Risk scoring tool to predict respiratory syncytial virus hospitalisation in premature infants

Maternal Risk Factors for Respiratory Syncytial Virus Lower Respiratory Tract Infection in Otherwise Healthy Preterm and Term Infants: A Systematic Review and Meta-analysis

BACKGROUND/OBJECTIVE

To date, there is no published, formal assessment of all maternal risk factors for respiratory syncytial virus lower respiratory tract infection (RSV-LRTI) in infants. A systematic literature review and meta-analysis were undertaken to ascertain: What maternal risk factors are associated with an increased risk of RSV-LRTI in infants?

METHODS

The systematic literature review used explicit methods to identify, select and analyze relevant data. PubMed, Embase and the Cochrane Library were searched (November 2022) using terms regarding: (1) RSV/LRTI; (2) risk factors; (3) pregnant/postpartum population. Bayesian meta-analysis compared RSV hospitalization (RSVH) risk in infants born to mothers with or without certain risk factors.

RESULTS

A total of 2353 citations were assessed and 20 were included in the final review (10 individual studies; 10 pooled analyses). In 10 studies examining infants (<1 year) without comorbidities (primary outcome), 10 maternal risk factors were associated with RSV-LRTI/RSVH in multivariate analyses. Meta-analysis revealed smoking while pregnant increased infant RSVH risk by 2.01 (95% credible interval: 1.52-2.64) times, while breast-feeding was protective (0.73, 95% credible interval: 0.58-0.90). Risk scoring tools have reported that maternal risk factors contribute between 9% and 21% of an infant's total risk score for RSVH.

CONCLUSIONS

A greater understanding of maternal risk factors and their relative contribution to infant RSV-LRTI will enable more accurate assessments of the impact of preventive strategies.

Personalized Infant Risk Prediction for Severe Respiratory Syncytial Virus Lower Respiratory Tract Infection Requiring Intensive Care Unit Admission

Background

Currently, there are no available tools to identify infants at the highest risk of significant morbidity and mortality from respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) who would benefit most from RSV prevention products. The objective was to develop and internally validate a personalized risk prediction tool for use among all newborns that uses readily available birth/postnatal data to predict RSV LRTI requiring intensive care unit (ICU) admission.

Methods

We conducted a population-based birth cohort study of infants born from 1995 to 2007, insured by the Tennessee Medicaid Program, and who did not receive RSV immunoprophylaxis during the first year of life. The primary outcome was severe RSV LRTI requiring ICU admission during the first year of life. We built a multivariable logistic regression model including demographic and clinical variables available at or shortly after birth to predict the primary outcome.

Results

In a population-based sample of 429 365 infants, 713 (0.2%) had severe RSV LRTI requiring ICU admission. The median age of admission was 66 days (interquartile range, 37-120). Our tool, including 19 variables, demonstrated good predictive accuracy (area under the curve, 0.78; 95% confidence interval, 0.77-0.80) and identified infants who did not qualify for palivizumab, based on American Academy of Pediatrics guidelines, but had higher predicted risk levels than infants who qualified (27% of noneligible infants with >0.16% predicted probabilities [lower quartile for eligible infants]).

Conclusions

We developed a personalized tool that identified infants at increased risk for severe RSV LRTI requiring ICU admission, expected to benefit most from immunoprophylaxis.

Risk factors for severe respiratory syncytial virus infection during the first year of life: development and validation of a clinical prediction model

BACKGROUND

Novel immunisation methods against respiratory syncytial virus (RSV) are emerging, but knowledge of risk factors for severe RSV disease is insufficient for optimal targeting of interventions against them. Our aims were to identify predictors for RSV hospital admission from registry-based data and to develop and validate a clinical prediction model to guide RSV immunoprophylaxis for infants younger than 1 year.

METHODS

In this model development and validation study, we studied all infants born in Finland between June 1, 1997, and May 31, 2020, and in Sweden between June 1, 2006, and May 31, 2020, along with the data for their parents and siblings. Infants were excluded if they died or were admitted to hospital for RSV within the first 7 days of life. The outcome was hospital admission due to RSV bronchiolitis during the first year of life. The Finnish study population was divided into a development dataset (born between June 1, 1997, and May 31, 2017) and a temporal hold-out validation dataset (born between June 1, 2017, and May 31, 2020). The development dataset was used for predictor discovery and selection in which we screened 1511 candidate predictors from the infants', parents', and siblings' data, and developed a logistic regression model with the 16 most important predictors. This model was then validated using the Finnish hold-out validation dataset and the Swedish dataset.

FINDINGS

In total, there were 1 124 561 infants in the Finnish development dataset, 130 352 infants in the Finnish hold-out validation dataset, and 1 459 472 infants in the Swedish dataset. In addition to known predictors such as severe congenital heart defects (adjusted odds ratio 2·89, 95% CI 2·28-3·65), we confirmed some less established predictors for RSV hospital admission, most notably oesophageal malformations (3·11, 1·86-5·19) and lower complexity congenital heart defects (1·43, 1·25-1·63). The prediction model's C-statistic was 0·766 (95% CI 0·742-0·789) in Finnish data and 0·737 (0·710-0·762) in Swedish validation data. The infants in the highest decile of predicted RSV hospital admission probability had 4·5 times higher observed risk compared with others. Calibration varied according to epidemic intensity. The model's performance was similar to a machine learning (XGboost) model using all 1511 candidate predictors (C-statistic in Finland 0·771, 95% CI 0·754-0·788). The prediction model showed clinical utility in decision curve analysis and in hypothetical number needed to treat calculations for immunisation, and its C-statistic was similar across different strata of parental income.

INTERPRETATION

The identified predictors and the prediction model can be used in guiding RSV immunoprophylaxis in infants, or as a basis for further immunoprophylaxis targeting tools.

FUNDING

Sigrid Jusélius Foundation, European Research Council, Pediatric Research Foundation, and Academy of Finland.

A new cost-utility analysis assessing risk factor-guided prophylaxis with palivizumab for the prevention of severe respiratory syncytial virus infection in Italian infants born at 29-35 weeks' gestational age

Since the last Italian cost-utility assessment of palivizumab in 2009, new data on the burden of respiratory syncytial virus (RSV) and an International Risk Scoring Tool (IRST) have become available. The objective of this study was to provide an up-to-date cost-utility assessment of palivizumab versus no prophylaxis for the prevention of severe RSV infection in otherwise healthy Italian infants born at 29-31 weeks' gestational age (wGA) infants and those 32-35wGA infants categorized as either moderate- or high-risk of RSV-hospitalization (RSVH) by the IRST. A decision tree was constructed in which infants received palivizumab or no prophylaxis and then could experience: i) RSVH; ii) emergency room medically-attended RSV-infection (MARI); or, iii) remain uninfected/non-medically attended. RSVH cases that required intensive care unit admission could die (0.43%). Respiratory morbidity was considered in all surviving infants up to 18 years of age. Hospitalization rates were derived from Italian data combined with efficacy from the IMpact-RSV trial. Palivizumab costs were calculated from vial prices (50mg: €490.37 100mg: €814.34) and Italian birth statistics combined with a growth algorithm. A lifetime horizon and healthcare and societal costs were included. The incremental cost-utility ratio (ICUR) was €14814 per quality-adjusted life year (QALY) gained in the whole population (mean: €15430; probability of ICUR being <€40000: 0.90). The equivalent ICURs were €15139 per QALY gained (€15915; 0.89) for 29-31wGA infants and €14719 per QALY gained (€15230; 0.89) for 32-35wGA infants. The model was most sensitive to rates of long-term sequelae, utility scores, palivizumab cost, and palivizumab efficacy. Palivizumab remained cost-effective in all scenario analyses, including a scenario wherein RSVH infants received palivizumab without a reduction in long-term sequelae and experienced a 6-year duration of respiratory morbidity (ICUR: €27948 per QALY gained). In conclusion, palivizumab remains cost-effective versus no prophylaxis in otherwise healthy Italian preterm infants born 29-35wGA. The IRST can help guide cost-effective use of palivizumab in 32-35wGA infants.

Understanding Policy Decisions and Their Implications Regarding Preventive Interventions for Respiratory Syncytial Virus (RSV) Infection in Canadian Infants: A Primer for Nurses

Respiratory syncytial virus (RSV) is a leading cause of morbidity and hospitalization in young children, and prevention is the primary management strategy. At present, palivizumab, a monoclonal antibody providing immediate passive immunity, rather than a vaccine that induces active immunity, is the only preventive intervention used in routine practice internationally. In Canada, access varies across the country. Prophylaxis policies are mainly driven by cost-effectiveness analyses, and it is crucial that the full costs and benefits of any intervention are captured. Positive results from a new Canadian cost-effectiveness analysis of palivizumab will help address the current inequality in use while providing a framework for future models of RSV preventives. Nurses are the principal educators for parents about the risks of childhood RSV and optimal prevention via basic hygiene, behavioral and environmental measures, and seasonal prophylaxis. Nurses should be provided not only with regular, up-to-date, and accurate information on RSV and the clinical aspects of emerging interventions but be informed on the decision-making governing the use of preventive strategies.

Respiratory Syncytial Virus Infections in Neonates: A Persisting Problem

Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infections in young infants. It is an enveloped, single-stranded, nonsegmented, negative-strand RNA virus, a member of the family Pneumoviridae. Globally, RSV is responsible for 2.3% of deaths among neonates 0-27 days of age. Respiratory syncytial virus infection is most common in children aged below 24 months. Neonates present with cough and fever. Respiratory syncytial virus-associated wheezing is seen in 20% infants during the first year of life of which 2-3% require hospitalization. Reverse transcriptase polymerase chain reaction (RT-PCR) gives fast results and has higher sensitivity compared with culture and rapid antigen tests and are not affected by passively administered antibody to RSV. Therapy for RSV infection of the LRT is mainly supportive, and preventive measures like good hygiene and isolation are the mainstay of management. Standard precautions, hand hygiene, breastfeeding and contact isolation should be followed for RSV-infected newborns. Recent AAP guidelines do not recommend pavilizumab prophylaxis for preterm infants born at 29-35 weeks without chronic lung disease, hemodynamically significant congenital heart disease and coexisting conditions. RSV can lead to long-term sequelae such as wheezing and asthma, associated with increased healthcare costs and reduced quality of life.

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.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Real-World Studies of Respiratory Syncytial Virus Hospitalizations among Moderate/Late Preterm Infants Exposed to Passive Immunoprophylaxis with Palivizumab

This article aims to assess the real-world effectiveness of palivizumab immunoprophylaxis against respiratory syncytial virus (RSV)-associated hospitalization (RSVH) rates in otherwise healthy moderate/late preterm infants and discuss the role of palivizumab in preventing acute and long-term outcomes. We identified studies in the PubMed and Embase databases that reported patient-level data on (1) exposure to palivizumab in preterm infants born between 29 and 35 weeks of gestational age (or subsets within this range) ≤ 2 years of chronological age, and (2) the outcome of RSVH. Six studies assessed RSVH in infants this gestational age who had been exposed or not to palivizumab and reported patient-level data. Exposure was associated with a reduction in RSVH rates that was comparable to the reduction seen in controlled clinical trials (weighed mean 4.0-fold reduction). RSV immunoprophylaxis in preterm infants within 29 to 35 weeks of gestational age is associated with a considerably lower burden of RSVH. KEY POINTS: · RSV is the leading cause of lower respiratory tract infection hospitalization in infants.. · Palivizumab prevents RSVH in a real-world scenario.. · Immunoprophylaxis should be used in high-risk infants..

Summer Hospitalization and Bronchial Asthma Make Treatment of Respiratory Syncytial Virus Infection Difficult: A Retrospective Study in Japan

In recent years, epidemics of respiratory syncytial virus (RSV) have been seen in the summer in Japan. Patients hospitalized in the summer used a high-flow oxygen administration device more frequently than patients hospitalized in the winter. This study was a retrospective study to examine the variables associated with duration of oxygen therapy and severe cases. Subjects were pediatric patients diagnosed with RSV infection and hospitalized for treatment during the 5 years from April 2014 to March 2019. Data from 292 patients were analyzed. Duration of oxygen therapy was significantly associated with bronchial asthma (partial regression coefficient: 0.897, P = .004). Hospitalization in summer was significantly associated with severe condition (adjusted odds ratio: 4.07, 95% confidence interval: 1.16-14.27). The present study showed that bronchial asthma is a risk factor for prolonged oxygen therapy and infection in summer is a risk factor for progression to severe condition in cases of RSV infection.

Comparison of the Canadian vs. the international risk scoring tool for respiratory syncytial virus prophylaxis in moderate-to-late preterm infants

AIM

The study objective was to compare the Pediatric Investigators Collaborative Network on Infections in Canada risk scoring tool (CRST) that determines need for respiratory syncytial virus (RSV) prophylaxis in infants 33-35 weeks gestational age during the RSV season, with the newly developed international risk scoring tool (IRST).

METHODS

Children 33-35 weeks gestational age born during the 2018-2021 RSV seasons were prospectively identified following birth and scored with the validated CRST and IRST, that comprises seven and three variables respectively, into low- moderate- and high-risk groups that predict RSV-related hospitalization. Correlations between total scores on the two tools, and cut-off scores for the low-, moderate- and high-risk categories were conducted using the Spearman rank correlation.

RESULTS

Over a period of 3 RSV seasons, 556 infants were scored. Total risk scores on the CRST and the IRST were moderately correlated (r_s  = 0.64, p < 0.001). A significant relationship between the risk category rank on the CRST and the risk category rank on the IRST (r_s= 0.53; p < 0.001) was found. The proportion of infants categorized as moderate risk for RSV hospitalization by the CRST and IRST were 19.6% (n = 109) and 28.1% (n = 156), respectively.

CONCLUSION

The IRST may provide a time-efficient scoring alternative to the CRST with three vs. seven variables, and it selects a larger number of infants who are at moderate risk for RSV hospitalization for prophylaxis. A cost-utility analysis is necessary to justify country-specific use of the IRST, while in Canada a cost comparison is necessary between the IRST vs. the currently approved CRST prior to adoption.

An outbreak of RSV infections in a neonatology clinic during the RSV-season

Background

Respiratory syncytial virus (RSV) is the predominant cause of lower respiratory tract infections (LRTI) in infancy. Preterm infants with bronchopulmonary dysplasia (BPD) are at the highest risk of severe RSV-LRTI. This is a retrospective study that analyses a nosocomial outbreak of RSV infections in the Neonatology clinic of the University Hospital of Obstetrics and Gynecology, Sofia, 2019.

Methods

Two groups of infants without contact between them were diagnosed with RSV-infection: 14 infants were treated in the Department for healthy newborns – Group 1, and 7 preterm infants were treated in the Neonatal Intensive Care Unit (NICU) – Group 2. The detection of RSV was performed using Real-Time PCR in nasal/throat swabs.

Results

Respiratory symptoms occurred 2–5 days after discharge in 14 of 148 healthy term infants born February 5 to 18, 2019; 12 babies were re-hospitalized with LRTI and recovered in a few days. RSV-PCR was positive in 6 infants, while in the others, RSV etiology was suggested, due to similar symptoms and contact between them.

The first NICU patient with RSV-LRTI was one of the 26 gestational weeks (GW) twins, who had severe BPD. The other twin was always discharged home without LRTI-symptoms. In the period February 19 to March 15, 2019, 26 premature babies born at 26–34 GW, were tested for RSV (33 nasal/throat swabs). They received a first or subsequent palivizumab injection. We identified 11 positive samples in 7 of the babies. Despite the clinical recovery, the second RSV-PCR remained positive in 4 babies. Six of the 7 NICU patients had symptoms of LRTI, and two of them needed mechanical ventilation. Six babies were discharged home after stabilization, one was transferred to the Pediatric department for further treatment of BPD and later discharged too.

Conclusions

This was the most serious outbreak of RSV infections in neonates since the RSV-PCR diagnostic in Bulgaria was introduced. The course of RSV-LRTI was severe in extremely preterm patients with underlying BPD. So, routine in-hospital RSV-prophylaxis with palivizumab should be considered for infants at the highest risk.

Risk Factors for Respiratory Syncytial Virus Infections in Moderate/Late Premature Infants in Turkey: A Prospective Multicenter Epidemiological Study

OBJECTIVE

Respiratory syncytial virus (RSV) is one of the most prevalent causes of lower respiratory tract infection (LRTI). The primary objective of this study is to provide the risk modelling of confirmed RSV infection in children who were born preterm at 29 to 35 weeks of gestational age and presented with LRTI.

STUDY DESIGN

This prospective, multicenter study was performed between October 2015 and March 2017. Premature infants born with gestational age between 29 and 35 weeks that were ≤2 years of age at the beginning of the RSV season and admitted to the hospital with clinical findings of LRTI during the season were included. RSV-positive and -negative infants were compared in terms of demographic features, risk factors, and requirement of hospitalization.

RESULTS

RSV positive group was lower than RSV negative group and ratio of ≤3 months age at admission was significant higher in RSV (+) group. RSV-positive infants were found to be significantly born during or 3 months prior to RSV season. The rate and duration of hospitalization and need for mechanical ventilation were significantly higher in RSV positive infants. The rate and duration of hospitalization in RSV positive patients was related to the chronological age.

CONCLUSION

This study showed that preterm infants with RSV-associated LRTI significantly needed more hospitalization, intensive care admission, and mechanical ventilation. In addition need of hospitalization and duration of hospitalization were significant higher in ≤3 months of age. Therefore, we suggest the importance of palivizumab prophylaxis in infants ≤ 3 months chronological age, especially during the RSV season.

Role of age and birth month in infants hospitalized with RSV-confirmed disease in the Valencia Region, Spain

Background

RSV is the leading cause of hospital admissions in infants and the principal cause of bronchiolitis in young children. There is a lack of granular data on RSV‐associated hospitalization per season using laboratory confirmed results. Our current study addresses this issue and intends to fill this gap.

Methods

The study was conducted from 2014 through 2018, in 4 to 10 hospitals in the Valencia Region, Spain. Infants included in this study were admitted in hospital through the Emergency Department with a respiratory complaint and tested by RT‐PCR for RSV in a central laboratory.

Results

Incidence rates of RSV‐associated hospitalization varied by season and hospital. Overall, the highest incidence rates were observed in 2017/2018. RSV‐associated hospitalization was highest in infants below 3 months of age and in those born before or at the beginning of the RSV season. Almost 54% of total infants hospitalized with laboratory confirmed RSV were found to be born outside the season, from April to October. The RSV positivity rate by ICD‐10 discharged codes varied by season and age with results from 48% to 57% among LRI (J09‐J22).

Conclusion

The study was instrumental in bringing forth the time unpredictability of RSV epidemics, the critical impact of age, and the comparable distribution of RSV‐associated hospitalization in infants born on either side of the RSV season. These data could help in better characterization of the population that drives the healthcare burden and is crucial for the development of future immunization strategies, especially with upcoming vaccines in against RSV.

Esophageal Atresia and Respiratory Morbidity

BACKGROUND AND OBJECTIVES

Respiratory diseases are common in children with esophageal atresia (EA), leading to increased morbidity and mortality in the first year. The primary study objective was to identify the factors associated with readmissions for respiratory causes in the first year in EA children.

METHODS

A population-based study. We included all children born between 2008 and 2016 with available data and analyzed factors at birth and 1 year follow-up. Factors with a P value <.10 in univariate analyses were retained in logistic regression models.

RESULTS

Among 1460 patients born with EA, 97 (7%) were deceased before the age of 1 year, and follow-up data were available for 1287 patients, who constituted our study population. EAs were Ladd classification type III or IV in 89%, preterm birth was observed in 38%, and associated malformations were observed in 52%. Collectively, 61% were readmitted after initial discharge in the first year, 31% for a respiratory cause. Among these, respiratory infections occurred in 64%, and 35% received a respiratory treatment. In logistic regression models, factors associated with readmission for a respiratory cause were recurrence of tracheoesophageal fistula, aortopexy, antireflux surgery, and tube feeding; factors associated with respiratory treatment were male sex and laryngeal cleft.

CONCLUSIONS

Respiratory morbidity in the first year after EA repair is frequent, accounting for >50% of readmissions. Identifying high risk groups of EA patients (ie, those with chronic aspiration, anomalies of the respiratory tract, and need for tube feeding) may guide follow-up strategies.

Adoption in Canada of an international risk scoring tool to predict respiratory syncytial virus hospitalization in moderate-to-late preterm infants

OBJECTIVE

The advisory board to the Ontario Ministry of Health considered adopting the new three-variable international risk scoring tool (IRST) to guide prophylaxis against respiratory syncytial virus hospitalization (RSVH) in moderate-to-late preterm infants born 32-35 weeks' gestational age (wGA). Canada currently uses a nationally validated, seven-variable RST, to predict RSVH in 33-35 wGA infants. We explored the potential implications of switching from the Canadian to the IRST.

METHODS

Predictive accuracy (area under the receiver operating characteristic curve [AUROC]) of the two RSTs and correlations (Spearman rank) and number needed to treat (NNT) between cut-off scores for low-, moderate- and high-risk subjects were assessed.

RESULTS

The RSTs contain many of the same risk factors (birth proximity to the RSV season, smoking, siblings, daycare), with the Canadian RST also including sex, small for GA and familial eczema. Predictive accuracy was similar (AUROC, IRST: 0.773 [sensitivity: 68.9%; specificity: 73.0%] vs Canadian: 0.762 [68.2%; 71.9%]). Significant correlations between cut-off scores (p < .001) and risk categories (p < .001) were apparent, although the correlation coefficients were weak for both (scores: 0.217; categories: 0.055). While the proportion of high-risk infants was similar (IRST: 0.7% vs Canadian: 0.6%), the NNT was lower for the Canadian RST (7.5 vs 14.3), and more infants were assigned moderate risk by the IRST (19.9% vs 9.8%).

CONCLUSIONS

The IRST can be considered simpler (fewer risk factors) than the Canadian RST and its adoption may reduce the number of RSVHs among moderate-to-late preterm infants; however, the cost-effective implications for RSV prophylaxis warrant further investigation.

Occurrence and severity of acute respiratory infections during the first year among very preterm infants: an Epipage-2 cohort analysis

This study aims to describe the incidence of acute respiratory infections (ARI) during the first year in infants born before 32 weeks' gestation, and to analyze and study the risk factors as well as factors associated with oxygen requirement among infants with an ARI, in the palivizumab era. This study included 2571 infants from a nationwide French population-based cohort (Epipage 2). ARI at 1-year corrected age was identified by parental questionnaires. Risk and severity factors included those already known, and detailed information about neonatal morbidities. ARI occurred in 52.2% (n = 1349) of infants. Oxygen therapy was used in 33.2% (n = 391) of infants with an ARI. Risk factors for AII were male sex, bronchopulmonary dysplasia, presence of siblings at home, and childcare in the community together with incomplete treatment palivizumab. Mechanical ventilation in the neonatal period, bronchopulmonary dysplasia, and discharge between October and March were associated with more frequent oxygen requirement. No other factors describing neonatal morbidities were associated with risk of ARI or oxygen requirement.Conclusion: ARIs are still very common during the first year of life of very preterm children, and oxygen therapy is frequently needed. Educational strategies are needed in all families with a very preterm infant. What is Known: • Acute respiratory infections (ARIs) are the first cause of rehospitalizations in preterm children, with bronchopulmonary dysplasia being the main risk factor. • Palivizumab prophylaxis has proven its effect against severe RSV infections, but it is not universal. What is New: • No factor describing neonatal morbidity, except BPD, was associated with ARI occurrence or severity. • BPD and discharge during RSV season were the only factors associated with O₂ requirement during ARI.

Passive Immunoprophylaxis against Respiratory Syncytial Virus in Children: Where Are We Now?

Respiratory syncytial virus (RSV) represents the main cause of acute respiratory tract infections in children worldwide and is the leading cause of hospitalization in infants. RSV infection is a self-limiting condition and does not require antibiotics. However hospitalized infants with clinical bronchiolitis often receive antibiotics for fear of bacteria coinfection, especially when chest radiography is performed due to similar radiographic appearance of infiltrate and atelectasis. This may lead to unnecessary antibiotic prescription, additional cost, and increased risk of development of resistance. Despite the considerable burden of RSV bronchiolitis, to date, only symptomatic treatment is available, and there are no commercially available vaccines. The only licensed passive immunoprophylaxis is palivizumab. The high cost of this monoclonal antibody (mAb) has led to limiting its prescription only for high-risk children: infants with chronic lung disease, congenital heart disease, neuromuscular disorders, immunodeficiencies, and extreme preterm birth. Nevertheless, it has been shown that the majority of hospitalized RSV-infected children do not fully meet the criteria for immune prophylaxis. While waiting for an effective vaccine, passive immune prophylaxis in children is mandatory. There are a growing number of RSV passive immunization candidates under development intended for RSV prevention in all infants. In this review, we describe the state-of-the-art of palivizumab's usage and summarize the clinical and preclinical trials regarding the development of mAbs with a better cost-effectiveness ratio.

Respiratory Failure and Death in Vulnerable Premature Children With Lower Respiratory Tract Illness

Background

Efforts to better understand the risk factors associated with respiratory failure (RF) and fatal lower respiratory tract infection (LRTI) in premature children in developing countries are necessary to elaborate evidenced-based preventive interventions. We aim to characterize the burden of respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) LRTI in premature children and determine risk factors for RF and fatal illness in a vulnerable population.

Methods

This is a prospective, population-based, cross-sectional study. Subjects with severe LRTI were enrolled during respiratory season. Risk factors for RF and death in premature infants were investigated.

Results

A total of 664 premature children participated. Infant’s hospitalization rate due to LRTI was 82.6/1000 (95% confidence interval [CI], 68.6–96.7/1000). Infant’s RSV and hMPV rates were 40.9/1000 (95% CI, 36.3–45.6/1000) and 6.6/1000 (95% CI, 3.9–9.2/1000), respectively. The RF rate was 8.2/1000 (95% CI, 4.9–11.5/1000). The LRTI mortality was 2.2/1000 (95% CI, 0.7–3.7/1000); for RSV, the rate was 0.8/1000 (95% CI, 0–1.7/1000) with a case-fatality ratio of 1.8%. Never breastfeeding, malnutrition, younger than 6 months, congenital heart disease, and lower hematocrit were risk factors for RF. Experiencing pneumonia, pneumothorax, sepsis, or apnea were clinical determinants of poor outcomes.

Conclusions

Premature children under 2 years old in vulnerable environments experience RF and death more often than term counterparts. Modifiable risk factors associated with poor outcomes should prompt evidence-based interventions.

Current State of Respiratory Syncytial Virus Disease and Management

Respiratory syncytial virus (RSV) is a major cause of hospitalizations due to pneumonia and bronchiolitis. Substantial morbidity and socioeconomic burden are associated with RSV infection worldwide. Populations with higher susceptibility to developing severe RSV include premature infants, children with chronic lung disease of prematurity (CLDP) or congenital heart disease (CHD), elderly individuals aged > 65 years, and immunocompromised individuals. In the pediatric population, RSV can lead to long-term sequelae such as wheezing and asthma, which are associated with increased health care costs and reduced quality of life. Treatment for RSV is mainly supportive, and general preventive measures such as good hygiene and isolation are highly recommended. Although vaccine development for RSV has been a global priority, attempts to date have failed to yield a safe and effective product for clinical use. Currently, palivizumab is the only immunoprophylaxis (IP) available to prevent severe RSV in specific high-risk pediatric populations. Well-controlled, randomized clinical trials have established the efficacy of palivizumab in reducing RSV hospitalization (RSVH) in high-risk infants including moderate- to late-preterm infants. However, the American Academy of Pediatrics (AAP), in its 2014 policy, stopped recommending RSV IP use for ≥ 29 weeks' gestational age infants. Revisions to the AAP policy for RSV IP have largely narrowed the proportion of pediatric patients eligible to receive RSV IP and have been associated with an increase in RSVH and morbidity. On the other hand, after reviewing the recent evidence on RSV burden, the National Perinatal Association, in its 2018 clinical practice guidelines, recommended RSV IP use for a wider pediatric population. As the AAP recommendations drive insurance reimbursements for RSV IP, they should be revised to help further mitigate RSV disease burden.

Socioeconomic Impact of RSV Hospitalization

Respiratory syncytial virus (RSV) disease is a significant cause of morbidity and socioeconomic burden worldwide among young children. The majority of RSV-associated lower respiratory tract infections (LRTI) and mortality occurs in developing countries and is associated with various sociodemographic risk factors. Independent risk factors for severe RSV disease include age and premature birth. While RSV mortality in developed countries is lower relative to developing countries, high-risk infants with comorbidities experience higher rates of mortality. RSV LRTI is often severe and is associated with hospitalization, increased need for intensive care unit admission and mechanical ventilation, long-term complications, and caregiver stress and loss of work productivity. Overall, these factors translate to higher health care resource utilization and costs and should be factored into the consideration for RSV prophylaxis. Multiple vaccine candidates and long-acting monoclonal antibodies are in various stages of clinical development. Currently, palivizumab is the only approved RSV immunoprophylaxis available for use in specific high-risk pediatric populations. This review will discuss the socioeconomic impact and health care resource utilization of RSV-related hospitalization (RSVH) as well as various sociodemographic risk factors that can be used to identify children at high risk of developing severe RSV disease.

A Survey of Parental Knowledge of Respiratory Syncytial Virus and Other Respiratory Infections in Preterm Infants

PURPOSE

Evaluate parental knowledge of respiratory syncytial virus (RSV) and other respiratory infections in preterm infants.

DESIGN

Survey.

SAMPLE

Five hundred and eighty-three parents of preterm infants with generalized, Canadian provincial representation.

MAIN OUTCOME

Knowledge of RSV infection, sources of information, and parental understanding of disease risk.

RESULTS

97.9 percent (571/583) of the parents had heard about RSV, since they all had a preterm infant. Sixty-one percent reported having good knowledge of RSV; 19.4 percent had very good knowledge; 19.7 percent had little or no awareness of RSV-related infection. Most (86.3 percent) believed that RSV illness was a very serious condition; 13 percent recognized that it could be a major problem for their child. Principal sources of information were the nurse, doctor and pamphlets. Over 480 participants cited 3 or more sources of additional information-Internet, social media platforms, and educational sessions. Respiratory syncytial virus prophylaxis was a priority, but knowledge regarding the eligibility criteria for prophylaxis is essential.

Burden of respiratory syncytial virus hospitalisation among infants born at 32-35 weeks' gestational age in the Northern Hemisphere: pooled analysis of seven studies

To provide comprehensive information on the epidemiology and burden of respiratory syncytial virus hospitalisation (RSVH) in preterm infants, a pooled analysis was undertaken of seven multicentre, prospective, observational studies from across the Northern Hemisphere (2000–2014). Data from all 32⁰–35⁶ weeks' gestational age (wGA) infants without comorbidity were analysed. RSVH occurred in 534/14 504 (3.7%) infants; equating to a rate of 5.65 per 100 patient-seasons, with the rate in individual wGA groups dependent upon exposure time (P = 0.032). Most RSVHs (60.1%) occurred in December–January. Median age at RSVH was 88 days (interquartile range (IQR): 54–159). Respiratory support was required by 82.0% of infants: oxygen in 70.4% (median 4 (IQR: 2–6) days); non-invasive ventilation in 19.3% (median 3 (IQR: 2–5) days); and mechanical ventilation in 10.2% (median 5 (IQR: 3–7) days). Intensive care unit admission was required by 17.9% of infants (median 6 days (IQR: 2–8) days). Median overall hospital length of stay (LOS) was 5 (IQR: 3–8) days. Hospital resource use was similar across wGA groups except for overall LOS, which was shortest in those born 35 wGA (median 3 vs. 4–6 days for 32–34 wGA; P < 0.001). Strategies to reduce the burden of RSVH in otherwise healthy 32–35 wGA infants are indicated.

Respiratory syncytial virus hospitalizations in US preterm infants after the 2014 change in immunoprophylaxis guidance by the American Academy of Pediatrics

Palivizumab is the only licensed and effective immunoprophylaxis (IP) available to prevent respiratory syncytial virus (RSV) infection in high-risk infants including infants born at ≤35 weeks' gestational age (wGA). In 2014, the American Academy of Pediatrics stopped recommending IP for otherwise healthy 29-34 wGA infants, stating that their risk of RSV hospitalization (RSVH) was similar to term infants. Recent studies have demonstrated a significant decline in IP use after 2014 that was accompanied by an increased risk of RSVH in 29-34 wGA infants vs term infants. Severity and healthcare utilization of RSVH were high among 29-34 wGA infants. In 2018, the National Perinatal Association developed guidelines advocating IP use in all ≤32 wGA infants and 32-35 wGA infants with additional risk factors. Risk factor predictive models can identify infants who are at risk for RSVH and promote cost-effective use of palivizumab until new methods of RSV prevention become available.

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.

Clinical burden of severe respiratory syncytial virus infection during the first 2 years of life in children born between 2000 and 2011 in Scotland

National data from Scotland (all births from 2000 to 2011) were used to estimate the burden associated with respiratory syncytial virus hospitalisation (RSVH) during the first 2 years of life. RSVHs were identified using the International Classification of Diseases 10th Revision codes. Of 623,770 children, 13,362 (2.1%) had ≥ 1 RSVH by 2 years, with the overall rate being 27.2/1000 (16,946 total RSVHs). Median age at first RSVH was 137 days (interquartile range [IQR] 62-264), with 84.3% of admissions occurring by 1 year. Median length of stay was 2 (IQR 1-4) days and intensive care unit (ICU) admission was required by 4.3% (727) for a median 5 (IQR 2-8) days. RSVHs accounted for 6.9% (5089/73,525) of ICU bed days and 6.2% (64,395/1,033,121) of overall bed days (5370/year). RSVHs represented 8.5% (14,243/168,205) of all admissions between October and March and 14.2% (8470/59,535) between December and January. RSVH incidence ranged from 1.7 to 2.5%/year over the study period. Preterms (RSVH incidence 5.2%), and those with congenital heart disease (10.5%), congenital lung disease (11.2%), Down syndrome (14.8%), cerebral palsy (15.5%), cystic fibrosis (12.6%), and neuromuscular disorders (17.0%) were at increased risk of RSVH.Conclusions: RSV causes a substantial burden on Scottish paediatric services during the winter months.What is known:• Respiratory syncytial virus (RSV) is a leading cause of childhood hospitalisation.What is new:• This 12-year study is the first to estimate the burden of RSV hospitalisation (RSVH) in Scotland and included all live births from 2000 to 2011 and followed > 600,000 children until 2 years old.• The overall RSVH rate was 27.2/1000 children, with 2.1% being hospitalised ≥ 1 times.• RSVHs accounted for 6.2% of all inpatient bed days, which rose to 14.2% during the peak months of the RSV season (December-January), equating to over 1400 hospitalisations and nearly 5500 bed days each year.

Impact of the 2014 American Academy of Pediatrics recommendation and of the resulting limited financial coverage by the Italian Medicines Agency for palivizumab prophylaxis on the RSV-associated hospitalizations in preterm infants during the 2016-2017 epidemic season: a systematic review of seven Italian reports

BACKGROUND

The only pharmacologic prophylaxis against respiratory syncytial virus (RSV) infection in preterm infants is the humanized monoclonal antibody palivizumab. After the 2014 modification of the American Academy of Pediatrics (AAP) recommendations, the Italian Medicines Agency (AIFA) limited the financial coverage for palivizumab prescriptions to otherwise healthy preterm infants with < 29 weeks of gestational age (wGA) aged < 12 months at the beginning of the 2016-2017 RSV season. However, due to the effect on disease severity and hospitalizations following this limitation, shown by several Italian clinical studies, in November 2017 AIFA reinstated the financial coverage for these infants. In this systematic review, we critically summarize the data that show the importance of palivizumab prophylaxis.

METHODS

Data from six Italian pediatric institutes and the Italian Network of Pediatric Intensive Care Units (TIPNet) were retrieved from the literature and considered. The epidemiologic information for infants 29-36 wGA, aged < 12 months and admitted for viral-induced acute lower respiratory tract infection were retrospectively reviewed. RSV-associated hospitalizations were compared between the season with running limitation, i.e. 2016-2017, versus 2 seasons before (2014-2015 and 2015-2016) and one season after (2017-2018) the AIFA limitation.

RESULTS

During the 2016-2017 RSV epidemic season, when the AIFA limited the financial coverage of palivizumab prophylaxis based on the 2014 AAP recommendation, the study reports on a higher incidences of RSV bronchiolitis and greater respiratory function impairment. During this season, we also found an increase in hospitalizations and admissions to the Pediatric Intensive Care Units and longer hospital stays, incurring higher healthcare costs. During the 2016-2017 epidemic season, an overall increase in the number of RSV bronchiolitis cases was also observed in infants born full term, suggesting that the decreased prophylaxis in preterm infants may have caused a wider infection diffusion in groups of infants not considered to be at risk.

CONCLUSIONS

The Italian results support the use of palivizumab prophylaxis for otherwise healthy preterm (29-36 wGA) infants aged < 6 months at the beginning of the RSV season.

Pediatric Pulmonology year in review 2018: Asthma, physiology/pulmonary function testing, and respiratory infections

Pediatric Pulmonology publishes original research, reviews, and case reports related to a wide range of children's respiratory disorders. In our "Year in Review" series, we summarize publications in our major topic areas from 2018, in the context of selected literature in these areas from other journals relevant to our discipline. This review covers selected articles on asthma, physiology/lung function testing, and respiratory infections.

Practical Guidance for Clinical Microbiology Laboratories: Viruses Causing Acute Respiratory Tract Infections

Respiratory viral infections are associated with a wide range of acute syndromes and infectious disease processes in children and adults worldwide. Many viruses are implicated in these infections, and these viruses are spread largely via respiratory means between humans but also occasionally from animals to humans. This article is an American Society for Microbiology (ASM)-sponsored Practical Guidance for Clinical Microbiology (PGCM) document identifying best practices for diagnosis and characterization of viruses that cause acute respiratory infections and replaces the most recent prior version of the ASM-sponsored Cumitech 21 document, Laboratory Diagnosis of Viral Respiratory Disease, published in 1986. The scope of the original document was quite broad, with an emphasis on clinical diagnosis of a wide variety of infectious agents and laboratory focus on antigen detection and viral culture. The new PGCM document is designed to be used by laboratorians in a wide variety of diagnostic and public health microbiology/virology laboratory settings worldwide. The article provides guidance to a rapidly changing field of diagnostics and outlines the epidemiology and clinical impact of acute respiratory viral infections, including preferred methods of specimen collection and current methods for diagnosis and characterization of viral pathogens causing acute respiratory tract infections. Compared to the case in 1986, molecular techniques are now the preferred diagnostic approaches for the detection of acute respiratory viruses, and they allow for automation, high-throughput workflows, and near-patient testing. These changes require quality assurance programs to prevent laboratory contamination as well as strong preanalytical screening approaches to utilize laboratory resources appropriately. Appropriate guidance from laboratorians to stakeholders will allow for appropriate specimen collection, as well as correct test ordering that will quickly identify highly transmissible emerging pathogens.

Risk scoring tool to predict respiratory syncytial virus hospitalisation in premature infants

BACKGROUND

The objective was to develop a risk scoring tool which predicts respiratory syncytial virus hospitalisation (RSVH) in moderate-late preterm infants (32-35 weeks' gestational age) in the Northern Hemisphere.

METHODS

Risk factors for RSVH were pooled from six observational studies of infants born 32 weeks and 0 days to 35 weeks and 6 days without comorbidity from 2000 to 2014. Of 13 475 infants, 484 had RSVH in the first year of life. Logistic regression was used to identify the most predictive risk factors, based on area under the receiver operating characteristic curve (AUROC). The model was validated internally by 100-fold bootstrapping and externally with data from a seventh observational study. The model coefficients were converted into rounded multipliers, stratified into risk groups, and number needed to treat (NNT) calculated.

RESULTS

The risk factors identified in the model included (i) proximity of birth to the RSV season; (ii) second-hand smoke exposure; and (iii) siblings and/or daycare. The AUROC was 0.773 (sensitivity: 68.9%; specificity: 73.0%). The mean AUROC from internal bootstrapping was 0.773. For external validation with data from Ireland, the AUROC was 0.707 using Irish coefficients and 0.681 using source model coefficients. Cut-off scores for RSVH were ≤19 for low- (1.0%), 20-45 for moderate- (3.3%), and 50-56 (9.5%) for high-risk infants. The high-risk group captured 62.0% of RSVHs within 23.6% of the total population (NNT 15.3).

CONCLUSIONS

This risk scoring tool has good predictive accuracy and can improve targeting for RSVH prevention in moderate-late preterm infants.