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

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..

Efficacy of Palivizumab Immunoprophylaxis for Reducing Severe RSV Outcomes in Children with Immunodeficiencies: A Systematic Review

BACKGROUND

Palivizumab is recommended for prevention of severe respiratory syncytial virus (RSV) disease in immunocompromised children, despite a lack of strong supporting evidence. The recent approval of substitute RSV-neutralizing monoclonal antibodies against RSV, offers an opportunity to synthesize the most current evidence supporting the palivizumab standard of care.

OBJECTIVE

To evaluate the efficacy of palivizumab in preventing acute respiratory tract infection- or RSV-related hospitalization, or mortality in immunocompromised children.

METHODS

We searched Ovid MEDLINE and EMBASE for published clinical studies that investigated outcomes of palivizumab use in children. We included clinical trials, cohort studies, and case-control studies. The primary outcomes were RSV-related or respiratory viral infection-related hospitalizations, or RSV-related mortality. This systematic review was registered in PROSPERO (ID CRD42021248619) and is reported in accordance with the PRISMA guidelines.

RESULTS

From the 1993 records, six studies were eligible and included, for a total of 625 immunocompromised children with an heterogeneous composition of primary and acquired immunodeficiencies enrolled from palivizumab programs. There were no intervention studies. None of the studies included a control group. RSV hospitalizations were infrequent (0%-3.1% of children). Most children included received palivizumab, although one study (n = 56) did not specify how many received palivizumab. RSV mortality was neither observed, in three studies, nor reported, in three other studies.

CONCLUSIONS

The evidence supporting the use of palivizumab for prevention of severe RSV disease in immunocompromised children remains extremely limited and appears insufficient to justify prioritizing this intervention as the current standard of care over alternative interventions.

Exploring the adoption of less restricted criteria for respiratory syncytial virus prophylaxis in late preterm infants: insights from a retrospective analysis

Background

Preterm infants born between 33 and 35 weeks of gestational age (wGA) have been considered a "major underserved population" and ineligible to receive palivizumab (PLV), the only drug authorized to date for respiratory syncytial virus (RSV) prophylaxis, by current international guidelines. In Italy, such a vulnerable population is currently eligible for prophylaxis, and, in our region, specific risk factors are taken into consideration (SIN_Lazio score) to target prophylaxis for those at highest risk. Whether the adoption of less or more restrictive eligibility criteria for PLV prophylaxis would translate into differences in bronchiolitis and hospitalization incidence is not known.

Materials and methods

A retrospective analysis was conducted in 296 moderate-to-late preterm infants (born between 33 and 35⁺⁶ weeks) who were being considered for prophylaxis in two epidemic seasons: 2018-2019 and 2019-2020. The study participants were categorized according to both the SIN_Lazio score and the Blanken risk scoring tool (BRST), which was found to reliably predict RSV-associated hospitalization in preterm infants on the basis of three risk factor variables.

Results

Based on the SIN_Lazio score, approximately 40% of infants (123/296) would meet the criteria to be eligible for PLV prophylaxis. In contrast, none of the analyzed infants would be considered eligible for RSV prophylaxis on the basis of the BRST. A total of 45 (15.2%) bronchiolitis diagnoses were recorded on average at 5 months of age in the overall population. Almost seven out of 10 (84/123) patients exhibiting ≥3 risk factors to be eligible for RSV prophylaxis according to SIN_Lazio criteria would not be receiving PLV if they were categorized on the basis of the BRST. Bronchiolitis occurrence in patients with a SIN_Lazio score ≥3 was approximately 2.2 times more likely than that in patients with a SIN_Lazio score <3. PLV prophylaxis has been associated with a 91% lower risk of requiring a nasal cannula.

Conclusion

Our work further supports the need for targeting late preterm infants for RSV prophylaxis and calls for an appraisal of the current eligibility criteria for PLV treatment. Therefore, adopting less restrictive criteria may ensure a comprehensive prophylaxis of the eligible subjects, thus sparing them from avoidable short- and long-term consequences of RSV infection.

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.

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.

Hospitalisations due to respiratory syncytial virus infection in children with Down syndrome before and after palivizumab recommendation in Japan

AIM

Down syndrome has been considered an independent risk factor for respiratory syncytial virus (RSV) infection. Palivizumab, an anti-RSV humanised monoclonal antibody, was currently approved for all children with Down syndrome in Japan. To investigate the change in RSV-associated hospitalisation (RSVH) rates before and after the universal approval of palivizumab in Japan in 2013, we conducted a nationwide retrospective survey.

METHODS

We conducted a nationwide, retrospective, questionnaire survey across paediatric institutions in Japan. The recruited children with Down syndrome were divided into two groups: those born April 2010 to March 2013 (2010-2012 cohort) and those born April 2013 to March 2016 (2013-2015 cohort).

RESULTS

Of the 664 institutions, 321 (48.3%) replied, and a total of 3929 children with Down syndrome were registered. The percentage of children who received palivizumab increased from 49.2% to 82.2%. The cumulative RSVH rate showed a decreased trend in the 2013-2015 cohort (OR, 0.83; 95%CI, 0.63-1.10), while the rate of these children (without CHD and born at a gestational age ≥ 36 weeks) was significantly decreased in the 2013-2015 cohort (OR, 0.56; 95%CI, 0.34-0.92).

CONCLUSION

The cumulative RSVH rate tended to be decreased after approval for all children with Down syndrome although the result was not significant.

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.

Efficacy and safety of interferon on neonates with respiratory syncytial virus pneumonia

Respiratory syncytial virus (RSV) pneumonia is a leading cause of hospitalization and mortality among neonates worldwide, and there are currently no specific clinical treatments for RSV infection. Interferons (IFNs) possess broad-spectrum antiviral properties, and the present study aimed to evaluate the efficacy and safety of IFN-α1b for the treatment of neonatal RSV pneumonia. Neonates with RSV pneumonia were divided into the treatment (126 neonates) and control (160 neonates) groups, the former of which were treated with IFN. Aside from IFN administration, both groups received the same routine treatments. There were no significant differences in patient characteristics between the two groups. All neonates in the two groups displayed symptoms such as a cough (93.0%), tachypnea (90.1%), perilabial cyanosis (67.8%), choking on milk (62.9%) and moist rales (58.4%), and no significant differences in the occurrence of these symptoms were observed between the groups (P>0.05). The percentage of cases with bacterial co-infection was 66.8% (191/286), and the bacterial species in the spectrum primarily included Escherichia coli (21.5%), Klebsiella pneumonia (20.4%), Staphylococcus aureus (17.2%), Acihetobacter baumanii (13.1%) and Pseudomonas aeruginosa (9.9%). There were no significant differences in the co-infection rate or bacterial spectrum between the two groups. The remission time of cough, tachypnea, choking on milk, perilabial cyanosis, moist rales and oxygen inhalation in the treatment group was significantly lower compared with the control group (P<0.05). Although the hospitalization time in the treatment group was shorter compared with the control group, the difference was not significant. There were two patients in the treatment group that developed fever within 2-6 h after receiving IFN-α1b, though no other adverse effects were observed. In conclusion, IFN-α1b treatment improved the symptoms associated with neonatal RSV pneumonia with minimal adverse effects.

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.

Expert consensus on palivizumab use for respiratory syncytial virus in developed countries

Respiratory syncytial virus (RSV) infection is a leading cause of hospitalisation in early childhood and palivizumab is the only licensed intervention for prevention. Palivizumab guidelines should reflect the latest evidence, in addition to cost-effectiveness and healthcare budgetary considerations. RSV experts from Europe, Canada and Israel undertook a systematic review of the evidence over the last 5 years and developed recommendations regarding prophylaxis in industrialised countries. Almost 400 publications were reviewed. This group recommended palivizumab for: preterm infants (<29 and ≤31 weeks gestational age [wGA] and ≤9 and ≤6 months of age, respectively; high-risk 32-35wGA), former preterm children ≤24 months with chronic lung disease/bronchopulmonary dysplasia, children ≤24 months with significant congenital heart disease; and other high-risk populations, such as children ≤24 months with Down syndrome, pulmonary/neuromuscular disorders, immunocompromised, and cystic fibrosis. Up to 5 monthly doses should be administered over the RSV season. It is our impression that the adoption of these guidelines would help reduce the burden of RSV.

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 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.

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.

Human respiratory syncytial virus and hospitalization in young children in Italy

BACKGROUND

Human respiratory syncytial virus (hRSV) is ubiquitous and causes respiratory diseases in both children and adults. Worldwide, hRSV pneumonia is the second cause of postnatal infant death after malaria. Given the high impact in terms of morbidity, mortality and costs, especially in the pediatric population, hRSV is recognized as a global health problem and the WHO, in view of the availability of new vaccines, has urged an active surveillance program of virus-related infections. The aim of this study has been to evaluate the impact of hRSV infections in the Italian population, particularly the pediatric one, in terms of hospitalizations.

METHODS

In the period 2001-2014, Hospital Discharge Records (HDRs) with the following diagnosis codes included in the primary diagnosis were evaluated: 466.11 (hRSV bronchiolitis), 480.1 (hRSV pneumonia) and 796 (hRSV). HDRs were supplied by the National Archive of HDRs data, Ministry of Health.

RESULTS

During the period 2001-2014, 57,656 hospital admissions due to hRSV pathologies were performed. Most hospitalizations (88.8%) involved patients with less than 1 year of age. Considering only primary diagnosis, 93% of the admissions were due to bronchiolitis, 5% to pneumonia and 2% to not otherwise specified hRSV infections. In the period 2001-2014, the hospitalization rate in 0-2 years old children, was equal to 224.8, 9.6 and 4.6/100,000 for hRSV bronchiolitis, hRSV pneumonia and not otherwise specified hRSV infection, respectively.

CONCLUSIONS

This study confirms the high impact of hRSV on the pediatric population in the age class 0-4 years, with a peak in the first 12 months of life. Most hospitalizations were urgent, although the duration of the hospital stay was for the most part less than a week, with ordinary discharge at home. Pending the conclusion of ongoing clinical trials on different hRSV vaccine types, it is extremely important to have updated data on the impact of hRSV-related pathologies in the various age groups.

Palivizumab prophylaxis for respiratory syncytial virus in infants with cystic fibrosis: is there a need?

Respiratory syncytial virus (RSV) infection in cystic fibrosis (CF) infants is associated with significant morbidities. This study's objective is to evaluate the effectiveness and adverse events related to palivizumab (PVZ) in CF infants. Data on respiratory-related illness (RIH) and RSV hospitalizations (RSVH) were collected retrospectively in CF infants aged < 2 years in Alberta, Canada, from 2000 to 2017. Logistic regression models were used to compare the odds of RSVH or RIH in PVZ infants from the Canadian registry of palivizumab (CARESS) versus untreated (UPVZ) infants from Alberta, after adjusting for potential confounders. Illness severity was compared between cohorts using χ² and t tests. A total of 267 CF infants were included: 183 (PVZ) and 84 (UPVZ). A total of 53.3% were tested for RSV. Fifty-five infants experienced a RIH and 10 had a RSVH. The PVZ cohort experienced similar odds of RSVH but decreased odds of RIH versus UPVZ, adjusting for gestational age, birth weight, birth during RSV peak months, and presence of siblings (Exp(B) = 0.23 [0.11-0.49], p < 0.0005). In RSVH-related subjects, PVZ subjects experienced shorter length of overall stay (LOS; t = 2.39 [df = 7], p = 0.048). In those with a RIH, the PVZ group had shorter overall intensive care unit (t = 3.52 [df = 15], p = 0.003) and hospital LOS (t = 2.11 [df = 52], p = 0.04). No serious adverse events were related to PVZ. The odds of RSVH were similar between groups, but PVZ subjects had decreased odds of RIH. The low number of RSV tests performed may explain the similarity in RSVH rates. Significant differences in LOS may indicate decreased RSVH and RIH illness severity in the PVZ versus UPVZ groups.

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.