterogeneity.

CONCLUSIONS

Several lower airway problems are more frequent and more complex in children with DS. These findings emphasize the need for a multidisciplinary approach by an experienced team allowing for a prompt diagnosis, proper management and improved long term outcome.

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%)..

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.

Pharmacological targets and emerging treatments for respiratory syncytial virus bronchiolitis

RSV infection of the lower respiratory tract in infants is the leading cause of pediatric hospitalizations and second to malaria in causing infant deaths worldwide. RSV also causes substantial morbidity in immunocompromised and elderly populations. The only available therapeutic is a prophylactic drug called Palivizumab that is a humanized monoclonal antibody, given to high-risk infants. However, this intervention is expensive and has a limited impact on annual hospitalization rates caused by RSV. No vaccine is available, nor are efficacious antivirals to treat an active infection, and there is still no consensus on how infants with bronchiolitis should be treated during hospital admission. In this comprehensive review, we briefly outline the function of the RSV proteins and their suitability as therapeutic targets. We then discuss the most promising drug candidates, their inhibitory mechanisms, and whether they are in the process of clinical trials. We also briefly discuss the reasons for some of the failures in RSV therapeutics and vaccines. In summary, we provide insight into current antiviral development and the considerations toward producing licensed antivirals and therapeutics.

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 hospitalization and incurred morbidities the season after prophylaxis

OBJECTIVES

The primary objective of this study was to determine the incidence and incurred morbidities of Respiratory syncytial virus (RSV)-related hospitalization (RSVH), the season following completion of prophylaxis.

METHODS

A retrospective study was conducted of all infants enrolled in a prophylaxis clinic in one institution during the 2009 to 2014 RSV seasons. RSV infection was identified by Diseases codes and confirmed by RSV-positivity. Data were classified into five groups based on indications for prophylaxis. The incidence of RSVH was calculated. For each subgroup, differences in characteristics between children with and without RSVH were analyzed by independent t test or chi-square test.

RESULTS

During five RSV seasons, 827 infants were enrolled. RSVH incidence the season following prophylaxis was 2.1% (n=17/827). Children with chronic lung disease (CLD) had the highest RSVH incidence (7.7%; n=4/52) followed by preterms 33 to 35 weeks gestation (2.5%; n=4/162), those with complex medical disorders (2.2%; n=3/135), those with congenital heart disease (1.5%; n=1/66) and preterms less than or equal to 32 weeks gestation (1.2%; n=5/412). There was no statistically significant association between indications for prophylaxis and RSVH (Fisher exact test, P=0.060). The odds of RSVH were 4.9 times greater (odds ratio [OR]=4.9; 95% CI: 1.53, 15.55; P=0.007) in CLD compared to those without CLD. The median length of RSVH stay was 4 days; 58.8% (n=10/17) required oxygen (median 1 day); 29.4% (n=5/17) required intensive care.

CONCLUSIONS

Infants with CLD are at highest risk for RSVH in the season postprophylaxis and may merit palivizumab for more than two seasons dependent on disease severity. However, larger prospective studies are necessary to confirm the findings before embarking on a strategy of providing prophylaxis for a third RSV season.

Respiratory syncytial virus (RSV) infection in children with medical complexity

Children with medical complexity (CMC) are vulnerable to respiratory illness hospitalization (RIH) and respiratory syncytial virus (RSV)-related hospitalization (RSVH) due to multisystem disorders and compromised airways. It is unknown whether RSV prophylaxis is effective, or if RSVH is associated with significant morbidities in CMC. The study objectives were to (1) determine the incidence of RSV-related infection in prophylaxed CMC during the first 3 years of life and (2) assess the burden of illness following RSVH. A single tertiary center, retrospective study, was conducted of CMC who received palivizumab during the 2012-2016 RSV seasons. Fifty-four subjects were enrolled; most received one (38.9%, n = 21) or two (57.4%, n = 31) seasons of prophylaxis (mean = 4.2 [SD = 1.24], palivizumab doses per season). The cohort comprised children with multiple medical conditions (n = 22, 40.8%), tracheostomy (n = 18, 33.3%), and invasive (n = 10, 18.5%) or non-invasive (n = 4, 7.4%) ventilation. Of the CMC, 24 were hospitalized 47 times for a viral-related respiratory illness. RSV incidence in the first 3 years of life was 7.4%. Viral-related RIH and RSVH rates were 44.4% (n = 24/54) and 1.9% (n = 1/54), respectively. Of the four RSV-positive children, one was ventilated for 9 days, two acquired nosocomial RSV that was managed on the ward, and one was discharged home under close complex care supervision. All four RSV-positive cases required additional oxygen during their illness. CMC experience a high viral-related RIH rate and palivizumab likely minimizes RSV-related events and associated morbidities. The efficacy of palivizumab in CMC, especially in those ≤ 3 years, should be prospectively evaluated.

Palivizumab use in infants with Down syndrome-report from the German Synagis™ Registry 2009-2016

Infants with Down syndrome (DS) face an increased risk of respiratory tract infections. Recent studies describe DS as independent risk factor for a complicated clinical course in infants with respiratory syncytial virus (RSV) infection. The prospective observational German Synagis™ Registry comprises data from 249 children below 25 months of age with DS and palivizumab prophylaxis 2009-2016 (1191 administrations; mean 4.8 per patient and season). The median gestational age and the birth weight in patients without and with DS were 31 versus 37 weeks (P < 0.001) and 1590 versus 2750 g, respectively (P < 0.001). Patients with DS significantly more often had congenital heart disease (CHD), siblings in kindergarten or school, treatment with oxygen at home, immunodeficiency, and neuromuscular impairment. The RSV-related hospitalization rate in patients with DS was 1.20%; the hospitalization rate in patients without DS was 0.71%.

CONCLUSION

Data from 249 children with DS receiving palivizumab prophylaxis in seven consecutive RSV seasons (2009-2016) in Germany reveal important differences between patients with and without DS concerning the main indication for palivizumab use and additional risk factors. Bearing in mind the limitations of an uncontrolled postmarketing observational study, the results confirm the field effectiveness of palivizumab prophylaxis in this special population. What is Known: • Recent studies describe the Down syndrome as independent risk factor for a complicated clinical course in infants with RSV infection. What is New: • Compared with other infants receiving palivizumab prophylaxis, patients with Down syndrome significantly more often had congenital heart disease, siblings in kindergarten or school, treatment with oxygen at home, immunodeficiency, and neuromuscular impairment. • In infants with palivizumab prophylaxis breakthrough, RSV-related hospitalization rates were not significantly higher in those with Down syndrome.

Respiratory syncytial virus associated hospitalizations in children with congenital diaphragmatic hernia

BACKGROUND

To evaluate the risk of RSV infection in infants and children with congenital diaphragmatic hernia (CDH) over two consecutive RSV seasons.

METHODS

Retrospective, single-center cohort study from southern Austria including infants with CDH born between 1993 and 2012. Infants were retrieved by searching via ICD-10 codes Q79.0 and Q79.1 and by using a local electronic database. Children were followed over 2 years of life including at least two consecutive RSV seasons (November to April). We also defined a group of hypothetical RSV infections with the following criteria: 70% of the admissions due to a respiratory infection (diagnosis of bronchiolitis and/or LRI score ≥3) during the RSV seasons over the first 2 years of life, when no test for RSV was performed.

RESULTS

Twenty-nine of 45 infants with CDH comprised the study population (6 were lost to follow-up and 10 died) of whom 9 (31%) exhibited 17 hospitalizations due to respiratory illness. Two hospitalized infants (6.9% of the study population) tested RSV positive, one during the first and the other during the second RSV season. Nine of 29 infants (31%) had documentation of palivizumab prophylaxis, none (0%) had proven RSV hospitalization compared to 1 of 20 (5%) without prophylaxis during the first RSV season (p = 0.256). Including the hypothetical cases, we calculated 0 of 9 (0%) in the palivizumab group and 4 of 20 (20%) in the group without prophylaxis (p = 0.079).

CONCLUSIONS

We found a moderate rate of proven RSV hospitalizations in infants with CDH, and palivizumab prophylaxis led to a non-significant reduction of proven and hypothesized RSV hospitalizations.

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.

Product review on the monoclonal antibody palivizumab for prevention of respiratory syncytial virus infection

Respiratory syncytial virus (RSV) accounts for about 20% of all respiratory infections in children below the age of 5 y. It is associated with up to 63% of all acute respiratory infections and up to 81% of all viral lower respiratory tract infections causing hospitalization in infants and young children. RSV leads to seasonal epidemics between November and April in the northern hemisphere. Most severe infections (RSV accounts for 50 to 80% of all cause bronchiolitis) affect infants younger than 6 months of age and high-risk infants including those born preterm with or without bronchopulmonary dysplasia and those with hemodynamically significant congenital heart disease up to an age of 24 months. Palivizumab, a highly potent RSV-neutralizing monoclonal antibody (Mab), has been licensed in 1998 for prophylactic use to prevent RSV associated hospitalizations in high-risk infants. This Mab is given by monthly intramuscular injection at a dose of 15 mg/kg over the RSV season (up to 5 times). Palivizumab proved to be safe and well-tolerated in this population. Concerns have been raised regarding cost-effectiveness of palivizumab and thus, palivizumab prophylaxis is mainly limited to selected high-risk infants for the first RSV season. Long-lasting Mabs will be the next future approach in the prophylaxis of RSV hospitalization until a vaccine is developed.

Systematic Review of the Safety and Efficacy of Palivizumab among Infants and Young Children with Cystic Fibrosis

BACKGROUND

Respiratory syncytial virus (RSV) is a common pathogen in infants with cystic fibrosis (CF). The use of palivizumab prophylaxis for RSV infection as the standard of care for infants with CF remains controversial.

OBJECTIVE

To evaluate the efficacy of palivizumab in reducing the incidence of RSV hospitalization in children with CF who are younger than 2 years.

METHODS

Four electronic databases (PubMed, Embase, CINAHL, and CENTRAL) were searched from inception until January 31, 2017, for clinical studies investigating the use of palivizumab in infants with CF aged less than 2 years. The primary outcome was hospitalization rate due to RSV infection. Secondary outcomes included hospitalization for respiratory illness, length of hospital stay, safety (adverse effects), and cost-effectiveness of palivizumab prophylaxis.

RESULTS

The review included a total of 10 studies (six cohort studies, two before-and-after studies, one cross-sectional study, and one randomized controlled trial) involving 3891 patients with CF. Seven studies reported that palivizumab prophylaxis had a positive impact on the rate of RSV hospitalization. Five studies (n=3404) reported that palivizumab prophylaxis significantly reduced the rate of hospitalization due to RSV infection compared to no prophylaxis. One study (n=5) demonstrated patients with CF who received palivizumab had no RSV hospitalization. Another study showed infants with CF receiving palivizumab (n=117) had a lower risk of hospitalization for RSV infection compared with premature infants (gestational age < 35 completed weeks) who received palivizumab (n=4880).

CONCLUSIONS

Evidence from the literature suggests that palivizumab may have a potential role in reducing RSV hospitalization in children aged less than 2 years with CF. Given the lack of overall data, additional research is warranted to better understand the efficacy and safety of prophylactic palivizumab in infants with CF.

The cost-effectiveness of palivizumab in infants with cystic fibrosis in the Canadian setting: A decision analysis model

BACKGROUND

Children with cystic fibrosis (CF) are at higher risk of severe respiratory syncytial virus (RSV) infection, which can lead to a decline in lung function. A monoclonal antibody, palivizumab (PMB), effectively prevents RSV hospitalizations; however, the high cost of PMB, approximately C$10,000 per patient per RSV season, limits its widespread use. We assess the cost-effectiveness of PMB prophylaxis in CF children less than 2 y of age from the Canadian healthcare payer's perspective.

METHODS

In 2014, a Markov cohort model of CF disease and infant RSV infections in the Canadian setting was developed based on literature data. Infants were treated with monthly PMB injections over the 5-month RSV season. Lifetime health outcomes, quality-adjusted life years (QALYs) and 2013 $CAD costs, discounted at 5%, were estimated. Findings are summarized as incremental cost-effectiveness ratios (ICERs) and budget impact. Deterministic sensitivity analysis was conducted to assess parameter uncertainty.

RESULTS

Implementation of a hypothetical Canadian RSV prophylaxis program resulted in ICERs of C$652,560 (all CF infants) and C$157,332 (high-risk CF infants) per QALY gained and an annual budget impact of C$1,400,000 (all CF infants) and C$285,000 (high-risk CF infants). The analysis was highly sensitive to the probability of severe RSV, the degree of lung deterioration following infection, and the cost of PMB.

CONCLUSIONS

Our results suggest PMB is not cost-effective in Canada by commonly used thresholds. However, given the rarity of CF and relatively small budget impact, consideration may be given for the selective use of PMB for immunoprophylaxis of RSV in high-risk CF infants on a case-by-case scenario basis.

First versus second year respiratory syncytial virus prophylaxis in chronic lung disease (2005-2015)

Children aged <2 years with chronic lung disease (CLD) have a 10-fold higher risk for respiratory syncytial virus-positive hospitalization (RSVH) compared to healthy term infants. Based on the updated position statements, we compared respiratory-related illness hospitalization (RIH) and RSVH risks in CLD children who received palivizumab during the first year (FY) versus second year (SY) of life in the Canadian Registry of Palivizumab (CARESS). Demographic data were collected at enrolment and RIH events recorded monthly from 2005 to 2015. Eight hundred forty-seven FY and 450 SY children with CLD were identified. SY children had a lower gestational age (27 versus 29 weeks) and required more days of respiratory support (64 versus 43), oxygen therapy (108 versus 55), and length of stay (118 versus 73) during the neonatal course compared to FY children; all p < 0.0005. RIH rates were 12.2 (FY) and 18.2 (SY), and RSVH rates were 2.3 (FY) and 3.9 (SY). Cox regression showed similar hazards for both RIH (hazard ratio 0.9, 95% CI 0.6-1.6, p = 0.812) and RSVH (hazard ratio 1.1, 95% CI 0.4-2.9, p = 0.920).

CONCLUSIONS

SY and FY children had similar risks for RIH and RSVH. The findings imply that SY children with CLD are correctly selected for palivizumab based on neonatal illness severity and merit prophylaxis. What is Known: • Children with chronic lung disease have a 10-fold higher risk for RSV-positive hospitalization in comparison to healthy term infants and commonly receive palivizumab prophylaxis as a preventative measure against serious RSV-related lower respiratory tract infections. • The American Academy of Pediatrics [ 2 ] and the Canadian Paediatric Society [ 30 ] have recently modified their recommendations for RSV prophylaxis in children with chronic lung disease, limiting palivizumab to either those <32 weeks gestation or those in the first year of life who are oxygen dependent or require medical therapy for the treatment of their condition. What is New: • Children with chronic lung disease receiving an additional course of palivizumab in their second year of life were determined to be at similar risk for both respiratory illness-related hospitalization and RSV-positive hospitalization as palivizumab-naïve children enrolled in the first year of life in the Canadian Registry for palivizumab (CARESS). • CARESS physicians are correctly identifying high-risk children with chronic lung disease in their second year of life, whom they believe will benefit from an additional year of palivizumab prophylaxis, based on neonatal illness severity.

Down syndrome as risk factor for respiratory syncytial virus hospitalization: A prospective multicenter epidemiological study

BACKGROUND

Respiratory syncytial virus (RSV) infection in childhood, particularly in premature infants, is associated with significant morbidity and mortality.

OBJECTIVES

To compare the hospitalization rates due to RSV infection and severity of disease between infants with and without Down syndrome (DS) born at term and without other associated risk factors for severe RSV infection.

PATIENTS/METHODS

In a prospective multicentre epidemiological study, 93 infants were included in the DS cohort and 68 matched by sex and data of birth (±1 week) and were followed up to 1 year of age and during a complete RSV season.

RESULTS

The hospitalization rate for all acute respiratory infection was significantly higher in the DS cohort than in the non-DS cohort (44.1% vs 7.7%, P<.0001). Hospitalizations due to RSV were significantly more frequent in the DH cohort than in the non-DS cohort (9.7% vs 1.5%, P=.03). RSV prophylaxis was recorded in 33 (35.5%) infants with DS. The rate of hospitalization according to presence or absence of RSV immunoprophylaxis was 3.0% vs 15%, respectively.

CONCLUSIONS

Infants with DS showed a higher rate of hospitalization due to acute lower respiratory tract infection and RSV infection compared to non-DS infants. Including DS infants in recommendations for immunoprophylaxis of RSV disease should be considered.

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.

Down's syndrome is a risk factor for severe lower respiratory tract infection due to respiratory syncytial virus

AIM

Previous studies have suggested that Down's syndrome is an independent risk factor for severe respiratory infection due to respiratory syncytial virus (RSV). We compared the clinical characteristics of children with and without Down's syndrome hospitalised due to RSV.

METHODS

This retrospective cohort study compared data from hospitalisations due to RSV lower respiratory tract infections (LRTI) in children under 14 years of age with (n = 58) and without (n = 58) Down's syndrome.

RESULTS

The Down's group had longer hospital stays than the controls of six versus four days (p < 0.0001), even after adjusting for age, weeks of gestation at birth, presence of asthma, bronchopulmonary dysplasia, haemodynamically significant and nonsignificant congenital heart disease. This difference increased when only children under one year of age were analysed to 11 versus five days (p < 0.0001). Children with Down's syndrome were more likely to be admitted to intensive care unit (43.1% versus 22.4%, p = 0.017), need noninvasive mechanical ventilation (36.2% versus 13.7%, p = 0.005) and be prescribed antibiotics and steroids.

CONCLUSION

Children with Down's syndrome hospitalised due to RSV LRTI had longer hospital stays and worse clinical courses than controls, highlighting the need for RSV prophylaxis for children with Down's syndrome, especially under one year of age.

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.

Prevention of syncytial respiratory virus infection with palivizumab: descriptive and comparative analysis after 12 years of use

BACKGROUND

The use of palivizumab has been recommended to prevent syncytial respiratory virus (SRV) infection in vulnerable children.

METHODS

We performed a retrospective study of hospital admissions for bronchiolitis from 2000 to 2012 in the context of a prevention study with palivizumab in at-risk newborns.

RESULTS

A total of 952 children (59.5% males) were admitted due to bronchiolitis. Admissions occurred in younger children in the SRV+ cases compared to the SRV- cases (P<0.001). Additionally, 641 children were treated with Palivizumab at our service. Sixty of these children (9.8%) were admitted due to bronchiolitis and SRV was detected in 22 of them (3.4%). Fifty (7.8%) had underlying diseases, 6 (0.9%) presented with a history of perinatal infection and 20 (3.12%) had been part of a multiple birth. The treated children with some additional risk factor presented a greater risk of admission due to bronchiolitis (OR=1.99, P=0.045); however, this was not observed for admissions due to SRV (P=0.945).

CONCLUSIONS

Children treated with Palivizumab showed a lower rate of SRV infection, despite having more risk factors associated with a higher risk of infection or complications.

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.

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.

Risk of respiratory syncytial virus infection in preterm infants: reviewing the need for prevention

Premature infants are at substantial risk for a spectrum of morbidities that are gestational age dependent. Respiratory syncytial virus (RSV) infection is most common in the first two years of life with the highest burden in children aged <6 months. Preterm infants ≤35 weeks' gestation are handicapped by incomplete immunological and pulmonary maturation and immature premorbid lung function with the added risk of bronchopulmonary dysplasia. Superimposed RSV infection incites marked neutrophilic airway inflammation and innate immunological responses that further compromise normal airway modeling. This review addresses the epidemiology and burden of RSV disease, focusing on the preterm population. Risk factors that determine RSV-disease severity and hospitalization and the impact on healthcare resource utilization and potential long-term respiratory sequelae are discussed. The importance of disease prevention and the evidence-based rationale for prophylaxis with palivizumab is explored, while awaiting the development of a universal vaccine.

Is palivizumab effective as a prophylaxis of respiratory syncytial virus infections in cystic fibrosis patients? A meta-analysis

BACKGROUND

Infections by respiratory syncytial virus (RSV) are more severe in patients with cystic fibrosis (CF), and many CF units use palivizumab as prophylaxis; however, information about palivizumab efficacy in CF patients is almost lacking.

METHODS

A literature search up to December 2012 on the morbidity of RSV bronchiolitis in CF patients and on the safety and efficacy of palivizumab in those patients was performed. A random-effects meta-analysis was conducted for those studies meeting pre-specified search criteria. Historical controls were allowed.

RESULTS

The number of patients who received palivizumab was 354 and the hospital admission rate was 0.018 (95% CI 0.0077-0.048). The corresponding number in the non-treated groups was 463 patients with an admission rate of 0.126 (95% CI 0.086-0.182) (Q=13.9; p<0.001).

CONCLUSION

Palivizumab may have a role in the prevention of severe lower airway infection by RSV in CF patients.

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.

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.

Epidemiological and clinical data of hospitalizations associated with respiratory syncytial virus infection in children under 5 years of age in Spain: FIVE multicenter study

BACKGROUND

Respiratory syncytial virus (RSV) is an important pathogen in lower respiratory tract infections (LRTI) in infants, but there are limited data concerning patients with underlying conditions and children older than 2 years of age.

METHODS

We have designed a prospective observational multicenter national study performed in 26 Spanish hospitals (December 2011-March 2012). Investigational cases were defined as children with underlying chronic diseases and were compared with a group of previously healthy children (proportion 1:2). Clinical data were compared between the groups.

RESULTS

A total of 1763 children hospitalized due to RSV infection during the inclusion period were analyzed. Of them, 225 cases and 460 healthy children were enrolled in the study. Underlying diseases observed were respiratory (64%), cardiovascular (25%), and neurologic (12%), as well as chromosomal abnormalities (7·5%), immunodeficiencies (6·7%), and inborn errors of metabolism (3·5%). Cases were statistically older than previously healthy children (average age: 16·3 versus 5·5 months). Cases experienced hypoxemia more frequently (P < 0·001), but patients with respiratory diseases required oxygen therapy more often (OR: 2·99; 95% CI: 1·03-8·65). Mechanical ventilation was used more in patients with cardiac diseases (OR: 3·0; 95% CI: 1·07-8·44) and in those with inborn errors of metabolism (OR: 12·27; 95% CI: 2·11-71·47). This subgroup showed a higher risk of admission to the PICU (OR: 6·7, 95% CI: 1·18-38·04). Diagnosis of pneumonia was more frequently found in cases (18·2% versus 9·3%; P < 0·01).

CONCLUSIONS

A significant percentage of children with RSV infection have underlying diseases and the illness severity is higher than in healthy children.

Increased risk of RSV infection in children with Down's syndrome: clinical implementation of prophylaxis in the European Union

Prospective cohort studies show that Down's syndrome (DS) is an independent risk factor for hospitalization for RSV bronchiolitis. It is unknown whether this observation has been translated into specific management for DS children. The primary goal was to assess the knowledge of healthcare providers in the European Union about RSV infection in DS children and to determine whether it influenced the implementation of prophylaxis. DS caregivers were surveyed using a standardized questionnaire, and country-specific guidelines were obtained. Fifty-three caregivers participated. Thirty-nine (86.7%) had knowledge of the increased risk of severe RSV infection in DS children, and 30 (71.4%) graded that it was important to have a statement on the use of RSV prophylaxis in existing guidelines. Twenty-eight participants had a local DS guideline; hard copies of twelve unique guidelines were obtained. Only one (8.3%) contained a statement on RSV prophylaxis for DS, and five considered such a statement for the next version. Conclusion. Most pediatricians had knowledge that DS children have an increased risk of severe RSV infection. Despite the lack of a specific RSV prophylaxis trial in DS, they felt that a statement on RSV prophylaxis in DS guidelines was important, but this was rarely present in current guidelines.

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.

Spectrum of viral infections in patients with cystic fibrosis

This review explores the extensive influence of viral infections leading to chronic deterioration of lung function in patients with cystic fibrosis (CF). The mechanisms how viral agents affect the pathogenesis as well as the inflammatory and immune response of CF are discussed. Viral infections of the upper and lower respiratory tract due to viruses in CF patients and methods for diagnosis of respiratory viruses are described in detail. The importance of respiratory and non-respiratory viral agents for the pathogenesis, especially for the exacerbation of bacterial lower respiratory tract infections and course of CF, is stressed, especially emphasizing respiratory syncytial virus, influenza virus, rhinovirus, and human herpes viruses. Possible harmful effects of further viruses like adenovirus, bocavirus, coronavirus, metapneumovirus, parainfluenzavirus on the lung function of CF patients are discussed. The potential use of adenovirus-based vectors for somatic gene therapy is mentioned.